High Recombination Rate Research Articles

Modulating the properties of g-C3N4 through two-step annealing and ionic-liquid gating

The graphitic carbon nitride (g-C3N4) is an important optoelectronic and photocatalytic material; however, its application is limited by the high recombination rate of the electron-hole (e--h+) pairs. In this work, we reported a novel strategy combining two-step annealing treatment and ionic-liquid (IL) gating technology for effectively regulating the properties of g-C3N4, especially largely reducing the recombination rate of the e--h+pairs, which is evidenced by a remarkable reduction of the photoluminescence (PL) intensity. Firstly, g-C3N4samples with typical layered structure were obtained by annealing melamine with temperature of 600 °C. Further annealing of the samples at 600 °C with much longer time (from 4 h to 12 h) were found to effectively reduce the imperfections or defects, and thus the PL intensity (49% reduction). This large reduction of PL intensity is attributed to the improved interconnection of triazine units, the shortened charge transfer diffusion distances, and the reduced interlayer spacing, which facilitate electron relocation on the g-C3N4surface. Secondly, by post-treating the annealed sample with IL, the PL intensities were found to be further reduced, mainly due to the passivation of charged defect centers by IL. Additionally, applying an external electric field in an IL environment can significantly enhance the charged defect passivation. Overall, by utilizing electric field-controlled IL gating, defect states in g-C3N4were passivated, leading to a significant reduction in PL intensity and an extension of PL lifetime, thereby effectively decreasing the e--h+recombination rate in the material. This study demonstrates a new approach for defect passivation, providing insights and strategies for modulating properties of advanced materials such as g-C3N4.

Research Progress on the GP3 Protein of Porcine Reproductive and Respiratory Syndrome Virus

Porcine reproductive and respiratory syndrome (PRRS) is a highly contagious immunosuppressive disease caused by the porcine reproductive and respiratory syndrome virus (PRRSV) that is characterized by a highly variable gene sequence and a high rate of recombination, thereby contributing to difficulties in the clinical prevention and control of this virus. Glycosylated protein 3 (GP3) is the most glycosylated protein in PRRSV, and is closely associated with the composition of PRRSV virus particles, infection, and immune evasion. This review summarizes the structural features, genetic evolutionary patterns, glycosylation of GP3 and its interactions with other PRRSV and host proteins, associations with PRRSV infection and virulence, and immunomodulatory roles. Additionally, it provides an overview of research progress on monoclonal antibodies and vaccines targeting GP3. This study aims to provide a theoretical foundation for better understanding the structure and function of GP3, of the mechanisms of PRRSV infection, and the development of novel vaccines.

Colloidal Design and Preparation of an Internal Electric Modulated Z-Scheme BiOI-CdS Heteronanostructure with Oxygen-Rich Vacancies.

Photoelectrochemical (PEC) water splitting offers an ideal strategy for the development of clean and renewable energy. However, its practical implementation is often inhibited by the high recombination rate of photogenerated charge carriers and the instability of photoanodes. Introducing defect engineering (such as oxygen vacancies) and constructing internal electric field-modulated Z-scheme heteronanostructures (HNs) can be considered as effective approaches to overcome these obstacles. Herein, a flexible method is developed for synthesizing Z-scheme BiOI-CdS HNs with oxygen vacancies, which induce an internal electric field between ultrathin BiOI nanosheets and a CdS semiconductor. This Z-scheme mechanism significantly promotes the separation of photogenerated electron-hole pairs, thereby enhancing the PEC performance. The BiOI-CdS photoanode achieves a photocurrent density of 4.22 mA cm-2 at 1.6 V vs RHE under AM 1.5G illumination (100 mW cm-2), outperforming bare BiOI and CdS. Moreover, the photoanode exhibits exceptional stability with only a slight decrease of approximately in its initial photocurrent after a rigorous 4 h test, surpassing other counterparts in terms of durability. This work affords a better understanding of oxygen vacancies and the construction of highly efficient and stable Z-scheme photoanodes for feasible PEC application.

Highly Efficient Schottky Heterojunctions for Photocatalytic Hydrogen Evolution: Facile Synthesis of Hollow Nano-ZnSe Spheres on Ti3C2-Nanosheets.

Traditional photocatalysts often have limited efficiency due to the high recombination rate of photogenerated electron-hole pairs. In this work, we synthesized 3D/2D ZnSe-MXene heterojunctions by an in situ electrostatic self-assembly method. Notably, the 3% MXene-ZnSe composite exhibited an optimized photocatalytic hydrogen production rate of 765.0 μmol g-1 h-1, about 1.6 times higher than that of pristine ZnSe. MXene's high conductivity and large surface area enhance catalytic performance by providing more active sites and efficient electron transfer pathways from ZnSe to MXene. This accelerates the separation and movement of photogenerated carriers, significantly reducing recombination. We have investigated the photocatalytic hydrogen production mechanism of the ZnSe-MXene composites using various characterization techniques. Our findings provide favourable insights into the synergistic effects within the heterojunction, offering valuable guidance for the design and development of advanced photocatalytic materials.

High-recombining genomic regions affect demography inference based on ancestral recombination graphs.

Multiple methods of demography inference are based on the ancestral recombination graph. This powerful approach uses observed mutations to model local genealogies changing along chromosomes by historical recombination events. However, inference of underlying genealogies is difficult in regions with high recombination rate relative to mutation rate due to the lack of mutations representing genealogies. Despite the prevalence of high-recombining genomic regions in some organisms, such as birds, its impact on demography inference based on ancestral recombination graphs has not been well studied. Here, we use population genomic simulations to investigate the impact of high-recombining regions on demography inference based on ancestral recombination graphs. We demonstrate that inference of effective population size and the time of population split events is systematically affected when high-recombining regions cover wide breadths of the chromosomes. Excluding high-recombining genomic regions can practically mitigate this impact, and population genomic inference of recombination maps is informative in defining such regions, yet the estimated values of local recombination rate may not be utilized for this decision. Finally, we confirm the relevance of our findings in empirical analysis by contrasting demography inferences applied for a bird species, the Eurasian blackcap (Sylvia atricapilla), using different parts of the genome with high and low recombination rates. Our results suggest that demography inference methods based on ancestral recombination graphs should be carried out with caution when applied in species whose genomes contain long stretches of high-recombining regions.

Genetic dissection of flag leaf morphology traits and fine mapping of a novel QTL (Qflw.sxau-6BL) in bread wheat (Triticum aestivum L.).

Total 60-QRC for FLM traits were detected by meta-genomics analysis, nine major and stable QTL identified by DH population and validated, and a novel QTL Qflw.sxau-6BL was fine mapped. The flag leaf is an "ideotypic" morphological trait providing photosynthetic assimilates in wheat. Although flag leaf morphology (FLM) traits had been extensively investigated through genetic mapping, there is a desire for FLM-related loci to be validated in multi-environments and fine mapping. In order to identify the stable genomic regions for FLM traits, we conducted a meta-genomic analysis based on reports from 2008 to 2024. Experimentally, a doubled haploid (DH) population was used to assess the genetic regions associated with FLM traits in nine environments. The meta-genomic analysis extracted 60 QTL-rich clusters (QRC), 45 of which were verified in marker-trait association (MTA) study. Nine major and stable QTL were found being associated with FLM traits across three-to-seven environments including BLUP, with phenotypic variance explained (PVE) ranging from 5.05 to 34.95%. The KASP markers of the nine QTL were validated (P < 0.005) in more than three environments using a panel of diverse wheat collections from Shanxi Province in China. Two co-located major and stable QTL viz. Qflw.sxau-6B.5 and Qfla.sxau-6B.4 were found novel and contributed to increaseFLW by 12.09-19.21% and FLA by 5.45-13.28%. They also demonstrated high recombination rates in LD analysis based on the resequencing of 145 wheat landmark cultivars. The fine mapping of Qflw.sxau-6BL narrowed it down to a 1.27Mb region as a result of the combined genotypic and phenotypic analysis for secondary mapping population. Comparing to NIL-ND3338, the NIL-LF5064 showed higher FLW by 20.45-27.37%, thousand-grain weight by 1.88-2.57% and grain length by 0.47-2.30% across all environments. The expression analysis of 11 tissues revealed seven highly expressed genes within the fine map region. This study provides a genetic basis for the FLM traits for further map-based cloning of FLW genes in wheat.

The adaptive value of recombination in resolving intralocus sexual conflict by gene duplication.

Recombination plays a key role in increasing the efficacy of selection. We investigate whether recombination can also play a role in resolving adaptive conflicts at loci coding for traits shared between the sexes. Errors during recombination events resulting in gene duplications may provide a long-term evolutionary advantage if those loci also experience sexually antagonistic (SA) selection since, after duplication, sex-specific expression profiles will be free to evolve, thereby reducing the load on population fitness and resolving the conflict. The potential advantage of gene duplication may be tempered by the short-term deleterious effects on gamete and zygote survival, which may be tolerable in a species with high reproductive output but not with low reproductive output. We used datasets of candidate SA loci from Drosophila melanogaster and humans to test these ideas. As in humans, sexually antagonistic alleles in flies with net positive effects across the two sexes occurred at higher frequencies than alleles with net negative effects. In flies, higher recombination rates were associated with more intense levels of sexual conflict and genes with paralogues occur in regions with higher recombination rates, indicating gene duplication events are associated with a history of SA selection. Genes experiencing higher levels of conflict also showed both a higher proportion with paralogues and higher numbers of paralogues. Together, our findings reveal multiple lines of evidence for a possible route towards the resolution of an adaptive conflict via gene duplication that is facilitated by higher recombination rates.

OPTIMIZING ELECTRON DIFFUSION, TEMPERATURE, AND PHOTOANODE THICKNESS FOR ENHANCED PHOTOVOLTAIC EFFICIENCY IN TiO₂/CuS DYE-SENSITIZED SOLAR CELLS (DSSCs)

This study addresses a critical gap in optimizing electron diffusion, operational temperature, and photoanode thickness to enhance the photovoltaic efficiency of TiO₂/CuS-doped dye-sensitized solar cells (DSSCs). While previous studies have investigated individual parameters affecting DSSC performance, limited research examines their combined effects on charge transport and recombination rates. Through computational modeling, we evaluated photoanode thicknesses from 1 µm to 100 µm and operational temperatures from 260 K to 350 K, analyzing their influence on electron mobility, recombination rates, and overall efficiency. Results show that the electron diffusion coefficient increases with temperature, reaching a maximum of 1.626 × 10⁻⁶ cm²/s at 350 K, thereby enhancing electron transport and reducing recombination losses. An optimal photoanode thickness of 3 µm was identified, yielding the highest efficiency of 17.28% across the temperature range. Efficiency declines at thicknesses exceeding 3 µm due to extended electron diffusion paths and higher recombination rates. These findings underscore the importance of balancing temperature and structural parameters to improve charge transport and minimize losses, particularly for DSSC applications in warm environments.

Noble-Metal-Free Cocatalysts Reinforcing Hole Consumption for Photocatalytic Hydrogen Evolution with Ultrahigh Apparent Quantum Efficiency.

Achieving efficient and sustainable hydrogen production through photocatalysis is highly promising yet remains a significant challenge, especially when replacing costly noble metals with more abundant alternatives. Conversion efficiency with noble-metal-free alternatives is frequently limited by high charge recombination rates, mainly due to the sluggish transfer and inefficient consumption of photo-generated holes. To address these challenges, a rational design of noble-metal-free cocatalysts as oxidative sites is reported to facilitate hole consumption, leading to markedly increased H2 yield rates without relying on expensive noble metals. By integrating femtosecond transient absorption spectroscopy with in situ characterizations and theoretical calculations, the rapid hole consumption is compellingly confirmed, which in turn promotes the effective separation and migration of photo-generated carriers. The optimized catalyst delivers an impressive photocatalytic H2 yield rate of 57.84 mmol gcat -1 h-1, coupled with an ultrahigh apparent quantum efficiency reaching up to 65.8%. Additionally, a flow-type quartz microreactor is assembled using the optimal catalyst thin film, which achieves a notable H2 yield efficiency of 0.102 mL min-1 and maintains high stability over 1260 min of continuous operation. The strategy of reinforcing hole consumption through noble-metal-free cocatalysts establishes a promising pathway for scalable and economically viable solar H2 production.

Surface Microstructure Enhanced Cryogenic Infrared Light Emitting Diodes for Semiconductor Broadband Upconversion.

Broadband upconversion has various applications in solar photovoltaic, infrared and terahertz detection imaging, and biomedicine. The low efficiency of the light-emitting diodes (LEDs) limits the broadband upconversion performance. In this paper, we propose to use surface microstructures to enhance the electroluminescence efficiency (ELE) of LEDs. Systematical investigations on the cryogenic-temperature performances of microstructure-coupled LEDs, including electroluminescence efficiency, luminescence spectrum, and recombination rate, have been carried out by elaborating their enhancement mechanism and light emitting characteristics both experimentally and theoretically. We have revealed that the reason for the nearly 35% ELE enhancement of the optimized structure under cryogenic temperature and weak injection current is the efficient carrier injection efficiency and the high recombination rate in the active region. We also compare studies of the surface luminescence uniformity of the optimized LED with that of the unoptimized device. This work gives a precise description, and explanation of the performance of the optimized microstructure coupled LED at low temperatures, providing important guidance and inspiration for the optimization of broadband upconverter in the cryogenic temperature region.

Photocatalytic Depolymerization of Lignin: C-O Bond Cleavage in β-O-4 Models Using S-Doped Ultra-Thin Bi3O4Cl Nanosheets.

The selective depolymerization of β-O-4 lignin models into high-value aromatic monomers using photocatalysis presents both significant opportunities and challenges. Photocatalysts often face issues such as high photogenerated carrier recombination rates and limited operational lifetimes. This study introduces S doping to modulate the surface interface of Bi3O4Cl (BOC) nanosheets, enhancing C-O bond cleavage efficiency in β-O-4 lignin models under visible light at ambient temperatures. Comprehensive characterization, including atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR), and density functional theory (DFT) analysis, revealed that S doping reduces BOC nanosheet thickness to 1.51 nm and promotes charge carrier separation, thereby generating greater concentrations of reactive species, specifically •O2- and •OH. Photocatalytic depolymerization experiments demonstrated that S-doped BOC achieved a C-O bond cleavage selectivity of 93% and an aromatic monomer yield of 629.03 μmol/g/h (i.e., 1.5 times higher than that of undoped BOC). This work provides a strategic approach to designing photocatalysts with enhanced selectivity and efficiency for lignin depolymerization.

Mesoporous TiO2@g-C3N4 Nanostructure-Enhanced Photocatalytic Degradation of Tetracycline Under Full-Spectrum Sunlight.

TiO2 has broad prospects in reducing the safety risks posed by emerging pollutants in water environments. However, the high recombination rate of photogenerated carriers limits the activity and photon utilization efficiency of TiO2. In this study, mesoporous TiO2 (m-TiO2) and ultra-thin g-C3N4 nanosheets were composited using a hydrothermal method, with the m-TiO2 tightly and uniformly wrapped by g-C3N4. The chemical structure, elemental composition, and optical properties of the heterojunction were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis-DRS). The activity of the m-TiO2@g-C3N4 was evaluated by the degradation of tetracycline hydrochloride (TCH). Results showed that the heterojunction exhibited significantly enhanced reactivity compared to pure m-TiO2 and g-C3N4, with kinetic rates of TCH being 1.48 and 6.84 times that of pure m-TiO2 and g-C3N4, respectively. The TCH degradation kinetic rate varied from 0.194 min-1 to 0.026 min-1 and then decreased to 0.015 min-1 on the scale of the bandgap and the number of absorbed photons in m-TiO2@g-C3N4. Concurrently, a 10wt% doping amount of g-C3N4 significantly increased the reaction rate of photogenerated carriers in the system compared to the recombination rate, corresponding to excellent photon efficiency. Reproducibility was evaluated, and a possible degradation mechanism is proposed. This study opens new perspectives for the optimization of catalyst preparation processes aimed at enhancing photon efficiency.

Enhanced Photocatalytic Nitrogen Fixation over Nano-UiO-66(Zr) via Natural Chlorophyll Sensitization.

Metal-organic frameworks (MOFs) are potential semiconductor materials, but they still face limitations, such as insufficient photoresponse, high recombination rates, and inadequate N2 adsorption/activation capabilities. Herein, a UiO-66-based system is designed via a natural chlorophyll sensitization strategy. Density functional theory calculations confirm the coordination interactions between chlorophyll and UiO-66. The chlorophyll-sensitized UiO-66 (Chlor@UiO-66) exhibits an improved NH3 production rate of 73.1 μmol g-1 h-1, compared to UiO-66 (6.3 μmol g-1 h-1). This enhancement is attributed to the dye properties of chlorophyll and the electron-donating effect of the structure, which broadens the visible light absorption range and facilitates charge carrier separation and transfer, as well as N2 adsorption/activation. In situ FT-IR characterization combined with theoretical calculations demonstrates that the reduction of N2 at the Chlor@UiO-66 surface follows the alternating hydrogenation pathway. This research provides new insights for the design and synthesis of novel natural chlorophyll-sensitized nanomaterials for the photocatalysis of small molecules.

Identification of Two Novel Recombinant Types of Potato Virus Y from Solanum tuberosum Plants in Southern Region of Russia.

Potato virus Y (PVY, genus Potyvirus, family Potyviridae) is one of the most devastating and economically important potato pathogens. Members of the Potyviridae family demonstrate high recombination rates. In nature, 5 major parental variants of PVY were identified with at least 35 recombinants. In this study we report two novel PVY recombinants discovered in the sprouts of potato tubers produced in field conditions in Astrakhan region of Russia in 2021 using high-throughput sequencing and de novo genome assembly. These recombinants, which were named Ast-A-I and Ast-A-II, have previously unknown arrangements of genome sections derived from PVYO and PVYN with a novel recombination junction at the position 7850 nt of the PVY genome, in the middle part of the RNA-dependent RNA polymerase (NIb) gene, with PVYO-type sequence at the 5'-end of this junction and PVYN-type at the 3'-end. Other recombinant junctions in the novel PVY variants were previously found in PVYNTNa and PVYNTNb. This includes those at the positions 2390 and 9200 (PVYN at the 5'-end and PVYO at the 3'-end) which were present in both novel recombinants, and at the position 500 (PVYO at the 5'-end and PVYN at the 3'-end) which present in Ast-A-II. The presence of PVY variants with novel recombinant point is verified by Sanger sequencing. Phylogenetic analysis of genomic RNA showed that the sequences of these recombinants form a separate branch which do not cluster with previously described PVY strains.

Improving visible light-driven CO2 conversion to high calorific fuels over sustainable highly crystalline and holey sulphur doped graphitic carbon nitrides

The effectiveness of CO2 reduction through g-C3N4 (CN) is considerably hindered by poor visible light absorption and the high rate of recombination of electron-hole (e−/h+) pairs. An effective method for increasing CO2 photoreduction efficiency is to incorporate non-metal components into the CN to modify its electronic properties and enhance its performance. This research presents the findings of our inquiry into sulfur-doped graphitic carbon nitrides (S–CN) for CO2 reduction through visible light. The XPS study reveals that the substitution of nitrogen atoms in the heptazine ring by sulfur (S) doping significantly influences the electronic configuration of CN, while the UV–visible absorbance spectra reveals that the CN band gap value 2.64 eV has reduced to 2.50 eV after S doping. Therefore, S–CN exhibits exceptional visible-light absorption, separation and migration of photoexcited e−/h+, corroborated by photoluminescence and transient photocurrent response experiments. Besides, S–CN demonstrated remarkable CO2 reduction capabilities without any cocatalyst or sacrificial agent, achieving CO/CH4 formation rates of 25/3 μmolg−1h−1, outperforming traditional CN. Our research highlights the relevance of impeding the e−/h+ recombination process to boost solar energy conversion output, suggesting potential for productive solar fuel generation using g-C3N4.

Oxygen vacancy enriched and Cu single-atom contained covalent organic frameworks: A competitive photocatalyst to promote hydrogen evolution under visible light

Single-atom loaded covalent organic frameworks (COFs) have been rapidly developed in the field of photocatalytic hydrogen production in recent years. Despite the insufficient active sites has been introduced, the high recombination rate of photogenerated carriers has hindered the progress of catalyst development. In this work, a novel approach is proposed to construct oxygen vacancies (OVs) on single atom Cu contained COF-TpPa, acting as an electron collector to facilitate the transfer and utilization of electrons. The Cu-OV-TpPa can provide a remarkable H2 production rate of 2.77 mmol g−1 h−1 under visible light, which is 2.6 times of Cu-P-TpPa (a H2 production rate of 1.02 mmol g−1 h−1). It achieves a high apparent quantum efficiency (AQE) of 20 % at 420 nm with no noble metal cocatalyst. A thorough analysis of carrier lifetime, recombination rate, electric conductivity and charge density reveals that the synergistic effect between OVs and single-atom Cu significantly enhances photogenerated carrier separation efficiency and reduces activation energy. This study presents a new strategy to design COF-based photocatalysts towards a competitive H2 production under visible light.

In-Situ Electrochemical Impedance Spectroscopy for Characterizing Transport Response during Material Irradiation

Radiation-induced crystalline disorder in complex oxides has a significant effect on the mass transport properties, namely the conductivity of the material. In the case of Gd2Ti2O7 (GTO) we observed that with increasing disorder, the conductivity of GTO subsequently increases. However, in the case of materials such as Yttria Stabilized Zirconia (YSZ), we observe a high radiation-tolerance to disorder and amorphization. Furthermore, the conductivity measured post-irradiation is comparable to the pristine state conductivity of YSZ. In theory, we might not see the permanent change in conductivity due to the inherent self-annealing propensity of YSZ. Such high rates of defect recombination may be masking any transport changes in the materials only present during the irradiation process. Thus, to elucidate these mass transport properties only present during irradiation we are developing an in-situ electrochemical impedance spectroscopy (EIS) method capable of experimentally probing the materials while they are undergoing irradiation.With this novel in-situ EIS method we can extract information that would otherwise be missed in the standard ex-situ EIS characterization methods. Information such as: 1) rate of increase of conductivity between the onset of irradiation until steady state is reached, 2) the magnitude of such conductivity changes under irradiation at steady state, 3) the rate of decrease of conductivity once the beam is turned off until conductivity reaches a post-irradiation steady state. Although this is especially significant for materials that are radiation resistant, extracting the rate of increase of conductivity is also relevant and interesting for materials that are not as radiation resistant such as with GTO.EIS is the preferred method for monitoring the electrical properties over other techniques such as with DC signals, because with the sinusoidal signals applied in EIS we extract these time-scale properties which make it possible to separate transport resistances from other rate-limiting processes. For the development of in-situ EIS: conductivity pathways, electrode geometries, beam path to the material, operating parameters of the potentiostat, and other considerations were made. Preliminary results for YSZ show that in the relatively lower operating temperature of 300 °C (far below the optimal temperature for high conductivity) the conductivity significantly increases when the irradiation beam is turned on, and quickly reverts to initial conductivity levels when the beam is turned off. Major contributions to the conductivity changes are attributed to the point defects created during the irradiation process. Thermal contributions of the beamline are excluded as the major contributor when comparing the temperature expected to reach the magnitude of conductivity change as well as the rate of decrease when the initial state of YSZ conductivity is recovered. Figure 1. A) Electrode design used in preliminary experiments. B) Embedded electrode design for controlled area for more accurate conductivity calculations. C) Array of electrode geometries to optimize fabrication of embedded electrodes. D) Generalized example of ex-situ conductivity data. E) Generalized example of in-situ conductivity data. Figure 1

Utilization of Waste Melamine Formaldehyde Resin As an Enhancer in g-C3N4 Photocatalyst and Photoelectrochemical Applications

Melamine Formaldehyde resin (MF), one of the thermoset plastic frequently used for cook wares, adhesive, insulator and coatings because of its thermostability, mechanical strength, electronic insulation and ease of manufacture. However, because of above properties of MF resin, it is hard to recycle after used, which causes serious environmental contamination. To overcome this drawback of after-used MF resin, we introduce a method on utilizing after-used MF resin for an enhancer of g-C3N4 photocatalyst, inspired by pristine methodologies to synthesize g-C3N4 photocatalyst.The pristine g-C3N4 photocatalyst is synthesized by heat polymerization of urea, dicyandiamide(DCDA) and melamine and it utilize widely as a photocatalytst because it has a suitable band gap for visible light absorption, high chemical stability, and high thermal stability. However, high electron-hole recombination rate of g-C3N4 photocatalyst regarded as the reason decreases photocatalytic activity of g-C3N4 photocatalyst.Therefore, in this study, after-used MF resin as an enhancer during g-C3N4 photocatalyst syntehsis process, to improve photocatalytic activity of g-C3N4. The pure g-C3N4 photocatalyst was synthesized by heat polyemrization of urea and MF resin added g-C3N4 photocatalyst (MR X, X is the amount of added MF resin) was synthesized by adding certain amount of MF resin during g-C3N4 synthesis process. Comparing photocatalytic activity between pure g-C3N4 and MR photocatalyst was carried out by Methyl Orange (MO) degradation under 1 sun illumination. Finally, pure g-C3N4 and MR photocatalyst was fabricated as an photoelectrode and their oxygen evolution reaction(OER) activity was analyzed by electrochemical analysis techniques.

(Invited) Titanium Dioxide Photocatalyst Treated by in-Liquid Plasma and Its Application in Environmental Purification

Titanium dioxide (TiO2) has been widely investigated as photocatalyst because of its environmentally and economically advantages with high chemical stability, earth abundant and biocompatible properties. However, its large band gap for the activity to only UV light region, and the high recombination rate of photogenerated electron and hole pairs have to be overcome to utilize effectively sunlight, and to enhance the photocatalytic performance. Recent enormous efforts to overcome the above-mentioned drawbacks have resulted in the one-dimensional TiO2 nanotubes, nanofibers and nanorods to suppress the carrier recombination, and/or the heterojunction structure of TiO2 with another semiconductor to achieve larger separation of the photogenerated electron and hole, as well as the modification of TiO2 nanoparticles with gold clusters to expand the light conversion from UV to visible and near-infrared region. Another interesting approach on black TiO2 nanoparticles succeeded in narrowing the band gap of pure white TiO2 nanoparticles, however, it required the hard treatment condition of a 2 MPa hydrogen atmosphere at ca. 200 °C for 5 days (X. Chen, et al., Science, 331 (2011) 746). In order to synthesize the hydrogenated TiO2 nanoparticles, the thermal treatment under hydrogen and plasma treatment have mostly relied on the reduction of TiO2 nanoparticles. But, these processes have drawbacks such as high temperature over 1,000 °C, vacuum system for hydrogen plasma and long treatment time. After thermal treatment, the sintered nanoparticles should be crush to follow multistep processes. Thus, alternative approaches have been highly demanded in the reduction of TiO2 with keeping its nano-sized particle.On the other hand, non-equilibrium plasma, in which the electron temperature is very high and deviates from the ion temperature, is an attractive reaction field because it can achieve low temperature processes in material synthesis and other applications. In particular, when plasma is generated in a liquid, reaction processes below the boiling point of the liquid become possible, and a special reaction field can be expected to be formed. In a so-called solution plasma using a bipolar pulse power supply (O. Takai, Pure Appl. Chem., 80 (2008) 2003), the solvent was water, and plasma was generated in an air-fed environment within solvent. Therefore, the surface modification of TiO2 nanoparticles in a solution plasma reaction field to introduce oxygen vacancy on the sub-surface while maintaining the nano-size has succeeded in improving photocatalytic activity (S. Pitchaimuthu, C. Terashima et al., ACS Omega 3 (2018) 898). The present study focused to treat pristine TiO2 nanoparticles by the discharge in water-based solution and to investigate the material properties as well as the photocatalytic activities for decomposing organics.

Chromosome-level genome assemblies and genetic maps reveal heterochiasmy and macrosynteny in endangered Atlantic Acropora

BackgroundOver their evolutionary history, corals have adapted to sea level rise and increasing ocean temperatures, however, it is unclear how quickly they may respond to rapid change. Genome structure and genetic diversity contained within may highlight their adaptive potential.ResultsWe present chromosome-scale genome assemblies and linkage maps of the critically endangered Atlantic acroporids, Acropora palmata and A. cervicornis. Both assemblies and linkage maps were resolved into 14 chromosomes with their gene content and colinearity. Repeats and chromosome arrangements were largely preserved between the species. The family Acroporidae and the genus Acropora exhibited many phylogenetically significant gene family expansions. Macrosynteny decreased with phylogenetic distance. Nevertheless, scleractinians shared six of the 21 cnidarian ancestral linkage groups as well as numerous fission and fusion events compared to other distantly related cnidarians. Genetic linkage maps were constructed from one A. palmata family and 16 A. cervicornis families using a genotyping array. The consensus maps span 1,013.42 cM and 927.36 cM for A. palmata and A. cervicornis, respectively. Both species exhibited high genome-wide recombination rates (3.04 to 3.53 cM/Mb) and pronounced sex-based differences, known as heterochiasmy, with 2 to 2.5X higher recombination rates estimated in the female maps.ConclusionsTogether, the chromosome-scale assemblies and genetic maps we present here are the first detailed look at the genomic landscapes of the critically endangered Atlantic acroporids. These data sets revealed that adaptive capacity of Atlantic acroporids is not limited by their recombination rates. The sister species maintain macrosynteny with few genes with high sequence divergence that may act as reproductive barriers between them. In the Atlantic Acropora, hybridization between the two sister species yields an F1 hybrid with limited fertility despite the high levels of macrosynteny and gene colinearity of their genomes. Together, these resources now enable genome-wide association studies and discovery of quantitative trait loci, two tools that can aid in the conservation of these species.