Electron Acceptor Research Articles

Identification of bacterial dissimilatory antimonate reductase AnrA: genes and proteins involved in antimonate respiration and resistance in Geobacter sp. strain SVR.

Geobacter sp. strain SVR uses antimonate [Sb(V)] as a terminal electron acceptor for anaerobic respiration. Here, we visualized a possible key enzyme, periplasmic Sb(V) reductase (Anr), via active staining and non-denaturing gel electrophoresis. Liquid chromatography-tandem mass spectrometry analysis revealed that a novel dimethyl sulfoxide (DMSO) reductase family protein, WP_173201954.1, is involved in Anr. This protein was closely related with AnrA, a protein suggested to be the catalytic subunit of a respiratory Sb(V) reductase in Desulfuribacillus stibiiarsenatis. The anr genes of strain SVR (anrXSRBAD) formed an operon-like structure, and their transcription was upregulated under Sb(V)-respiring conditions. The expression of anrA gene was induced by more than 1 µM of antimonite [Sb(III)]; however, arsenite [As(III)] did not induce the expression of anrA gene. Tandem mass tag-based proteomic analysis revealed that, in addition to Anr proteins, proteins in the following categories were upregulated under Sb(V)-respiring conditions: (i) Sb(III) efflux systems such as Ant and Ars; (ii) antioxidizing proteins such as ferritin, rubredoxin, and thioredoxin; (iii) protein quality control systems such as HspA, HslO, and DnaK; and (iv) DNA repair proteins such as UspA and UvrB. These results suggest that strain SVR copes with antimony stress by modulating pleiotropic processes to resist and actively metabolize antimony. To the best of our knowledge, this is the first report to demonstrate the involvement of AnrA in Sb(V) respiration at the protein level. Furthermore, this is the first example to show high expression of the Ant system proteins in the Sb(V)-respiring bacterium.IMPORTANCEAntimony (Sb) exists mainly as antimonite [Sb(III)] or antimonate [Sb(V)] in the environment, and Sb(III) is more toxic than Sb(V). Recently, microbial involvement in Sb redox reactions has received attention. Although more than 90 Sb(III)-oxidizing bacteria have been reported, information on Sb(V)-reducing bacteria is limited. Especially, the enzyme involved in dissimilatory Sb(V) reduction, or Sb(V) respiration, is unclear, despite this pathway being very important for the circulation of Sb in nature. In this study, we demonstrated that the Sb(V) reductase (Anr) of an Sb(V)-respiring bacterium (Geobacter sp. SVR) is a novel member of the dimethyl sulfoxide (DMSO) reductase family. In addition, we found that strain SVR copes with Sb stress by modulating pleiotropic processes, including the Ant and Ars systems, and upregulating the antioxidant and quality control protein levels. Considering the abundance and diversity of putative anr genes in the environment, Anr may play a significant role in global Sb cycling in both marine and terrestrial environments.

Recent Advances in Selenium‐Containing Non‐fullerene Acceptors for High‐Performance Organic Solar Cells

AbstractThe diversity in molecular structures and solution processability of non‐fullerene acceptors (NFAs), particularly those containing selenium (Se), plays a pivotal role in advancing organic solar cells (OSCs). Among various molecular design strategies, the introduction of selenium atoms, characterized by their large covalent radius, loose electron cloud, and strong polarization properties, can enhance intermolecular Se‐Se interactions and improve the electron‐donating capability of π‐cores. This approach is considered a significant avenue for optimizing the photovoltaic performance of active layer materials. In this review, we provide a comprehensive summary of recent advancements in selenium‐containing acceptor molecules. These include ITIC‐based fused ring NFAs, Y6‐based fused ring NFAs, Y6‐based polymer acceptors, non‐fused ring electron acceptors and their application in tandem and ternary OSCs. Additionally, we analyze the future prospects and development of selenium‐containing NFAs with the goal of achieving OSC efficiencies exceeding 20 %.

Probing the effects of gold doping on structural, electronic and nonlinear optical properties of caged X20H20 (X=Si, Ge, Sn, Pb) clusters

AbstractCarbon family elements (Si, Ge, Sn, Pb) have attracted a lot of attention because of their unique structural features and potential applications in microelectronics industry. Here, the structure, chemical stability, electronic properties, and nonlinear optical properties of neutral and charged Au@X20H20 (X=Si, Ge, Sn, Pb) clusters have been systematically studied using density‐functional theory calculations. Structurally, the neutral/anionic Au@X20H20 (X=Si, Ge, Sn) as well as cationic Au@Pb20H20 possess Au‐endohedral (XH)20 unit, forming fullerene‐like framework, whereas other species are Au‐doped structures with hydrogen‐bridged bond. Analysis of binding energy and HOMO‐LUMO energy gaps reveals that the charged clusters possess high chemical stabilities due to closed‐shell structures. The charge transfers from X20 cage to Au atom, and the Au atom acts as electron acceptor. The Au atom and charged states play an important role in the structural stability, and can effectively modulate the electronic properties of clusters. Interestingly, the neutral Au@X20H20 (X=Si, Sn) clusters possess large first hyperpolarizabilities, especially for Au@Sn20H20, which has remarkably giant value (~5.65×108 a. u.), and the enhanced NLO behaviors can be further explained by the TDDFT calculation. The work may provide a theoretical reference for further applications considered as novel cluster‐assembled nanomaterials.

Ecological determinants of 17α-ethynylestradiol biodegradation: Unveiling unique microbial community assemblages in lake sediments under nitrate or sulfate reduction

Nitrate and sulfate, as electron acceptors (EAs), influence microbial communities and the subsequent biodegradation of emerging contaminants, such as 17α-ethynylestradiol (EE2) in anaerobic sediments. Results of this study showed that nitrate amendment significantly raised nitrate reduction intensity within a short period (<5 days) and greatly influenced microbial community succession compared with sulfate amendment. Nitrate reduction induced deterministic selections that narrowed the niche widths of the microbial community, creating direct correlations between functional members, including denitrifiers and potential estrogen degraders like Pseudomonas. The facilitative coordination of microbes and increased denitrification resulted in greater EE2 biodegradation under nitrate-reducing (0.19 ± 0.02 μg g−1) and combined nitrate- and sulfate-reducing conditions (0.23 ± 0.01 μg g−1) after 120 days. Moreover, natural organic matter enhanced interspecies syntrophic cooperation (the number of direct connectors increased from 9 to 25 in the microbial network) in the microbial community and further improved EE2 biodegradation efficiency to 0.26 ± 0.03 μg g−1. Conversely, sulfate reduction required longer adaptation (>20 days) with a higher contribution of stochastic processes in community assembly, yielding fewer connections with estrogen degraders and weaker EE2 biodegradation (0.15 ± 0.03 μg g−1). These mechanistic understandings can guide EA selection in the bioremediation of emerging contaminants.

Nitrate increases the capacity of an aerobic moving-bed biofilm reactor (MBBR) for winery wastewater treatment.

We used bench-scale tests and mathematical modeling to explore chemical oxygen demand (COD) removal rates in a moving-bed biofilm reactor (MBBR) for winery wastewater treatment, using either urea or nitrate as a nitrogen source. With urea addition, the COD removal fluxes ranged from 34 to 45 gCOD/m2-d. However, when nitrate was added, fluxes increased up to 65 gCOD/m2-d, twice the amount reported for aerobic biofilms for winery wastewater treatment. A one-dimensional biofilm model, calibrated with data from respirometric tests, accurately captured the experimental results. Both experimental and modelling results suggest that nitrate significantly increased MBBR capacity by stimulating COD oxidation in the deeper, oxygen-limited regions of the biofilm. Our research suggests that the addition of nitrate, or other energetic and broadly used electron acceptors, may provide a cost-effective means of covering peak COD loads in biofilm processes for winery or another industrial wastewater treatment.

Reinforced photogenerated electron convergence on graphdiyne(g-CnH2n-2) “as an active site and substrate” for enhance photocatalytic hydrogen production

Graphdiyne(GDY), as a carbon-based catalyst with tunable electronic structure, has a significant impact on the advancement of sustainable photocatalytic technology. Its tunable electronic structure can effectively regulate the activity and selectivity of photocatalytic reaction. In this paper, GDY was prepared by a new method of ball milling HEB-TMS, and CoWO4 nanoparticles were uniformly loaded on the surface of GDY to construct a Type-II heterojunction. GDY provides a dispersed and effective substrate for CoWO4, forming a closer contact interface. Based on GDY's unique electronic structure and the formation of Type-II heterojunction, GDY/CoWO4 enhances the separation of photoexcited electrons and holes, thus increasing the electron cloud density on GDY. As an electron acceptor and active site for hydrogen production, GDY promotes the proton reduction reaction. In addition, the charge transfer process of GDY/CW-15 was demonstrated by in-situ XPS and UPS, and the corresponding hydrogen production mechanism was proposed. This study provides a facile and efficient method for preparing GDY and a new idea for heterojunction photocatalyst based on GDY substrate.

Asymmetric empty orbitals in ZrO2-BCN for enhancing electrocatalytic hydrogenation of nitrogen to ammonia

Electrocatalytic nitrogen reduction reaction (NRR) provides an environment-friendly and sustainable approach for nitrogen fixation at ambient conditions. However, simultaneously activating N≡N triple bond and suppressing the competitive hydrogen evolution reaction (HER) in aqueous electrolytes remain challenges. Herein, we construct ZrO2-BCN hetero-catalyst with tunable Zr-B-N interfacial structure for efficiently improving selectivity of the NRR. The asymmetric electron acceptance and back-donation capacity of the empty orbitals of Zr and B favors the activation of the N≡N triple bond during the NRR. The optimal ZrO2-BCN catalyst exhibits excellent NRR performance with a high ammonia yield of 17.8 μg mg-1cat. h−1 at −0.65 V vs. reversible hydrogen electrode (RHE) and a faradaic efficiency of 23.1 % at −0.45 V vs. RHE in 0.1 M HCl electrolyte, surpassing most previous reports. In-situ electrochemical attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy demonstrates the effect of the Zr-B-N interface on activating N2. This study paves a new way for hetero-interface catalyst design that would accelerate the implementation of NRR technology.

Modeling the Interaction between the Isoniazid Anti-Tuberculosis Drug and Functionalized Carbon Nanotubes for Medical Applications: A Quantum Chemical Study

Introduction: The purpose of using nano-carriers for drugs delivery, such as nanotubes, was slow release of drug and reducing side effects of drugs. Drugs are very active due to their many functional groups. Therefore, reactivity of drug is reduced by being in nanotube field due to electronic resonance of drug with nanotube and it stays longer in body. The present study aimed to investigate the interaction of isoniazid with functionalized single-walled carbon nanotubes.&#x0D; Methods: In the present theoretical study, considering the importance of isoniazid as the first line of treatment for tuberculosis disease, the performance of carbon nanostructures for adsorption of isoniazid was evaluated using quantum computation. Using density functional theory at theoretical level of B3LYP/6-31G** structure of drug and f-SWCNT and nano-drug complexes were optimized.&#x0D; Results: Effect of adsorption on the electronic properties and stability of the nanotube was also examined. In this regard, for different configurations, the strength and nature of intermolecular interactions were evaluated by energy parameters and molecular orbitals. Based on the obtained results, a specific configuration displayed the most negative adsorption energy and enthalpy, establishing itself as the most stable structure among the various configurations.&#x0D; Conclusion: Results showed that the electron density of the HOMO (Highest Occupied Molecular Orbital) was localized on the nanotube, while the electron density of the LUMO (Lowest Unoccupied Molecular Orbital) was situated on the drug molecule. The energy gap between two molecular orbitals increased due to the adsorption process; changes lead to an increase in the electrical conductivity of the complex following adsorption. According to the natural bond orbitals, results, the isoniazid molecule and functionalized single-walled carbon nanotube act as both electron donor and acceptor in the complex. Analysis of the results obtained from quantum theory of atoms in molecules, showed the intermolecular interaction between the drug and the functional group of the nanotube has been established, the most important of which is the hydrogen bond. Finally, the findings showed that functionalized SWCNTs can be acted as a drug carrier for isoniazid anti-tuberculosis drug.&#x0D;

Visible light-driven TiO2-WO3@GO photocatalyst with catalytic memory for round-the-clock photocatalytic degradation of oilfield-produced water

The inability of most photocatalysts to continue the catalytic process after the removal of light irradiation is one of their major drawbacks. In this work, a ternary nanocomposite of titanium oxide (TiO2) supported with tungsten oxide (WO3) and hybridized with graphene oxide (GO) (TiO2-WO3@GO) photocatalyst with electron energy storage properties was synthesized for oilfield-produced water (OPW) treatment under visible light and in dark conditions. WO3 addition extended the light absorption range of TiO2 into the visible light while also serving as an electron storage material for dark catalysis (memory catalysis). The GO serves as an efficient electron acceptor and transporter to prevent charge carrier recombination, thereby enhancing interfacial electron transfer within the photocatalyst system. 2.5 wt%, 5 wt%, and 10 wt% of WO3 precursors were reacted with TiO2 precursor and GO was further added to synthesize the nanocomposites via a modified sol-gel and solution-based approach for the first time. The properties of the nanocomposite were assessed using a wide range of characterization. The nanocomposite containing 5 wt% WO3 showed the best photocatalytic activity with the total organic content (TOC) degradation of 27.7% within 4 h of photodegradation in visible light, which is better than 22 % in 5 h under UV light so far reported in the literature. The nanocomposite also exhibited electron energy storage properties for dark catalysis after pre-illumination, i.e., 16.6% TOC degradation in 3 h in dark conditions. This low % TOC degradation in the dark could be attributed to the complex nature of OPW. This work has further confirmed the possibility of the use of photocatalysts for dark catalysis.

Thermodynamic Inhibition of Microbial Sulfur Disproportionation in a Multisubunit Designed Sulfur-Siderite Packed Bioreactor.

Sulfur disproportionation (S0DP) poses a challenge to the robust application of sulfur autotrophic denitrification due to unpredictable sulfide production, which risks the safety of downstream ecosystems. This study explored the S0DP occurrence boundaries with nitrate loading and temperature effects. The boundary values increased with the increase in temperature, exhibiting below 0.15 and 0.53 kg-N/m3/d of nitrate loading at 20 and 30 °C, respectively. A pilot-scale sulfur-siderite packed bioreactor (150 m3/d treatment capacity) was optimally designed with multiple subunits to dynamically distribute the loading of sulfur-heterologous electron acceptors. Operating two active and one standby subunit achieved an effective denitrification rate of 0.31 kg-N/m3/d at 20 °C. For the standby subunit, involving oxygen by aeration effectively transformed the facultative S0DP functional community from S0DP metabolism to aerobic respiration, but with enormous sulfur consumption resulting in ongoing sulfate production of over 3000 mg/L. Meanwhile, acidification by the sulfur oxidation process could reduce the pH to as low as 2.5, which evaluated the Gibbs free energy (ΔG) of the S0DP reaction to +2.56 kJ, thermodynamically suppressing the S0DP occurrence. Therefore, a multisubunit design along with S0DP inhibition strategies of short-term aeration and long-term acidification is suggested for managing S0DP in various practical sulfur-packed bioreactors.

A Novel Non-Fullerene D-A Interface with Two Asymmetrical Electron Acceptors Facilitates Charge and Energy Transfer for Effective Carbon Dioxide Reduction.

Converting carbon dioxide (CO2 ) into high-value chemicals using solar energy remains a formidable challenge. In this study, the CSC@PM6:IDT6CN-M:IDT8CN-M non-fullerene small-molecule organic semiconductor is designed with highly efficient electron donor-acceptor (D-A) interface for photocatalytic reduction of CO2 . Atomic Force Microscope and Transmission Electron Microscope images confirmed the formation of an interpenetrating fibrillar network after combination of donor and acceptor. The CO yield from the CSC@PM6:IDT6CN-M:IDT8CN-M reached 1346µmolg-1 h-1 , surpassing those of numerous reported inorganic photocatalysts. The D-A structure effectively facilitated charge separation to enable electrons transfer from the PM6 to IDT6CN-M:IDT8CN-M. Meanwhile, attributing to the dipole moments of the strong intermolecular interactions between IDT6CN-M and IDT8CN-M, the intermolecular forces are enhanced, and laminar stacking and π-π stacking are strengthened, thereby reinforcing energy transfer between acceptor molecules and significantly enhanced charge separation. Moreover, the strong internal electric field in the D-A interface enhanced the excited state lifetime of PM6:IDT6CN-M:IDT8CN-M. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis demonstrated that carboxylate (COOH*) is the predominant intermediate during CO2 reduction, and possible pathways of CO2 reduction to CO are deduced. This study presents a novel approach for designing materials with D-A interface to achieve high photocatalytic activity.

Recycling alkali lignin-derived biochar with adsorbed cadmium into cost-effective CdS/C photocatalyst for methylene blue removal.

Cadmium (Cd)-enriched adsorbents wastes possess great environmental risk due to their large-scale accumulation and toxicity in the natural environment. Recycling spent Cd-enriched adsorbents into efficient catalysts for advanced applications could address the environmental issues and attain the carbon neutral goal. Herein, a facile strategy is developed for the first time to reutilize the alkali lignin (AL)-derived biochar (ALB) absorbed with Cd into cadmium sulphide (CdS)/C composite for the efficient methylene blue (MB) removal. The ALB is initially treated with Cd-containing solution, then the recycling ALB samples with adsorbed Cd are converted to the final CdS/C composite using NaS2 as the sulphurizing reagent for vulcanization reaction. The optimal ALB400 demonstrates a high adsorption capacity of 576.0 mg g-1 for Cd removal. Then the converted CdS/C composite shows an efficient MB removal efficiency of 94%. The photodegradation mechanism is mainly attributed to carbon components in the CdS/C composite as electron acceptor promoting the separation of photoelectrons/holes and slowing down the abrasion of CdS particles. The enhanced charge transfer and contact between the carrier and the active site thus improves the removal performance and reusability. This work not only develops a method for removing Cd from wastewater effectively and achieving the waste resource utilization but also further offers a significant guidance to use other kinds of spent heavy metal removal adsorbents for the construction of low-cost and high value-added functional materials.

The energy-converting hydrogenase Ech2 is important for the growth of the thermophilic acetogen Thermoanaerobacter kivui on ferredoxin-dependent substrates.

Acetogens thrive by converting H2+CO2 to acetate. Under environmental conditions, this allows for only very little energy to be conserved (∆G'<-20 kJ mol-1). CO2 serves as a terminal electron acceptor in the ancient Wood-Ljungdahl pathway (WLP). Since the WLP is ATP neutral, energy conservation during growth on H2 + CO2 is dependent on the redox metabolism. Two types of acetogens can be distinguished, Rnf- and Ech-type. The function of both membrane-bound enzyme complexes is twofold-energy conversion and redox balancing. Ech couples the Fd-dependent reduction of protons to H2 to the formation of a proton gradient in the thermophilic bacterium Thermoanaerobacter kivui. This bacterium may be utilized in gas fermentation at high temperatures, due to very high conversion rates and the availability of genetic tools. The physiological function of an Ech hydrogenase in T. kivui was studied to contribute an understanding of its energy and redox metabolism, a prerequisite for future industrial applications.

Tailoring the Electron‐Deficient Central Core on Fused‐Ring Nonfullerene Acceptors: Deciphering the Relationships Between Structure, Property, and Photovoltaic Performance

In the field of organic solar cells, organic semiconductors with Y6‐based chemical structure and their corresponding quinoxaline‐based assemblies are settled down as promising materials in the field of OSCs. However, the chemical structure of Y6 derivatives does not allow an expansion in the electron‐withdrawing central core, in contrast to their quinoxaline‐based analogues. For this reason, herein, two different quinoxaline‐based A–D–A′–D–A derivatives with 2D π‐extended cores endowed with electroactive rylenimide moieties, named as Y6‐1Napht and Y6‐1Pery, are designed and synthesized. These enlarged fused‐ring electron acceptors (FREAs) allow to study the influence of the length of the ryleneimide moiety on its structural, optical, electrochemical, and thermal properties as well as the tailoring of the frontier molecular orbitals. These results are also supported by quantum chemical calculations and photoluminescence measurements that provide additional information about their thermal stability and the microstructure of the films. Finally, as a proof of concept and to study the influence of these chemical modifications on the central core, solar cells based on these π‐conjugated nonfullerene acceptors are fabricated.

Deep groundwater irrigation altered microbial community and increased anammox and methane oxidation in paddy wetlands of Sanjiang Plain, China.

The over-utilizing of nitrogen fertilizers in paddy wetlands potentially threatens to the surrounding waterbody, and a deep understanding of the community and function of microorganisms is crucial for paddy non-point source pollution control. In this study, top soil samples (0-15 cm) of paddy wetlands under groundwater's irrigation at different depths (H1: 6.8 m, H2: 13.7 m, H3: 14.8 m, H4: 15.6 m, H5: 17.0 m, and H6: 17.8 m) were collected to investigate microbial community and function differences and their interrelation with soil properties. Results suggested some soil factor differences for groundwater's irrigation at different depths. Deep-groundwater's irrigation (H2-H6) was beneficial to the accumulation of various electron acceptors. Nitrifying-bacteria Ellin6067 had high abundance under deep groundwater irrigation, which was consistent with its diverse metabolic capacity. Meanwhile, denitrifying bacteria had diverse distribution patterns. Iron-reducing bacteria Geobacter was abundant in H1, and Anaeromyxobacter was abundant under deep groundwater irrigation; both species could participate in Fe-anammox. Furthermore, Geobacter could perform dissimilatory nitrate reduction to ammonia using divalent iron and provide substrate supply for anammox. Intrasporangium and norank_f_Gemmatimonadacea had good chromium- and vanadium-reducting potentials and could promote the occurrence of anammox. Low abundances of methanotrophs Methylocystis and norank_f_Methyloligellaceae were associated with the relatively anoxic environment of paddy wetlands, and the presence of aerobic methane oxidation was favorable for in-situ methane abatement. Moisture, pH, and TP had crucial effects on microbial community under phylum- and genus-levels. Microorganisms under shallow groundwater irrigation were highly sensitive to environmental changes, and Fe-anammox, nitrification, and methane oxidation were favorable under deep groundwater irrigation. This study highlights the importance of comprehensively revealing the microbial community and function of paddy wetlands under groundwater's irrigation and reveals the underlying function of indigenous microorganisms in agricultural non-point pollution control and greenhouse gas abatement.

Planar Chiral Thermally Activated Delayed Fluorescence Materials Based on Di[2.2]paracyclophane for Circularly Polarized Electroluminescence

AbstractIn this study, featuring di[2.2]paracyclophane (DpCp) amine derivatives as electron donors and 4‐(4,6‐diphenyl‐1,3,5‐triazin‐2‐yl)phenyl (Trz) as the electron acceptor, four thermally activated delayed fluorescence (TADF) molecules are disclosed. The C2 symmetric molecules, DpCpN‐Trz and DpCpCz‐Trz, bearing a chair‐like planar chiral di[2.2]paracyclophane moiety, are obtained as optically pure enantiomers (R/S)‐C‐DpCpN‐Trz and (R/S)‐C‐DpCpCz‐Trz. And the compounds B‐DpCpN‐Trz and B‐DpCpCz‐Trz with a bridge‐like di[2.2]paracyclophane skeleton are meso‐compounds, thus without optically activity. All emitters show blue emissions peaking from 464 to 485 nm, accompanied by high photoluminescence quantum efficiency (up to 93%). The enantiomers (R/S)‐C‐DpCpN‐Trz and (R/S)‐C‐DpCpCz‐Trz exhibit symmetric circularly polarized photoluminescence spectra with dissymmetry factors (|gPL|) ranging from 3.8 × 10−4 to 6.7 × 10−4 in toluene and films. The organic light‐emitting diodes (OLEDs) fabricated with these emitters achieve maximum external quantum efficiencies of up to 19.5%. Notably, the circularly polarized OLEDs (CP‐OLEDs) with (R/S)‐C‐DpCpN‐Trz and (R/S)‐C‐DpCpCz‐Trz demonstrate |gEL| factors of up to 7.6 × 10−4. This study demonstrates a feasible way to design TADF materials and enantiomers by incorporating DpCp derivatives for CP‐OLEDs.

Nitrate radical formation and reaction with limonene by TiO2 photocatalysis: A kinetic study

The oxidative cleavage and the epoxidation of the endocyclic double bond of limonene can be performed in irradiated suspensions of TiO2 because of the formation of nitrate radical species deriving from the hole-induced oxidation of nitrate ions. The reaction is boosted by electron acceptors such as silver ions or in the presence of silver nanoparticles at the surface of TiO2. A thorough kinetic analysis of the reaction performances under several experimental conditions provided a set of kinetic constants, which characterise the elementary steps of this complex reaction. In particular, for the first time an evaluation of the kinetics of the formation of nitrate radicals in heterogeneous photocatalysis has been provided. Moreover, the effect of silver ions in solution and of silver nanoparticles at the surface of TiO2 could be quantitatively estimated. The developed set of kinetic equations satisfactorily predict the experimental data under several experimental conditions and can be used as the starting point of reactor design activities, in view of a future scale-up of the process. Moreover, the successful fitting of the model corroborates the proposed reaction mechanism, and provides fundamental insights on the elementary reaction steps.

Nickel phosphide cocatalyst and carbon defects simultaneously boosting the photocatalytic hydrogen production over carbon nitride

The suppression of photogenerated carrier recombination in carbon nitride and the consequent enhancement of its photocatalytic hydrogen evolution performance have emerged as a research hotspot in the field of photocatalysis. Herein, Nickel phosphide (Ni2P) was anchored onto carbon nitride with carbon defects through a synthesis involving thermal polymerization and photoreduction. The existence of carbon defects derived from the rupture of carbon nitride (CN) heterocycles were beneficial to strengthening optical absorption and the separation capabilities of photogenerated carriers. Furthermore, Ni2P cocatalysts could serve as electron acceptors that effectively accelerate the transfer and transport capabilities of the photogenerated charge carriers. Consequently, the 7 wt% Ni2P/CNN photocatalyst achieved a maximum hydrogen evolution rate of 2062 μmol·g−1·h−1, which was 7.8 times and 6.2 times greater than that of Ni2P/CN and Ni/CNN, respectively, and was comparable to the rate achieved by 3 wt% Pt/CNN. This result was comparable or even better than those reported previously. Our work provided a simply strategy for developing non-precious metal-based nickel phosphide photocatalysts for renewable solar-driven photocatalytic hydrogen production.

Dual fluorescence induced thermally activated delayed fluorescence materials based on 2,4-Diphenylthieno[3,2-d]pyrimidine with an efficient single-molecular white electroluminescence

Dual fluorescence compounds exhibit a wide emission spectrum in visible-light range and show huge application prospect in white-light OLED (WOLED). However, few of them can realize the trade-off between high color purity of white-light emission and high emission efficiency. In this work, using sulfur atom-fused electron acceptor (A) unit 2,4-diphenylthieno[3,2-d]pyrimidine (TP) and planar electron donor (D) unit phenothiazine (PTZ), a series of novel dual fluorescence compounds with simple twisting D-A configuration were designed and synthesized, denoted as PTZ-2TP, PTZ-4TP and DPTZ-TP, respectively. Simultaneous dual fluorescence emission could be realized both solution and film state of the current system via optimizing polarization environment and doped concentration, which are attributed to the characteristic quasi-axial (QA) and quasi-equal (QE) conformations. Subsequently, these compounds were successfully applied in WOLED with high efficiency. DPTZ-TP as emitter endows the WOLED with the best device performance with greenish-white light emission, CIE coordinates of (0.33, 0.44) and high EQEmax of 11.87%, which is the highest records of such single compound systems.

Molecular Serum Albumin Unmask Nanobio Properties of Molecular Graphenes in Shungite Carbon Nanoparticles.

Serum albumin is a popular macromolecule for studying the effect of proteins on the colloidal stability of nanoparticle (NP) dispersions, as well as the protein-nanoparticle interaction and protein corona formation. In this work, we analyze the specific conformation-dependent phase, redox, and fatty acid delivery properties of bovine albumin in the presence of shungite carbon (ShC) molecular graphenes stabilized in aqueous dispersions in the form of NPs in order to reveal the features of NP bioactivity. The formation of NP complexes with proteins (protein corona around NP) affects the transport properties of albumin for the delivery of fatty acids. Being acceptors of electrons and ligands, ShC NPs are capable of exhibiting both their own biological activity and significantly affecting conformational and phase transformations in protein systems.