Light Energy Conversion Efficiency Research Articles

Membraneless organelles assembled by AuNPs-enzyme integration in non-photosynthetic bacteria: Achieving high specificity and selectivity for solar hydrogen production

The emergence of semiartificial photosynthesis holds great promise for improving light energy capture and conversion efficiency. However, achieving high product specificity and selectivity in semiartificial photosynthetic systems remains a challenge. In this study, we employed genetic engineering techniques to construct a membraneless organelle in E. coli, serving as the photoreaction carrier. The self-assembly of photosensitizers and hydrogenase within the carrier has successfully established a semiartificial photosynthetic model characterized by high product specificity and selectivity. In this model system, electrons were directly transferred to hydrogenase upon AuNPs light excitation in membraneless organelle, eliminating the need for additional electron mediators and bypassing the use of intracellular NADH/NAD+ as a reducing agent to avoid byproduct formation. The semiartificial photosynthetic system demonstrated an 11782-fold and 40-fold increase in hydrogen production compared to bare AuNPs and the empty vector E. coli hybrid system, respectively. This membraneless organelle holds the potential to robustly support the specific synthesis of high-energy-density, value-added compounds through solar energy conversion.

Transcriptomics combined with physiology reveals the effect of different light qualities on the development of Fritillaria cirrhosa in the Qinghai Tibet Plateau

Fritillaria cirrhosa, a high-altitude plant susceptible to environmental conditions, commonly grows beneath bushes and is categorized as shade-tolerant. The development and secondary metabolite synthesis of F. cirrhosa are significantly influenced by light quality. This study investigated the physiological responses and molecular mechanisms of F. cirrhosa to different light qualities using colored agricultural film treatments. The results demonstrated that the number of sprout tumbles in F. cirrhosa was significantly reduced by the different colored film treatments. The quality of the fruits exhibited a notable improvement under the blue film (BF) treatment compared to the other groups (P < 0.05). The guanosine content showed a substantial increase of 440.55% under the BF treatment relative to the white film (WF), and the uracil content significantly increased by 171.27% in BF and by 296.38% in the green film (GF). Leaf thickness was considerably higher under the GF treatment than under the other conditions. F. cirrhosa demonstrated enhanced photosynthesis when exposed to BF and GF (P < 0.05). The transcriptome results indicated 75 differentially expressed genes (DEGs) involved in photosynthesis-related pathways that regulated photosynthetic utilization efficiency by encoding photosynthetic antenna proteins (Lhca and Lhcb), photosynthetic electron transporters (PsbE, PsbP, and PetA), and carbon fixation enzymes (PPC, PPDK, and rbcL). Most these genes were upregulated in BF and GF, improving the light energy conversion efficiency, photosynthetic electron transport rate, and CO2 assimilation ability in F. cirrhosa. Notably, 44 DEGs involved in flavonoid metabolic pathways (PAL, HCT, 4CL, CHS, CHI, and ANS) showed higher expression levels in WF and yellow film (YF), differing in the regulation of the photosynthetic pathway. This suggested that F. cirrhosa can utilize nutrients produced by photosynthesis more efficiently under BF and GF, and does not require excessive amounts of flavonoids for maintaining cell homeostasis. These results offer valuable insights into the transcriptional changes and molecular processes occurring in F. cirrhosa in response to different light qualities and provide a basis for research on the mechanisms of photo regulation, cultivation, and ecological adaptation in F. cirrhosa.

Photon Management Enabled by Opal and Inverse Opal Photonic Crystals: from Photocatalysis to Photoluminescence Regulation.

Light is a promising renewable energy source and can be converted into heat, electricity, and chemical energy. However, the efficiency of light-energy conversion is largely hindered by limited light-absorption coefficients and the low quantum yield of current-generation materials. Photonic crystals (PCs) can adjust the propagation and distribution of photons because of their unique periodic structures, which offers a compelling platform for photon management. The periodicity of materials with an alternating refractive index can be used to manipulate the dispersion of photons to generate the photonic bandgap (PBG), in which light is reflected. The slow photon effect, i. e., photon propagation at a reduced group velocity near the edges of the PBG, is widely regarded as another valuable optical property for manipulating light. Furthermore, multiple light scattering can increase the optical path, which is a vital optical property for PCs. Recently, the light reflected by PBG, the slow photon effect, and multiple light scattering have been exploited to improve light utilization efficiency in photoelectrochemistry, materials chemistry, and biomedicine to enhance light-energy conversion efficiency. In this review, the fabrication of opal or inverse opal PCs and the theory for improving the light utilization efficiency of photocatalysis, solar cells, and photoluminescence regulation are discussed. We envision photon management of opal or inverse opal PCs may provide a promising avenue for light-assisted applications to improve light-energy-conversion efficiency.

Effects of light and water availability on the growth of Aglaia duperreana seedlings.

Aglaia duperreana, a species with a long cultivation history, is of high ornamental value. To understand the growth and photosynthetic changes of A. duperreana seedlings under variable environmental conditions, we conducted an experiment with light intensities adjusted at 70%, 50% and 30%, crossed with three moisture treatments at 70%, 50% and 30% of field capacity, and a control group which maintained 90% light intensity and 90% field capacity. The results showed that both drought stress and shading propensity significantly inhibited the growth of A. duperreana seedlings, with stronger impacts from drought stress. The increments in stem height and ground diameter, net photosynthetic rate, transpiration rate, stomatal conductance, and chlorophyll content were decreased with the maximum declines by 71.4%, 81.2%, 93.2%, 71.5%, 70.6% and 30.4%, respectively. Under severe drought stress (30% of field capacity), partial shading (50% of translucency) appeared to lessen the detrimental effects of drought. The combination of 70% translucency and 70% field capacity was optimal, resulting in higher increments in stem height, leaf area, net photosynthetic rate, transpiration rate, and stomatal conductance. The maximum fluorescence, variable fluorescence, PSⅡ potential activity, and PSⅡ maximum light energy conversion efficiency increased and then decreased with decreasing moisture. These findings suggested that A. duperreana could adapt to drought and shading stress by modulating growth, enhancing chlorophyll content, and adjusting photosynthetic system. Maintaining translucency at 70% and field moisture capacity at 70% could promote photosynthesis, with positive consequences on growth of A. duperreana.

Properties and photosynthetic promotion mechanisms of artificial humic acid are feedstock-dependent

AbstractThe artificial humic acids (AHA) approach contributes to achieving the carbon (C) emission peaking and neutrality goal through efficient recycling of waste biomasses and promotion of plant photosynthesis. However, the dependence of their production processes and photosynthetic promotion mechanisms on feedstocks remains unclear. In this study, waste biomasses including camphor leaves (CL), corn stalks (CS), peanut shells (PS), and mixed cyanobacteria (MC) have been respectively converted into artificial humic acids through an environmentally friendly hydrothermal humification approach. The dynamic humification process of different feedstocks and the composition, structural properties, and electron transfer capacity of AHA products were determined. Moreover, the different AHA products were applied to corn to explore their respective photosynthetic promotion mechanisms. High relative contents of lignin and C/N in feedstocks are not conducive to the formation of photodegradable substances and the redox property in AHA. The application of AHA increased the net photosynthetic rate and biomass C of corn by 70–118% and 22–39%, respectively. The AHA produced from higher H/C (0.19) and hemicellulose content (17.09%) in feedstocks (e.g., MC) increased corn photosynthesis by improving light energy capture and conversion efficiency in the PSII process. In contrast, the AHA produced from a higher content of lignin (19.81%) and C/N (7.67) in feedstocks (e.g., CS) increased corn photosynthesis by providing functional enzymes (proteins) and nutrients for leaves. This work provides new insights into the utilization of renewable resources, and the artificial humic acids approach sheds light on environmental sustainability by constructing a closed loop of C in environments. Graphical Abstract

Intraspecific plasticity and co-variation of leaf traits facilitate Ficus tinctoria to acclimate hemiepiphytic and terrestrial habitats.

Despite intensive studies on plant functional traits, the intraspecific variation and their co-variation at the multi-scale remains poorly studied, which holds the potential to unveil plant responses to changing environmental conditions. In this study, intraspecific variations of 16 leaf functional traits of a common fig species, Ficus tinctoria G. Frost., were investigated in relation to different scales: habitat types (hemiepiphytic and terrestrial), growth stages (small, medium and large) and tree crown positions (upper, middle and lower) in Xishuangbanna, Southwest China. Remarkable intraspecific variation was observed in leaf functional traits, which was mainly influenced by tree crown position, growth stage and their interaction. Stable nitrogen isotope (δ15N) and leaf area (LA) showed large variations, while stable carbon isotope (δ13C), stomata width and leaf water content showed relatively small variations, suggesting that light- and nitrogen-use strategies of F. tinctoria were plastic, while the water-use strategies have relatively low plasticity. The crown layers are formed with the growth of figs, and leaves in the lower crown increase their chlorophyll concentration and LA to improve the light energy conversion efficiency and the ability to capture weak light. Meanwhile, leaves in the upper crown increase the water-use efficiency to maintain their carbon assimilation. Moreover, hemiepiphytic medium (transitional stage) and large (free-standing stage) figs exhibited more significant trait differentiation (chlorophyll concentration, δ13C, stomata density, etc.) within the crown positions, and stronger trait co-variation compared with their terrestrial counterparts. This pattern demonstrates their acclimation to the changing microhabitats formed by their hemiepiphytic life history. Our study emphasizes the importance of multi-scaled intraspecific variation and co-variation in trait-based strategies of hemiepiphyte and terrestrial F. tinctoria, which facilitate them to cope with different environmental conditions.

Effects of Sodium Selenite on the Growth and Photosystem II Activity of Arthrospira platensis Gom.

Arthrospira platensis (A. platensis) is a species of cyanobacteria with high economic value; the species is commercially well known as Spirulina platensis, and A. platensis was used in this paper. Its high adaptability, high photosynthetic efficiency, and fast growth rate make it one of the few cyanobacteria that can be cultivated on a large scale. Therefore, using the selenium enrichment property of A. platensis to cultivate selenium-enriched A. platensis will not only enhance the physiological efficacy of A. platensis but also increase its economic value significantly. In this study, we investigated the effects of sodium selenite on the growth and photosynthetic performance of A. platensis selenium by setting different amounts and methods of sodium selenite addition, and we explored the optimal culture conditions of the best dosage and method of sodium selenite addition. The results showed that the experimental group treated with sodium selenite at 700 μmol/L had the fastest growth, and the contents of soluble protein, phycocyanin C, and chlorophyll a increased by approximately 67.9%, 1.44 times, and 38.8% compared to the control group, respectively. Superoxide dismutase (SOD) and catalase (CAT) activity increased by 1.88-fold and 65%, respectively, and malondialdehyde (MDA) levels were reduced by 62% compared to the control group. The results of the OJIP assay showed that the J and I points were significantly higher at the batch addition and treatment concentration of 700 μmol/L, with the rate of QA being reduced and the proportion of the slowly reduced PQ pool being increased. The values of the maximum light energy conversion efficiency (Fv/Fm) per unit of reaction center were higher in both sodium selenite treatment groups than in the control group, indicating that the light energy conversion efficiency of A. platensis was promoted under all concentration treatment conditions. The batch addition of sodium selenite at concentrations less than 700 μmol/L resulted in significantly higher ABS/RC values than the control, and they were far superior to the one-time addition method. The reason for this may have been that the batch addition of sodium selenite at low concentrations increased the light absorption capacity of the unit reaction center of PSII, resulting in a rise in captured light energy, a rise in the energy captured by the reaction center for electron transfer (ETo/RC), a decrease in the energy dissipated in the absorption of light energy by the reaction center (DIo/RC), and an increase in the photosynthetic performance index (PI abs).

Constructing MoO3-x/Mn0.3Cd0.7S S-scheme heterojunction with LSPR and photothermal effects for enhanced full spectrum hydrogen evolution

Some nonstoichiometric semiconductors exhibit excellent near-infrared (NIR) absorption due to their unique localized surface plasmon resonance (LSPR) effect, which is conducive to improving efficiency of light energy conversion to make them promising candidates for efficient photocatalytic hydrogen (H2) evolution. Herein, we constructed a novel 1D/1D MoO3-x/Mn0.3Cd0.7S (MO/MCS) S-scheme heterojunction with LSPR and photothermal double effects for boosted full solar spectrum-driven H2 evolution. The light absorption of MO/MCS was expanded to NIR region through the LSPR effect of MO. Meanwhile, the impressive photothermal effect of MO can increase the surface temperature of the photocatalyst particles under light irradiation, which can further accelerate the photoreaction. According to the experimental and theoretical calculation results, the formation of S-scheme heterojunction was confirmed, which boosted the separation of photo-induced carriers. Consequently, the H2 evolution performance of judiciously designed MO/MCS composites was significantly enhanced with an optimal H2 evolution of 2.235 mmol·g−1·h−1, 30.6 times that of pure MCS. This work provides a valuable insight into the development of highly efficient full solar spectrum-driven photocatalysts through utilizing the synergetic effects of LSPR effect, photothermal effect, and S-scheme heterojunction.

Morpho-Physiological, Chlorophyll Fluorescence, and Diffuse Reflectance Spectra Characteristics of Lettuce under the Main Macronutrient Deficiency

The aim of the present work was to assess the physiological state of plants and photosynthetic apparatus activity in lettuce (Lactuca sativa L.) by non-invasive methods (leaf diffuse reflectance spectroscopy and chlorophyll fluorescence) under the deficiency of one of the macronutrients (nitrogen, phosphorus, or potassium). Our experiments assessed the deficiency of each of the macronutrients relative to plants vegetating under optimal nutrition. The used methods showed that the deficiency of macronutrients causes changes in the optical characteristics of lettuce plants (cvs. ‘Vitaminnyi’ and ‘Kokarda’), including a decrease in the chlorophyll content (57% and 51%) and a change in metabolism, which leads to a decrease in the efficiency of light energy conversion in photochemical processes of photosynthesis and an increase in the dissipation of excess light energy (19% and 10%). Linear regression equations, describing the relationship between net productivity and spectral characteristics of diffuse leaf reflectance with high accuracy, have been obtained. Changes in all studied indicators of the physiological state of plants under the influence of macronutrient deficiency are more pronounced at the early stages of development than in later periods, when the first symptoms of aging appear (decrease in ChlRI). The observed differences between lettuce cultivars and their response to nitrogen, phosphorus, or potassium deficiency are non-specific and mainly represent quantitative variation. The method for assessing the spectral characteristics of diffuse reflection of leaves seems to be the most promising for monitoring the physiological status of plants and early detection of nitrogen, phosphorus, or potassium deficiency.

Self-templated fabrication of porous Bi5O7I nanosheets for enhanced visible light CO2 photoreduction

Photocatalytic CO2 reduction is limited by high reaction barriers of CO2 activation, resulting in low conversion efficiency of light energy to chemical energy, especially within the visible light range. To enhance the performance of photocatalytic CO2 reduction, the rational design of the chemical environment on the catalyst surface is conducive to the activation of reactive molecules. Here, we prepared porous Bi5O7I with surface charge-rich Bi(3−x)+ ions by template calcination. The experimental results show that Bi ions accumulated charges on the surface of Bi5O7I have superior adsorption and activation abilities for CO2 molecules than the precursor BiOIO3. Besides, Bi5O7I exhibits better charge transfer capability and roughly double the catalytic activity under visible light irradiation for CO production. This work developed a new facile approach for fabrication of high-performance photocatalysts and provided new insight on the mechanism of CO2 photoreduction.

Effects of Elevated Surface Ozone Concentration on Photosynthetic Fluorescence Characteristics and Yield of Soybean Parents and Offspring

Global climate change presents a significant threat to food security. Analyzing the effects of elevated ozone (O3) concentration on photosynthetic fluorescence characteristics and yield addresses the damage of climate change on crops, which would serve food security. With open-top chambers (OTCs) and Tiefeng-29 soybeans, we investigated the responses of chlorophyll concentration, fluorescence characteristics, net photosynthetic rate (Pn) and yield components to different O3 concentrations, which included CK (ambient concentration approximately 45 nL·L−1, T1 (80 ± 10) nL·L−1 and T2 (120 ± 10) nL·L−1 O3. The parent soybeans (S1) were planted in the current year, and O3 fumigation commenced 20 days after seedling emergence. Aeration was stopped at maturity, and the offspring soybeans (S2) were retained after harvest for further experiments. In the following year, S1 and S2 soybeans were planted, and O3 fumigation began 20 days after seedling emergence. The results show that leaf chlorophyll a (chla) and chlorophyll b (chlb) significantly decreased with longer O3 fumigation time both in parents and offspring, causing damage to the light-trapping ability while the offspring suffered an earlier decrease. The elevated O3 damaged the electron transfer process by significantly reducing the original and actual photochemical efficiencies of PSII both in parents and offspring. The electron transfer rate (ETR) of the parents and offspring decreased, while the difference between them was not significant after O3 treatment. The non-photochemical quenching coefficient (NPQ) showed an increasing trend along time but showed no significant difference between parents and offspring. An elevated concentration of O3 significantly reduced Pn, while the differences in Pn between the parents and the offspring were not significant. Elevated O3 resulted in reduced yields in both parent and offspring soybeans. Although it was found that the offspring soybeans exhibited higher yields than the parents, their reduction in yield was more significant. Therefore, elevated O3 concentration reduced soybean yield through damaging photosynthetic process and electron transfer capacity by impairing energy conversion and material accumulation capacity. The offspring had relatively higher light energy conversion efficiency than the parents, resulting in a higher yield than the parents under all treatments.

Investigations of Charge Transfer Processes on Plasmonic Cathode Electrodes

The establishment of efficient light energy conversion system is an important issue in the field of photoelectrochemical region. For the realization of it, the wide-band semiconductor electrode could be the good candidate. However, semiconductor electrodes often have the limitation to the ultraviolet region because of their band gap energy. Because the sunlight energy mainly consists of visible light, the visible-light induced photoenergy conversion is a challenging issue. As the breakthrough for it, recently, the combination of the plasmonic metal nanostructures with wide semiconductor electrodes has been received much attention because of the addition of visible light response characters. Up to now, the various systems of the anodic reaction controls have been established. Recently, the cathode system which can control the reduction reactions at metal semiconductor interfaces have been reported via the introduction of plasmonic metal nanostructures into the p-type semiconductor electrodes. In our previous study, we have established the plasmonic photocathode by using the Ag nanostructures with the p-type GaP electrode [1]. In this system, it can be considered as the holes excited in the metal structures injected into the valence band of the p-type semiconductor and the remained electron are consumed in the hydrogen evolution reaction. In addition, we have observed the unique pH dependence on the hydrogen evolution which could not be observed on conventional metal electrodes. For understanding the unique reaction selectivity on the plasmonic cathode electrode, the detail understanding about both the charge transfer process and absolute electrochemical potential of generated electrons. In this study, we have attempted to obtain such information through the various chemical reactions using the various types of plasmonic structures. Through the various photoelectrochemical measurements, we have confirmed the changes in the electrochemical potential of excited electrons depending on the optical characters of plasmonic structures. The unique molecular selectivity was also observed. Our current research would provide the novel insight for the accurate design of the high efficient visible light conversion device.[1] H. Minamimoto et al., Chem. Lett., 2020, 49, 806.

Photoluminescence Property of Cu(In,Ga)S2 Quantum Dots Depending on Their Composition and Nanostructure

Multinary quantum dots (QDs) composed of less toxic elements, such as CuInS2 and AgInS2, have been intensively investigated for the application to highly efficient solar energy conversion systems and novel luminescent devices, because their electronic energy structure and optical properties can be controlled by the size and chemical composition of QDs. Recently we have successfully prepared alloy QDs composed of Ag–In–Ga–S and Ag–In–Ga–Se semiconductors, the Eg of which was tunable in the visible and near-IR wavelength regions, respectively [1, 2]. These QDs exhibited a narrow PL peak assignable to the band-edge emission and their peak wavelengths were widely tunable by changing their Eg. However, there have been few investigations to prepare Cu-based multinary QDs with a narrow PL peak. Thus, in this study, we prepare spherical QDs composed of less-toxic Cu–In–Ga–S (CIGS) alloy semiconductor and investigate their composition-dependent optical properties.The synthesis of CIGS QDs was carried out by our previous heating-up method with a slight modification [1]. Powders of Cu(OAc)2, In(acac)3, Ga(acac)3, elemental sulfur were dispersed in a mixture solution of oleylamine and dodecanethiol, followed by the heat treatment at 300 oC. The resulting solution was subjected to centrifugation to remove large precipitates, and QDs were isolated from the supernatant by adding methanol as a non-solvent. Thus-obtained QDs were used as a core to prepare cores-shell-structured particles, in which the surface of CIGS core was coated by thin shell composed of ZnS or GaSx.The chemical composition of obtained QDs was controlled by the fractions of individual metal salts used as precursors. The Cu/(In+Ga) and In/(In+Ga) of obtained QDs roughly agreed with those used in preparation. The obtained QDs were spherical and their average diameter decreased from 5.4 nm to 3.4 nm with an increase in the In fraction. The absorption spectra of CIGS QDs were varied depending on both the fractions of Cu and In. The onset wavelength of QDs was blue-shifted from 840 nm to 540 nm with a decrease in the Cu/(In+Ga) in preparation from 0.7 to 0.1 when the QDs were prepared with the fixed ratio of In/(In+Ga)= 0.7. On the other hand, the QDs exhibited a blue shift of absorption onset from ca. 750 nm to 480 nm with a decrease in In/(In+Ga) ratio from 1.0 to 0 under the fixed Cu fraction in preparation, Cu/(In+Ga)= 0.3. The obtained Eg monotonously decreased from 2.77 eV to 1.74 eV with an increase in In/(In+Ga) ratio from 0 to 1.0, and these values were larger than those of corresponding bulk semiconductors due to the quantum size effect. From the ionization energy of the QDs evaluated from the onset energy of the photoelectron yield spectra in air, we determined the electronic energy structure of CIGS QDs. With a decrease in the Eg of QDs, the conduction band minimum level shifted to a lower level from ca. –2.3 eV to –3.4 eV, while the valence band maximum level was almost constant to ca. 5.1–5.2 eV.Surface coating of CIGS QDs with other semiconductor shells increased the photoluminescence (PL) intensity. The ZnS shell coating to form CIGS@ZnS core-shell QDs produced a PL peak at 649 nm (FWHM: 0.47 eV), being much broader than that of CIGS cores (FWHM: 0.23 eV) because of alloying at the interface between ZnS shell and CIGS core, though the PL quantum yield (QY) increased to 30% from 8%. In contrast, the GaSx coating on CIGS QD surface enlarged the intensity of PL peak without changing its peak width: CIGS@GaSx QDs exhibited a narrow PL peak (FWHM: 0.20 eV) at 671 nm, being comparable to the PL peak of CIGS QDs (the peak wavelength of 675 nm and the FWHM of 0.23 eV). The PL QY was also increased to 27% from 8% by the GaSx coating on CIGS QDs. The tunabilities of electronic energy structure and PL property of CIGS QDs are useful for constructing efficient light energy conversion systems and luminescent devices.[1] T. Kameyama, et al., ACS Applied. Mater. Interfaces 2018, 10, 42844-42855.[2] T. Kameyama, et al., ACS Appl. Nano Mater. 2020, 3, 3275-3287.

S-scheme Co3(PO4)2/Twinned-Cd0.5Zn0.5S homo-heterojunction for enhanced photocatalytic H2 evolution

Heterojunction photocatalysts have been demonstrated to be effective for the interfacial charge transfer and utilization, if the charge transfer in bulk phase can be promoted, more photoinduced charges can be utilized to achieve a higher efficiency of light energy conversion. Herein, twinned-Cd0.5Zn0.5S (T-CZS) homojunction formed by zinc blende Cd0.5Zn0.5S (ZB-CZS) and wurtzite Cd0.5Zn0.5S (WZ-CZS) is obtained via a facile hydrothermal method, and then Co3(PO4)2 is introduced to the surface of T-CZS to form homo-heterojunction using a solvent evaporation strategy. The photocatalytic H2 evolution tests show that the activity of T-CZS is obviously higher than ZB-CZS or WZ-CZS, and Co3(PO4)2 can increase the H2 releasing rate of T-CZS from 13.0 mmol·h−1·g−1 to 64.8 mmol·h−1·g−1 over 5.7 wt% Co3(PO4)2/T-CZS. The apparent quantum efficiency (AQE) can reach 6.4% under 400 nm light irradiation. Under 800 nm near-infrared light (NIR), the H2 releasing rate can reach 0.23 mmol·h−1·g−1. The investigation shows that the carrier transfer between T-CZS and Co3(PO4)2 follows the S-scheme transfer path according to the electron paramagnetic resonance spectroscopy analysis and calculation by density flooding theory (DFT) The enhanced activity of Co3(PO4)2/T-CZS can be mainly attributed to the homo-heterojunction synergistic effect between ZB-CZS/WZ-CZS homojunction in T-CZS and the S-scheme heterojunction between T-CZS and Co3(PO4)2, which well avoids the rapid recombination of bulk and surface electron-hole pairs by accelerating charge transfer. Meanwhile, the improved light-harvesting ability, more active sites and lower H2 production overpotential induced by Co3(PO4)2, jointly contribute to a quick kinetics of H2 evolution. In addition, other metal phosphates MPO4 (M = Ba, Bi, Ag and Zn) are also employed to enhance the activity of T-CZS, they are all effective candidates for construction homo-heterojunction with T-CZS.

ISSR molecular markers and anatomical structures can assist in rapid and directional screening of cold-tolerant seedling mutants of medicinal and ornamental plant in Plumbago indica L.

Plumbago indica L. is a perennial herb with ornamental and anticancer medicinal functions widely distributed in the tropics. It is affected by temperature and cannot bloom normally in colder subtropical regions, which seriously affects its ornamental value. To create low-temperature resistance mutants and enrich new germplasm resources, this study used tissue culture and chemical reagent (0.5 mmol/L NaN3) and low-temperature stress (0°C, full darkness for 48h) induction to target and screen for cold-resistance mutants. The results showed that the ISSR band polymorphism ratio of the 24 suspected mutant materials was 87.5%. The DNA profiles of the 9 mutants initially identified were altered. The content of plumbagin in the stems and leaves of the mutants was examined, and it was found that the accumulation in the leaves of the mutant SA24 could be as high as 3.84 times that of the control, which was 0.5991%. There were significant differences in the anatomical structures of roots, stems and leaves. The mutants mostly exhibited reduced root diameter (only 0.17-0.69 times that of CK), increased stem diameter (up to 2.19 times that of CK), enlarged mesophyll cells, increased thickness (up to 1.83 times that of CK) and high specificity, which are thought to be important for the different cold resistance obtained by the mutants. In the cold resistance experiment, four cold-tolerant mutants were successfully screened according to their morphological characteristics and physiological indexes, and the mutagenesis efficiency could be as high as 2.22% and did not affect the accumulation of plumbagin in their stems and leaves, even higher than CK. The responses of the screened mutants SA15, SA19, SA23 and SA24 to low temperature showed slower leaf wilting, higher light energy conversion efficiency, less accumulation of MDA content, increased enzymatic activities of antioxidant enzymes (SOD, CAT, POD) and more accumulation of soluble sugars and proline content. These characteristics are consistent with the response of cold-resistance plants to low temperatures. The cold- resistance mutants cultivated in soil were observed of agronomic and ornamental traits for one year, mainly manifested as delayed flowering and delayed entry into the senescence stage. This study provides a more rapid and accurate technique for identifying and screening cold-tolerant mutants, and lays the foundation for future experiments on the creation of new cold-resistant varieties.

Research progress in physiological effects of resistant substances of Urtica dioica L. on animal performance and feed conversion.

Several members of family Urticaceae are mainly found in the temperate and subtropical zones of the Northern Hemisphere and are important medicinal plants. Among them, Urtica dioica L. (Urticaceae) is an annual or perennial herb that has been used for feeding and medicinal purposes since long time and is the most exploited species of Urticaceae. Recently, it has received attention to be used as animal feed, as its fresh leaves fed to animals in moderate, dried, and other forms. This review details the advantages of U. dioica as an alternative feed in terms of germplasm specificity, nutritional composition, and feed application status. Its roots, stems, leaves, and seeds are rich in active ingredients. It has also been found to have anticancer effects through antioxidant action and promotion of apoptosis of cancer cells. In shady conditions, U. dioica is highly adaptable while under stressful conditions of drought; it also reduces light absorption and ensures carbon assimilation through light energy conversion efficiency. Therefore, it can be added to animal diets as a suitable feed to reduce costs and improve economic efficiency. This paper investigates the feasibility of using U. dioica as a feed and systematically presents the progress of research and exploitation of U. dioica.

Numerical optimization and performance evaluation of ZnPC:PC70BM based dye-sensitized solar cell

The increase in global energy consumption and the related ecological problems have generated a constant demand for alternative energy sources superior to traditional ones. This is why unlimited photon-energy harnessing is important. A notable focus to address this concern is on advancing and producing cost-effective low-loss solar cells. For efficient light energy capture and conversion, we fabricated a ZnPC:PC70BM-based dye-sensitized solar cell (DSSC) and estimated its performance using a solar cell capacitance simulator (SCAPS-1D). We evaluated the output parameters of the ZnPC:PC70BM-based DSSC with different photoactive layer thicknesses, series and shunt resistances, and back-metal work function. Our analyses show that moderate thickness, minimum series resistance, high shunt resistance, and high metal-work function are favorable for better device performance due to low recombination losses, electrical losses, and better transport of charge carriers. In addition, in-depth research for clarifying the impact of factors, such as thickness variation, defect density, and doping density of charge transport layers, has been conducted. The best efficiency value found was 10.30% after tweaking the parameters. It also provides a realistic strategy for efficiently utilizing DSSC cells by altering features that are highly dependent on DSSC performance and output.

Effect of different size microplastic particles on the construction of algal-bacterial biofilms and microbial communities

Algal-bacterial symbiotic system is a biological purification system that combines sewage treatment with resource utilization and has the dual effects of carbon sequestration and pollution reduction. In this study, an immobilized algal-bacterial biofilm system was constructed for the treatment of natural sewage. Effects of exposure to microplastics (MPs) with different particle diameters (0.065 μm, 0.5 μm and 5 μm) were determined in terms of algal biomass recovery efficiency, the composition of extracellular polymeric substances (EPS) and morphologic characteristics. The impacts of MPs on the bacterial diversity and community structure of biofilms were also examined. The metagenomic analysis of key microorganisms and related metabolism pathways involved in system was further investigated. Results showed that following exposure to 5 μm MP, a maximum algal recovery efficiency of 80% was achieved, with a minimum PSII primary light energy conversion efficiency (Fv/Fm ratio) of 0.513. Furthermore, 5 μm MP caused the highest level of damage to the algal-bacterial biofilm, enhancing the secretion of protein-rich EPS. The biofilm morphology became rough and loose following exposure to 0.5 μm and 5 μm MP. Community diversity and richness were significantly high in biofilms exposed to 5 μm MP. Proteobacteria (15.3–24.1%), Firmicutes (5.0–7.8%) and Actinobacteria (4.2–4.9%) were dominant in all groups, with exposure to 5 μm MP resulting in the highest relative abundance for these species. The addition of MPs promoted the related metabolic functions while inhibited the degradation of harmful substances by algal-bacterial biofilms. The findings have environmental significance for the practical application of algal-bacterial biofilms for sewage treatment, providing novel insights into the potential effects of MPs on immobilized algal-bacterial biofilm systems.

Effects of Graphene Oxide on the Growth and Photosynthesis of the Emergent Plant Iris pseudacorus.

The extensive applications of graphene oxide (GO) inevitably lead to entry into the natural aquatic environment. However, information on its toxicity to emergent plants is still lacking. In this study, an emergent plant, Iris pseudacorus, was exposed to GO (1, 20, 80, and 140 mg·L-1) under hydroponic conditions for 15 weeks. Changes in plant growth were assessed by analyzing plant biomass and photosynthetic pigment contents; the photosynthesis response was verified by measuring chlorophyll a fluorescence; and the nutrient levels of the plant were evaluated. Results showed that GO at 20-140 mg·L-1 significantly increased plant dry weight by 37-84% and photosynthetic pigment contents by 26-178%, and 80 mg·L-1 was the optimal concentration. PSII activity, adjustment capacities of electron transport in PSII, the grouping or energetic connectivity between PSII units, light energy conversion efficiency, photosynthesis performance indexes (by 11-51%), and contents of several nutrient elements (N, Fe, and Cu) were increased by 49-69%, 34-84%, and 11-38%, respectively. These findings indicate that GO can enhance plant growth by promoting plant photosynthesis performance and improving plant nutrient levels, and has great application potential in promoting the growth and development of this emergent plant as a phytoremediation agent.

Achieving improved full-spectrum responsive 0D/3D CuWO4/BiOBr:Yb3+,Er3+ photocatalyst with synergetic effects of up-conversion, photothermal effect and direct Z-scheme heterojunction

The key to obtain effective photocatalysts is to increase the efficiency of light energy conversion, and thus the design and implementation of full-spectrum photocatalysts is a potential approach to solve this problem especially by extending the absorption range to near-infrared (NIR) light. Herein, the improved full-spectrum responsive CuWO4/BiOBr:Yb3+,Er3+ (CW/BYE) direct Z-scheme heterojunction was prepared. The CW/BYE with CW mass ratio of 5% had the best degradation performance, and the removal rate of tetracycline reached 93.9% in 60 min and 69.4% in 12 h under visible (Vis) and NIR light, respectively, which were 5.2 and 3.3 times of BYE. According to the outcome of experimental, the reasonable mechanism of improved photoactivity was put forward on the basis of (i) the up-conversion (UC) effect of Er3+ ion to convert NIR photon to ultraviolet or visible light, which can be used by CW and BYE, (ii) the photothermal effect of CW to absorb the NIR light, increasing the local temperature of photocatalyst particle to accelerate the photoreaction, and (iii) the formed direct Z-scheme heterojunction between BYE and CW to boost the separation of photogenerated electron-hole pairs. Additionally, the excellent photostability of the photocatalyst was verified by cycle degradation experiments. This work opens up a promising technique for designing and synthesizing full-spectrum photocatalysts by utilizing synergetic effects of UC, photothermal effect and direct Z-scheme heterojunction.