Oxygen‑Coordinated Single Mn Sites for Efficient Electrocatalytic Nitrate Reduction to Ammonia

Electrocatalytic nitrate reduction reaction has attracted increasing attention due to its goal of low carbon emission and environmental protection.Here,we report an efficient NitRR catalyst composed of single Mn sites with atomically dispersed oxygen(O)coordination on bacterial cellulose-converted graphitic carbon(Mn-O-C).Evidence of the atomically dispersed Mn-(O-C_(2))_(4)moieties embedding in the exposed basal plane of carbon surface is confirmed by X-ray absorption spectroscopy.As a result,the as-synthesized Mn-O-C catalyst exhibits superior NitRR activity with an NH_(3)yield rate(RNH_(3))of 1476.9±62.6μg h^(−1)cm^(−2)at−0.7 V(vs.reversible hydrogen electrode,RHE)and a faradaic efficiency(FE)of 89.0±3.8%at−0.5 V(vs.RHE)under ambient conditions.Further,when evaluated with a practical flow cell,Mn-O-C shows a high RNH_(3)of 3706.7±552.0μg h^(−1)cm^(−2)at a current density of 100 mA cm−2,2.5 times of that in the H cell.The in situ FT-IR and Raman spectroscopic studies combined with theoretical calculations indicate that the Mn-(O-C_(2))_(4)sites not only effectively inhibit the competitive hydrogen evolution reaction,but also greatly promote the adsorption and activation of nitrate(NO_(3)^(−)),thus boosting both the FE and selectivity of NH_(3)over Mn-(O-C_(2))_(4)sites.

Identification of a locus associated with genic male sterility in maize via EMS mutagenesis and bulked-segregant RNA-seq

Genic male sterility(GMS) is one of the most important resources for exploiting heterosis in crop breeding, so that identifying genomic loci regulating GMS is desirable. However, many regulatory genes controlling GMS have not yet been characterized in maize, owing partly to a lack of genetic materials. We generated a recessive male-sterile maize mutant in the Jing 724 genetic background via ethyl methanesulfonate treatment, and found the male sterility to be due to a single gene mutation. Bulk-segregant RNA sequencing of three replicates indicated that one genomic region located at the end of chromosome 4 was associated with the observed mutant phenotype. Among genes with nonsynonymous mutations,Zm00001 d053895(bHLH51) showed abolished expression in the sterile bulks and was annotated as a bHLH transcription factor orthologous to Arabidopsis AMS, suggesting an association with the male sterility of the mutant. Kompetitive Allele-Specific PCR assays further validated the exclusive correlation of male sterility with the single C-to-T mutation in the fifth exon. The new maize mutant and the potential SNP locus provide novel genetic material for investigating the molecular mechanism underlying tapetal development and may facilitate the improvement of hybrid production systems.

Encapsulated Ni-Co alloy nanoparticles as efficient catalyst for hydrodeoxygenation of biomass derivatives in water

Catalytic hydrodeoxygenation(HDO)is one of the most promising strategies to transform oxygen-rich biomass derivatives into high value-added chemicals and fuels,but highly challenging due to the lack of highly efficient nonprecious metal catalysts.Herein,we report for the first time of a facile synthetic approach to controllably fabricate well-defined Ni-Co alloy NPs confined on the tip of N-CNTs as HDO catalyst.The resultant Ni-Co alloy catalyst possesses outstanding HDO performance towards biomass-derived vanillin into 2-methoxy-4-methylphenol in water with 100%conversion efficiency and selectivity under mild reaction conditions,surpassing the reported high performance nonprecious HDO catalysts.Impressively,our experimental results also unveil that the Ni-Co alloy catalyst can be generically applied to catalyze HDO of vanillin derivatives and other aromatic aldehydes in water with 100%conversion efficiency and over 90%selectivity.Importantly,our DFT calculations and experimental results confirm that the achieved outstanding HDO catalytic performance is due to the greatly promoted selective adsorption and activation of C=O,and desorption of the activated hydrogen species by the synergism of the alloyed Ni-Co NPs.The findings of this work affords a new strategy to design and develop efficient transition metal-based catalysts for HDO reactions in water.

Post-treatment by an ionic tetrabutylammonium hexafluorophosphate for improved efficiency and stability of perovskite solar cells

Interface engineering is an effective way to improve efficiency and long-term stability of perovskite solar cells(PSCs).Herein,an ionic compound tetrabutylammonium hexafluorophosphate(TP6)is adopted to passivate surface defects of the perovskite film.It is found that TP6 effectively reduced the surface defects,especially at the grain boundaries where the defects are abundant.Meanwhile,the exposed long alkyl chains and fluorine atoms in the TP6 enhanced the moisture stability of the perovskite film due to its strong hydrophobicity.In addition,the driving force of charge carrier separation and transport is increased by enlarged built-in potential.Consequently,the power conversion efficiency(PCE)of PSCs is significantly improved from 20.59% to 22.41%by increased open-circuit voltage(V_(oc))and fill factor(FF).The unencapsulated device with TP6 treatment exhibits better stability than the control device,and the PCE retains-80%of its initial PCE after 30 days under 15%-25%relative humidity in storage,while the PCE of the control device declines by more than 50%.

High-quality perovskite MAPbI_3 single crystals for broad-spectrum and rapid response integrate photodetector

Organic–inorganic single-crystalline perovskites have attracted significant attentions due to their exceptional progress in intrinsic properties＇ investigation and applications in photovoltaics and optoelectronics. In this study, the large perovskite CH3NH3PbI3 single crystal with the largest length of 80 mm was prepared through the method of inverse-temperature crystallization. Meanwhile, the mass production of integrate photodetectors have been fabricated on the single-crystalline wafer and the photoresponse performances were investigated. The results show that the single-crystalline photodetectors have broad spectrum response to 900 nm, rapid response speed（〈40 μs） and excellent stability. These findings are of great importance for future promising perovskite single crystalline for integrated photoelectronic application.

Preliminary Study on Production Conditions and Action Mechanism of Antifuingal Protein from Strain HJX1

Antagonistic bacterium HJXI is a Bacillus subtilis strain isolated from field rhizasphere soil where banana wih was serious, with certain control efficacy on banana Fusarium wilt. The crude extract obtained from its fermentation broth after ammonium sulfate precipitation has an inhibitory effect on various pathogenic fungi. The culture conditions for this strain were optimized in this study with Fusarium oxysporum f. sp. ettbense as an indicator, and the results showed that the fermentation broth obtained from culture in LB liquid medium under 30 ℃ at 170 r/min for48 h had the strongest inhibition against F. oxysparum f. 8p. cubense. It was observed that the inhibition was mainly reflected by causing breakage and distortion of myeelia, followed by appearance of vesicles and swelling, ablation, and leakage of protoplasm. This study provides a scientific basis for the study on the action mechanism of crude protein from bacterial strain HJX1.

Heterostructure Cu_(3)P-Ni_(2)P/CP catalyst assembled membrane electrode for high-efficiency electrocatalytic nitrate to ammonia

Electrochemical nitrate reduction reaction(NO_(3)RR)is a promising means for generating the energy carrier ammonia.Herein,we report the synthesis of heterostructure copper-nickel phosphide electrocatalysts via a simple vapor-phase hydrothermal method.The resultant catalysts were evaluated for electrocatalytic nitrate reduction to ammonia(NH_(3))in three-type electrochemical reactors.In detail,the regulation mechanism of the heterogeneous Cu_(3)P-Ni_(2)P/CP-x for NO_(3)RR performance was systematically studied through the H-type cell,rotating disk electrode setup,and membrane-electrode-assemblies(MEA)electrolyzer.As a result,the Cu_(3)P-Ni_(2)P/CP-0.5 displays the practicability in an MEA system with an anion exchange membrane,affording the largest ammonia yield rate(RNH_(3))of 1.9 mmol·h^(−1)·cm^(−2),exceeding most of the electrocatalytic nitrate reduction electrocatalysts reported to date.The theoretical calculations and in-situ spectroscopy characterizations uncover that the formed heterointerface in Cu_(3)P-Ni_(2)P/CP is beneficial for promoting nitrate adsorption,activation,and conversion to ammonia through the successive hydrodeoxygenation pathway.

Spatial heterogeneity and source apportionment of soil metal(loid)s in an abandoned lead/zinc smelter

Metal smelting have brought severe metal(loid)s contamination to the soil.Spatial distribution and pollution source analysis for soil metal(loid)s in an abandoned lead/zinc smelter were studied.The results showed that soil was contaminated heavily withmetal(loid)s.The mean of lead(Pb),arsenic(As),cadmium(Cd),mercury(Hg)and antimony(Sb)content in topsoil is 9.7,8.2,5.0,2.3,and 1.2 times higher than the risk screening value for soil contamination of development land of China(GB36600-2018),respectively.Cd ismainly enriched in the 0–6mdepth of site soil while As and Pbmainly deposited in the 0–4mlayer.The spatial distribution of soil metal(loid)s is significantly correlated with the pollution source in the different functional areas of smelter.As,Hg,Sb,Pb and copper(Cu)were mainly distributed in pyrometallurgical area,while Cd,thallium(Tl)and zinc(Zn)was mainly existed in both hydrometallurgical area and raw material storage area.Soil metal(loid)s pollution sources in the abandoned smelter are mainly contributed to the anthropogenic sources,accounting for 84.5%.Specifically,Pb,Tl,As,Hg,Sb and Cumainly from atmospheric deposition(55.9%),Cd and Zn mainly from surface runoff(28.6%),While nickel(Ni)mainly comes from parent material(15.5%).The results clarified the spatial distribution and their sources in different functional areas of the smelter,providing a new thought for the risk prevention and control of metal(loid)s in polluted site soil.

Tough,rapid self-recovery and responsive organogel-based ionotronic for intelligent continuous passive motion system

Continuous passive motion(CPM)is an adjunct therapy to the standard postoperative rehabilitation regimen of joint injuries.The capability of real-time monitoring actual bending angle of knee joints is highly desired for treatment strategies of personalized postoperative rehabilitation and telemedicine.Here we report an intelligent CPM system for personalized rehabilitation and telemedicine based on the flexible and versatile ionotronic that possesses impressive mechanical properties(2.56 MPa tensile strength;11.63 MJ m^(−3)toughness),fast self-recovery ability(60 s)and broaden environmental tolerance(−60–45°C).Especially,the ionotronic responds fast and shows stability for cyclic strain sensing,ensuring the detection of actual joint bending angle with high sensitivity and reliability.The intelligent CPM system assembled with this ionotronic and a wireless transmitter was constructed,opening up a horizon for developing digital intelligent medical that can remotely monitor the movement of hospitalized/at-home patients who use CPM for personalized postoperative rehabilitation.

Spatial Distribution of Meteorological Factors During the Key Growth Periods of Apple Cultivation in Longdong Region of Gansu Province

With the ongoing development of the apple industry in the Longdong region of Gansu,this sector has emerged as a key driver for the government s initiatives aimed at increasing stable income for local residents and promoting rural revitalization.The Longdong region boasts a favorable geographical location and a suitable climatic environment,making it an ideal area for apple cultivation.This paper analyzes meteorological data from the national meteorological observatory in Longdong over the past forty years,focusing on average temperature,precipitation,sunshine duration,and relative humidity during three critical growth periods of apples.The research reveals significant differences in the distribution of meteorological conditions across these key growth stages.Notably,the average temperature is higher in the central and northern parts of the region,while lower temperatures are observed in the southwestern areas.The average daily maximum temperature tends to be higher in the northwest and lower in the central and southwestern regions.Conversely,the average daily minimum temperature demonstrates a distinct pattern,being higher in the south and lower in the north.Additionally,precipitation is more abundant in the southeast and less so in the northwest.Sunshine hours are greater in the northern and central regions,while the southwestern and northeastern areas receive fewer hours of sunlight.Finally,relative humidity is higher in the south and lower in the north.

The HuangZaoSi Maize Genome Provides Insights into Genomic Variation and Improvement History of Maize

Maize is a globally important crop that was a classic model plant for genetic studies. Here, we report a 2.2 Gb draft genome sequence of an elite maize line, HuangZaoSi (HZS). Hybrids bred from HZS-improved lines (HILs) are planted in more than 60% of maize fields in China. Proteome clustering of six completed sequeneed maize genomes show that 638 proteins fall into 264 HZS-specific gene families with the majority of contributions from tandem duplication events. Resequencing and comparative analysis of 40 HZSrelated lines reveals the breeding history of HILs. More than 60% of identified selective sweeps were clustered in identity.by.descent conserved regions, and yield-related genes/QTLs were enriched in HZS characteristic selected regions. Furthermore, we dem on strated that HZS-specific family genes were not uniformly distributed in the genome but enriched in improvement/function.related genomic regions. This study provides an important and novel resource for maize genome research and expands our knowledge on the breadth of genomic variation and improvement history of maize.

Fe/Fe2O3 nanoparticles anchored on Fe-N-doped carbon nanosheets as bifunctional oxygen electrocatalysts for rechargeable zinc-air batteries

Electrocatalysts with high catalytic activity and stability play a key role in promising renewable energy technologies, such as fuel cells and metal-air batteries. Here, we report the synthesis of Fe/Fe203 nanoparticles anchored on Fe-N-doped carbon nanosheets （Fe/Fe2Og@Fe-N-C） using shrimp shell-derived N-doped carbon nanodots as carbon and nitrogen sources in the presence of FeCI3 by a simple pyrolysis approach. Fe/Fe203@Fe-N-C obtained at a pyrolysis temperature of 1,000 ℃ （Fe/Fe2OB@Fe-N-C-1000） possessed a mesoporous structure and high surface area of 747.3 m2-g-1. As an electrocatalyst, Fe/Fe203@Fe-N-C-1000 exhibited bifunctional electrocatalytic activities toward the oxygen reduction reaction （ORR） and oxygen evolution reaction （OER） in alkaline media, com- parable to that of commercial Pt/C for ORR and RuO2 for OER, respectively. The Zn-air battery test demonstrated that Fe/Fe2OB@Fe-N-C-1000 had a superior rechargeable performance and cycling stability as an air cathode material with an open drcuit voltage of 1.47 V （vs. Ag/AgCl） and a power density of 193 mW.cm-2 at a current density of 220 mA-cm-2. These performances were better than other commercial catalysts with an open circuit voltage of 1.36 V and a power density of 173 mW-cm^-2 at a current density of 220 mA.cm-2 （a mixture of commercial Pt/C and RuO2 with a mass ratio of 1：1 was used for the rechargeable Zn-air battery measurements）. This work will be helpful to design and develop low-cost and abundant bifunctional oxygen electrocatalysts for future metal-air batteries.

Meaningful comparison of photocatalytic properties of {001} and {101} faceted anatase TiO2 nanocrystals

The facet-dependent photocatalytic performance of TiO_2 nanocrystals has been extensively investigated due to their promising applications in renewable energy and environmental fields. However, the intrinsic distinction in the photocatalytic oxidation activities between the {001}and {101} facets of anatase TiO_2 nanocrystals is still unclear and under debate. In this work, a simple photoelectrochemical method was employed to meaningfully quantify the intrinsic photocatalytic activities of {001} and{101} faceted TiO_2 nanocrystal photoanodes. The effective surface areas of photoanodes with different facets were measured based on the monolayer adsorption of phthalic acid on TiO_2 photoanode surface by an ex situ photoelectrochemical method, which were used to normalize the photocurrents obtained from different faceted photoanodes for meaningful comparison of their photocatalytic activities. The results demonstrated that the {001} facets of anatase TiO_2 nanocrystals exhibited much better photocatalytic activity than that of {101} facets of anatase TiO_2 nanocrystals toward photocatalytic oxidation of water and organic compounds with different functional groups(e.g.,–OH, –CHO, –COOH). Furthermore, the instantaneous kinetic constants of photocatalytic oxidation of pre-adsorbates on {001} faceted anatase TiO_2 photoanode are obviously greater than those obtained at {101} faceted anatase TiO_2 photoanode, further verifying the higher photocatalytic activity of {001} facets of anatase TiO_2.This work provided a facile photoelectrochemical method to quantitatively determine the photocatalytic oxidation activity of specific exposed crystal facets of a photocatalyst, which would be helpful to uncover and meaningfully compare the intrinsic photocatalytic activities of different exposed crystal facets of a photocatalyst.

Integration of Fe_(2)O_(3)-based photoanode and atomically dispersed cobalt cathode for efficient photoelectrochemical NH_(3) synthesis

Realizing nitrogen reduction reaction(NRR) to synthesis NH_(3) under mild conditions has gained extensive attention as a promising alternative way to the energy-and emission-intensive Haber-Bosch process.Among varieties of potential strategies,photoelectrochemical(PEC) NRR exhibits many advantages including utilization of solar energy,water(H_(2)O) as the hydrogen source and ambient operation conditions.Herein,we have designed a solar-driven PEC-NRR system integrating high-efficiency Fe_(2)O_(3)-based photoanode and atomically dispersed cobalt(Co) cathode for ambient NH3 synthesis.Using such solar-driven PEC-NRR system,high-efficiency Fe_(2)O_(3)-based photoanode is responsible for H_(2)O/OH oxidatio n,and meanwhile the generated photoelectrons transfer to the single-atom Co cathode for the N_(2) reduction to NH_(3).As a result,this system can afford an NH_(3) yield rate of 1021.5 μg mg_(co)^(-1) h^(-1) and a faradic efficiency of 11.9% at an applied potential bias of 1.2 V(versus reversible hydrogen electrode) on photoanode in 0.2 mol/L NaOH electrolyte under simulated sunlight irradiation.

Growth and in situ transformation of TiO2 and HTiOF3 crystals on chitosan-polyvinyl alcohol co-polymer substrates under vapor phase hydrothermal conditions

A chitosan-polyvinyl alcohol （CS/PVA） co-polymer substrate possessing a large number of amino and hydroxyl groups is used as a substrate to induce the direct growth and in situ sequential transformation of fitanate crystals under HF vapor phase hydrothermal conditions. The process involves four distinct formation/ transformation stages. HTiOF3 crystals with well-defined hexagonal shapes are formed during stage I, and are subsequently transformed into {001} faceted anatase TiO2 crystal nanosheets during stage II. Interestingly, the formed anatase TiO2 crystals are further transformed into cross-shaped and hollow square- shaped HTiOF3 crystals during stages III and IV, respectively. Although TiO2 crystal phases and facet transformations under hydrothermal conditions have been previously reported, in situ crystal transformations between different titanate compounds have not been widely reported. Such crystal formation/ transformations are likely due to the presence of large numbers of amino groups in the CS/PVA substrate. When celluloses possessing only hydroxyl groups are used as a substrate, the direct formation of {001} faceted TiO2 nanocrystal sheets is observed （rather than any sequential crystal transformations）. This substrate organic functional group-induced crystal formation/transformation approach could be applicable to other material systems.

Interfacial engineering of metallic rhodium by thiol modification approach for ambient electrosynthesis of ammonia

Here we report a vapor-phase reaction approach to fabricate rhodium(I)-dodecanethiol complex coated on carbon fiber cloth(Rh(I)-SC_(12)H_(25)/CFC),followed by low-temperature pyrolysis to achieve dodecanethiol modified Rh(Rh@SC_(12)H_(2)5/CFC)for electrocatalytic nitrogen reduction reaction(NRR).The results demonstrate that after pyrolysis for 0.5 h at 150℃,the obtained Rh@SC_(12)H_(2)5/CFC-0.5 exhibits excellent NRR activity with an NH3 yield rate of 121.2±6.6μg∙h^(−1)∙cm^(−2)(or 137.7±7.5μg∙h^(−1)∙mgRh^(−1))and a faradaic efficiency(FE)of 51.6%±3.8%at−0.2 V(vs.RHE)in 0.1 M Na_(2)SO_(4).The theoretical calculations unveil that the adsorption of dodecanethiol on the hollow sites of Rh(111)plane is thermodynamically favorable,effectively regulating the electronic structure and surface wettability of metallic Rh.Importantly,the dodecanethiol modification on Rh(111)obviously decreases the surface H*coverage,thus inhibiting the competitive hydrogen evolution reaction and concurrently reducing the electrocatalytic NRR energy barrier.

A wrinkle to sub-100 nm yolk/shell Fe3O4@SiO2 nanoparticles

Yolk/shell nanoparticles （NPs）, which integrate functional cores （likes Fe3O4） and an inert SiO2 shell, are very important for applications in fields such as biomedicine and catalysis. An acidic medium is an excellent etchant to achieve hollow SiO2 but harmful to most functional cores. Reported here is a method for preparing sub-100 nm yolk/shell Fe3O4@SiO2 NPs by a mild acidic etching strategy. Our results demonstrate that establishment of a dissolution-diffusion equilibrium of silica is essential for achieving yolk/shell Fe3O4@SiO2 NPs. A uniform increase in the silica compactness from the inside to the outside and an appropriate pH value of the etchant are the main factors controlling the thickness and cavity of the SiO2 shell. Under our ＂standard etching code＂, the acid-sensitive Fe3O4 core can be perfectly preserved and the SiO2 shell can be selectively etched away. The mechanism of etching was investigated. regulation of SiO2 etching and acidic