Hollow Ni Mo-based nitride heterojunction with super-hydrophilic/aerophobic surface for efficient urea-assisted hydrogen production

Hydrogen evolution reaction(HER)and urea oxidation reaction(UOR)are key reactions of the watercycling associated catalytic process/device.The design of catalysts with a super-hydrophilic/aerophobic structure and optimized electron distribution holds great promise.Here,we have designed a threedimensional(3D)hollow Ni/NiMoN hierarchical structure with arrayed-sheet surface based on a onepot hydrothermal route for efficient urea-assisted HER based on a simple hydrothermal process.The Ni/NiMoN catalyst exhibits super-hydrophilic/aerophobic properties with a small droplet contact angle of 6.07°and an underwater bubble contact angle of 155.7°,thus facilitating an escape of bubbles from the electrodes.Density functional theory calculations and X-ray photoelectron spectroscopy results indicate the optimized electronic structure at the interface of Ni and NiMoN,which can promote the adsorption/desorption of reactants and intermediates.The virtues combining with a large specific surface area endow Ni/NiMoN with efficient catalytic activity of low potentials of 25 mV for HER and 1.33 V for UOR at10 mA cm^(-2).The coupled HER and UOR system demonstrates a low cell voltage of 1.42 V at 10 mA cm^(-2),which is approximately 209 mV lower than water electrolysis.

Recent research progress in the mechanism and suppression of fusion welding-induced liquation cracking of nickel based superalloys

Nickel-based superalloys are extensively used in the crucial hot-section components of industrial gas turbines,aeronautics,and astronautics because of their excellent mechanical properties and corrosion resistance at high temperatures.Fusion welding serves as an effective means for joining and repairing these alloys;however,fusion welding-induced liquation cracking has been a challenging issue.This paper comprehensively reviewed recent liquation cracking,discussing the formation mechanisms,cracking criteria,and remedies.In recent investigations,regulating material composition,changing the preweld heat treatment of the base metal,optimizing the welding process parameters,and applying auxiliary control methods are effective strategies for mitigating cracks.To promote the application of nickel-based superalloys,further research on the combination impact of multiple elements on cracking prevention and specific quantitative criteria for liquation cracking is necessary.

Analysis of the Effect and Influencing Factors of Rural Domestic Sewage Treatment Based on A^(2)O-MBBR Integrated Process

[Objectives] This study was conducted to solve the prominent problems in the treatment of domestic sewage in southern rural areas of China. [Methods] An integrated process treatment mode of anaerobic/anoxic/aerobic moving bed biofilm reactor (A 2O-MBBR) was proposed to analyze and study its operating effect and influencing factors. [Results] The A^(2)O-MBBR mode had good COD removal efficiency and nitrogen and phosphorus removal performance, and the water quality index of the effluent met the Class A standard of GB181918-2002. This mode is suitable for treating rural domestic sewage, and has high treatment effects in different operating periods. In spring, the average removal rates of COD, NH_(4)^(+)-N, TN, TP and SS reached (83.53 ± 2.15)%, (89.44 ± 4.97)%, (67.36±18.53)%, (88.22±11.21)% and (91.73±2.25)%, respectively;In the autumn period, the average removal rates of COD, NH_(4)^(+)-N, TN, TP and SS were (83.49±2.64)%, (89.26±9.19)%, (66.05±17.00)%, (87.48±9.68)%, and (91.13±2.35)%. [Conclusions] This study provides theoretical reference and technical support for the popularization and application of A^(2)O-MBBR integrated process.

Porous S-doped carbon nitride foam with accelerated charge dynamics for synchronous photocatalytic hydrogen production and highly selective oxidation of amines

Photocatalytic hydrogen evolution coupled with organic oxidation holds great promise for converting solar energy into high-valueadded chemicals,but it is hampered by sluggish charge dynamics and limited redox potential.Herein,a porous S-doped carbon nitride(S-C_(3)N_(4−y))foam assembled from ultrathin nanosheets with rich nitrogen vacancies was synthesized using a molecular selfassembly strategy.The S dopants and N vacancies synergistically adjusted the band structure,facilitating light absorption and enhancing the oxidation ability.Moreover,the ultrathin nanosheets and porous structure provided more exposed active sites and facilitated mass and charge transfer.Consequently,S-C_(3)N_(4−y) foam exhibited enhanced photocatalytic activities for synchronous hydrogen evolution(4960μmol/(h·g))and benzylamine oxidation to N-benzylidenebenzylamine(4885μmol/(h·g))with high selectivity of>99%,which were approximately 17.6 and 72.9 times higher than those of bulk CN,respectively.The photocatalytic coupling pairing reaction promotes the water splitting by consuming H2O2,thereby improving the hydrogen evolution efficiency and achieving the production of high value-added imines.This study provides an effective route for regulating the morphology and band structure of carbon nitride for synthesizing highly valuable chemicals.

Synergistic Ru/RuO_(2) heterojunctions stabilized by carbon coating as efficient and stable bifunctional electrocatalysts for acidic overall water splitting

The development of highly active and stable acidic water oxidation electrocatalysts is of great significant for promoting the industrial application of proton exchange membrane electrolyzers.Ru-based catalysts have broad application prospects in acidic water oxidation,but their limitations in stability and activity hinder their further application.Herein,a nitrogen-doped carbon(NC)coated porous Ru/RuO_(2) heterojunctional hollow sphere(Ru/RuO_(2)/NC)is designed as high-active and stable bifunctional electrocatalyst for acidic oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).In synthesis,the key is to use mesoporous polydopamine spheres as a template for forming hollow spheres,a source of NC coating and a reducing agent for forming Ru/RuO_(2) heterojunction.The Ru/RuO_(2) heterojunction adjusts the electronic structure of Ru active sites,optimizing the adsorption of intermediate species.Furthermore,the NC coating and the interaction between NC and Ru/RuO_(2) effectively prevent Ru from over-oxidation and dissolution.The porous hollow structure provides more exposed active sites and promotes mass transfer.Impressively,Ru/RuO_(2)/NC exhibits outstanding OER and HER performance with low overpotentials of 211 and 32 mV at 10 mA·cm^(−2),respectively,and shows excellent stability.The acid water splitting electrolyzer,based on the bifunctional Ru/RuO_(2)/NC,requires low cell voltages of 1.46 and 1.76 V at 10 and 100 mA·cm^(−2),respectively,with good stability for over 100 h operation,surpassing Pt/C||RuO_(2) and most of the reported catalysts.

The spatiotemporal analysis of SARS-CoV-2 transmission in China since the termination of the dynamic zero-COVID policy

China's dynamic zero-COVID policy has effectively curbed the spread of SARS-CoV-2,while inadvertently creating immunity gaps within its population.Subsequent surges in COVID-19 cases linked to various SARS-CoV-2 lineages post-policy termination necessitate a thorough investigation into the epidemiological landscape.This study addresses this issue by analyzing a comprehensive dataset of 39,456 high-quality genomes collected nationwide over an 11-month period since policy termination.Through lineage assignment,phylogenetic analysis,pandemic pattern comparison,phylodynamic reconstruction,and recombination detection,we found that China's postepidemic period could be divided into three stages,along with dynamic changes in dominant lineages.Geographical clustering of similar lineages implies the importance of cross-border cooperation among neighboring regions.Compared to the USA,UK,and Japan,China exhibits unique trajectories of lineage epidemics,characterized by initial lagging followed by subsequent advancement,indicating the potential influence of diverse prevention and control policies on lineage epidemic patterns.Hong Kong,Shanghai,and Hubei emerge as pivotal nodes in the nationwide spread,marking a shift in the transmission center from east to central regions of China.Although China hasn't experienced significant variant emergence,the detection and validation of the novel recombination event,XCN lineage,underscore the ongoing virus evolution.Overall,this study systematically analyzes the spatiotemporal transmission of SARS-CoV-2 virus in China since the termination of the dynamic zeroCOVID policy,offering valuable insights for regional surveillance and evidence-based public health policymaking.

Transmission restriction and genomic evolution co-shape the genetic diversity patterns of influenza A virus

Influenza A virus(IAV)shows an extensive host range and rapid genomic variations,leading to continuous emergence of novel viruses with significant antigenic variations and the potential for cross-species transmission.This causes global pandemics and seasonal flu outbreaks,posing sustained threats worldwide.Thus,studying all IAVs'evolutionary patterns and underlying mechanisms is crucial for effective prevention and control.We developed FluTyping to identify IAV genotypes,to explore overall genetic diversity patterns and their restriction factors.FluTyping groups isolates based on genetic distance and phylogenetic relationships using whole genomes,enabling identification of each isolate's genotype.Three distinct genetic diversity patterns were observed:one genotype domination pattern comprising only H1N1 and H3N2 seasonal influenza subtypes,multi-genotypes cocirculation pattern including majority avian influenza subtypes and swine influenza H1N2,and hybrid-circulation pattern involving H7N9 and three H5 subtypes of influenza viruses.Furthermore,the IAVs in multi-genotypes cocirculation pattern showed region-specific dominant genotypes,implying the restriction of virus transmission is a key factor contributing to distinct genetic diversity patterns,and the genomic evolution underlying different patterns was more influenced by host-specific factors.In summary,a comprehensive picture of the evolutionary patterns of overall IAVs is provided by the FluTyping's identified genotypes,offering important theoretical foundations for future prevention and control of these viruses.

Arbuscular mycorrhizal fungi-mediated resistance to salt spray in Cinnamomum camphora seedlings enhanced by leaf functional traits

Salt spray is a natural disturbance in coastal region.Arbuscular mycorrhizal fungi(AMF)are recognized as bio-ameliorators of soil salinity in plants.However,the mechanism through which AMF protects Cinnamomum camphora against aerial salinity remains unclear.To address this knowledge gap,plants were subjected to four fungal regimes,namely sterilized fungal inoculum,Glomus tortuosum,Funneliformis mosseae,or a combination of these two fungi,and exposed to three sprayed-salt regimes(0,7,or 14 mg NaCl cm−2 d−1)in a greenhouse.Salt spray significantly decreased photosynthetic capabilities,total dry weight,and salinity tolerance of non-mycorrhizal plants.Mycorrhizal inoculation,particularly a combination of G.tortuosum and F.mosseae,evidently mitigated the detrimental effects induced by salt spray.Meanwhile,mycorrhiza-mediated protection depended on the intensity of sprayed salt and the identity of fungal taxa.Furthermore,the enhanced resistance of mycorrhizal C.camphora seedlings to aerial salinity was mainly owing to increased leaf thickness and photosynthetic capabilities.These findings imply that inoculation with combined fungi could be an optimal strategy for cultivating C.camphora plants in coastal regions.The results gained hold the potential to offer both theoretical and practical guidance for the managers of coastal ecosystems in soil restoration and conservation.

Few-layered MoS_(2)anchored on 2D porous C_(3)N_(4)nanosheets for Ptfree photocatalytic hydrogen evolution

The Pt-free photocatalytic hydrogen evolution(PHE)has been the focus in the photocatalytic field.The catalytic system with the large accessible surface and good mass-transfer ability,as well as the intimate combination of co-catalyst with semiconductor is promising for the promotion of the application.Here,we have reported the design of the two-dimensional(2D)porous C_(3)N_(4)nanosheets(PCN NS)intimately combined with few-layered MoS_(2)for the high-effective Pt-free PHE.The PCN NS were synthesized based on peeling the melamine–cyanuric acid precursor(MC precursor)by the triphenylphosphine(TP)molecular followed by the calcination,mainly due to the matched size of the(100)plane distance of the precursor(0.8 nm)and the height of TP molecular.The porous structure is favorable for the mass-transfer and the 2D structure having large accessible surface,both of which are positive to promote the photocatalytic ability.The few-layered MoS_(2)are grown on PCN to give 2D MoS_(2)/PCN composites based on anchoring phosphomolybdic acid(PMo_(12))cluster on polyetherimide(PEI)-modified PCN followed by the vulcanization.The few-layered MoS_(2)have abundant edge active sites,and its intimate combination with porous PCN NS is favorable for the faster transfer and separation of the electrons.The characterization together with the advantage of 2D porous structure can largely promote the photocatalytic ability.The MoS_(2)/PCN showed good PHE activity with the high hydrogen production activity of 4,270.8μmol·h^(−1)·g^(−1)under the simulated sunlight condition(AM1.5),which was 7.9 times of the corresponding MoS_(2)/bulk C_(3)N_(4)and 12.7 times of the 1 wt.%Pt/bulk C_(3)N_(4).The study is potentially meaningful for the synthesis of PCN-based catalytic systems.

The“mediated molecular”-assisted construction of Mo_(2)N islands dispersed on Co-based nanosheets for high-efficient electrocatalytic hydrogen evolution reaction

The rational design of the catalysts with easily-accessible surface and high intrinsic activity is desirable for electrocatalytic hydrogen evolution reaction(HER).Here,we reported the construction of two-dimensional(2D)Co-Mo nitrides based heterojunctional catalyst for efficient HER based on a“mediated molecular”assisted route.The 2D Co(OH)_(2)sheet reacted partially with the“mediated molecular”(2-methylimidazole(2-MIM))to form zeolitic imidazolate framework(ZIF)-67 at surface,giving ZIF-67/Co(OH)_(2)sheets.The ZIF-67 combines with[PMo_(12)O_(40)]^(3−)cluster(PMo_(12))due to the interaction of mediated molecular with PMo_(12),producing 2D Mo-Co-2MIM/Co(OH)_(2)bimetallic precursor.After controlled nitriding,the Mo_(2)N islands dispersed on 2D porous Co-based sheets were formed.A series of characterizations and density functional theory(DFT)calculation indicated the formation of a close contact interface,which promotes the electron transfer between Mo and Co components,enhances the electron migration/redistribution and redistribution and down-shift of d-band center and thus gives a high intrinsic activity.The 2D characteristics make the catalyst more accessible contact sites,which is favourable to promot the HER.The tests showed that the optimized catalyst exhibits an onset potential of 0 mV and an overpotential of 10 mA·cm^(−2)at 35.0 mV,which is quite close to that of Pt/C catalyst.It also exhibits an activity superior to Pt/C at high current density(>100 mA·cm^(−2)).A good stability of the catalyst was achieved with no significant decay for 100 h of continuous operation.The electrolytic cell composed of optimized catalyst and P-NiFe-layered double hydroxide(LDH)can be driven by low voltage(only 1.47 V)to reach a current density of 10 mA·cm^(−2).

Recent progress in synergistic electrocatalysis for generation of valuable products based on water cycle

Given the grim situation of global warming and energy crisis,replacing traditional energy conversions based on carbon cycle with water cycle is a sustainable development trend.The synergistic electrocatalysis for value-added chemical production through oxygen species(O_(ads):OH^(*),O^(*),and OOH^(*))and the active hydrogen species(H_(ads))derived from water splitting powered by“green”electricity from renewable energy resource(wind,solar,etc.)is a promising manner,because of its reduced energy consumption and emission and high Faradaic efficiency.The study and summarization of catalytic mechanism of synergistic electrocatalysis are particularly significant,but are rarely involved.In this review,recent progress of various synergistic electrocatalysis systems for generating valuable products based on water cycle is systematically summarized.Importantly,the catalytic mechanism of synergistic electrocatalysis and the positive effect of O_(ads) and H_(ads) species produced by water splitting during the synergistic electrocatalytsis are detailedly elucidated.Furthermore,the regulation of water-derived O_(ads) and H_(ads) species for achieving efficient matchability of synergistic electrocatalysis is emphatically discussed.Finally,we propose the limitations and future goals of this synergistic system based on water cycle.This review is guidance for design of synergistic electrocatalysis architectures for producing valuable substances based on water cycle.

Tuning electronic structure of Ni_(3)S_(2) with tungsten doping for high-performance electrooxidation of 5-hydroxymethylfurfural

Electrooxidation of the biomass derivative 5-hydroxymethylfurfural (HMF) is a highly promising approach for attaining versatile value-added chemicals (e.g.,2,5-furandicarboxylic acid,FDCA).Ni-based sulfides are promising electrocatalysts for HMF electrooxidation reaction (HMFOR).However,the HMFOR activity of Ni-based catalysts is far from satisfactory due to the unfavorable adsorption of HMF and OH^(*).Herein,we propose controlled W doping to effectively modify the electronic configuration of nanostructured Ni_(3)S_(2) to manipulate adsorption of HMF and OH^(*),for efficiently converting HMF into FDCA.Experimental and theoretical calculations indicate the incorporation of high-valence W results in the upshift of d-band center of Ni_(3)S_(2),which facilitates the adsorption and dissociation of water to produce more OH^(*).Meanwhile,the high-valence W has strong electron-withdrawing ability and attracts electrons from Ni,leading to the elevated Ni valence,which is beneficial to optimizing the adsorption energy of HMF.Both concurrently contribute to the superb HMFOR performance.As a result,W_(20)-Ni_(3)S_(2)@NF with optimal W dopant exhibits a low driving potential (1.34 V vs.RHE at 10 mA cm^(-2)),accompanying with the 100% HMF conversion,99.2%FDCA selectivity,and 97.3%Faraday efficiency.This work provides a design principle for HMFOR electrocatalysts by modulating the adsorption behaviors of HMF and OH^(*)via rational electronic structure engineering.

Integrated interactome and transcriptome analysis reveals key host factors critical for SARS-CoV-2 infection

The coronavirus disease 2019(COVID-19)pandemic,caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),has seriously threatened global public health and caused huge economic losses.Omics studies of SARS-CoV-2 can help understand the interaction between the virus and host,thereby providing a new perspective in guiding the intervention and treatment of the SARS-CoV-2 infection.Since large amount of SARS-CoV-2 omics data have been accumulated in public databases,this study aimed to identify key host factors involved in SARSCoV-2 infection through systematic integration of transcriptome and interactome data.By manually curating published studies,we obtained a comprehensive SARS-CoV-2-human protein-protein interactions(PPIs)network,comprising 3591 human proteins interacting with 31 SARS-CoV-2 viral proteins.Using the RobustRankAggregation method,we identified 123 multiple cell line common genes(CLCGs),of which 115 up-regulated CLCGs showed host enhanced innate immunity and chemotactic response signatures.Combined with network analysis,co-expression and functional enrichment analysis,we discovered four key host factors involved in SARS-CoV-2 infection:IFITM1,SERPINE1,DDX60,and TNFAIP2.Furthermore,SERPINE1 was found to facilitate SARSCoV-2 replication,and can alleviate the endoplasmic reticulum(ER)stress induced by ORF8 protein through interaction with ORF8.Our findings highlight the importance of systematic integration analysis in understanding SARS-CoV-2-human interactions and provide valuable insights for future research on potential therapeutic targets against SARS-CoV-2 infection.

Synchronous regulation of morphology and electronic structure of FeNi-P nanosheet arrays by Zn implantation for robust overall water splitting

FeNi-based phosphides are one of the most hopeful electrocatalysts,whereas the significant challenge is to achieve prominent bifunctional catalytic activity with low voltage for water splitting.The morphology and electronic structure of FeNi-based phosphides can intensively dominate effective catalysis,therefore their simultaneous regulating is extremely meaningful.Herein,a robust bifunctional catalyst of Zn-implanted FeNi-P nanosheet arrays(Zn-FeNi-P)vertically well-aligned on Ni foam is successfully fabricated by Zn implanting strategy.The Zn fulfills the role of electronic donor due to its low electronegativity to enhance the electronic density of FeNi-P for optimized water dissociation kinetics.Meanwhile,the implantation of Zn into FeNi-P can effectively regulate morphology of the catalyst from thick and irregular nanosheets to ultrathin lamellar structure,which generates enriched catalytic active sites,leading to accelerating electron/mass transport ability.Accordingly,the designed Zn-FeNi-P catalyst manifests remarkable hydrogen evolution reaction(HER)activity with low overpotentials of 55 and 225 mV at 10 and 200 mA·cm^(−2),which is superior to the FeNi-P(82 mV@10 mA·cm^(−2)and 301 mV@200 mA·cm^(−2)),and even out-performing the Pt/C catalyst at a high current density>200 mA·cm^(−2).Moreover,the oxygen evolution reaction(OER)activity of Zn-FeNi-P also has dramatically improved(207 mV@10 mA·cm^(−2))comparable to FeNi-P(221 mV@10 mA·cm^(−2))and RuO_(2)(239 mV@10 mA·cm^(−2)).Noticeably,an electrolyzer based on Zn-FeNi-P electrodes requires a low cell voltage of 1.47 V to achieve 10 mA·cm^(−2),far beyond the catalytic activities of FeNi-P||FeNi-P(1.51 V@10 mA·cm^(−2))and the benchmark RuO_(2)||Pt/C couples(1.56 V@10 mA·cm^(−2)).This Zn-implanting strategy paves a new perspective for the development of admirable bifunctional catalysts.

Mapping Chinese Medical Entities to the Unified Medical Language System

Background.Chinese medical entities have not been organized comprehensively due to the lack of welldeveloped terminology systems,which poses a challenge to processing Chinese medical texts for finegrained medical knowledge representation.To unify Chinese medical terminologies,mapping Chinese medical entities to their English counterparts in the Unified Medical Language System(UMLS)is an efficient solution.However,their mappings have not been investigated sufficiently in former research.In this study,we explore strategies for mapping Chinese medical entities to the UMLS and systematically evaluate the mapping performance.Methods.First,Chinese medical entities are translated to English using multiple web-based translation engines.Then,3 mapping strategies are investigated:(a)stringbased,(b)semantic-based,and(c)string and semantic similarity combined.In addition,cross-lingual pretrained language models are applied to map Chinese medical entities to UMLS concepts without translation.All of these strategies are evaluated on the ICD10-CN,Chinese Human Phenotype Ontology(CHPO),and RealWorld datasets.Results.The linear combination method based on the SapBERT and term frequency-inverse document frequency bag-of-words models perform the best on all evaluation datasets,with 91.85%,82.44%,and 78.43%of the top 5 accuracies on the ICD10-CN,CHPO,and RealWorld datasets,respectively.Conclusions.In our study,we explore strategies for mapping Chinese medical entities to the UMLS and identify a satisfactory linear combination method.Our investigation will facilitate Chinese medical entity normalization and inspire research that focuses on Chinese medical ontology development.

Small-sized tungsten nitride anchoring into a 3D CNT- rGO framework as a superior bifunctional catalyst for the methanol oxidation and oxygen reduction reactions

The application of direct methanol fuel cells （DMFC） is hampered by high cost, low activity, and poor CO tolerance by the Pt catalyst. Herein, we designed a fancy 3D hybrid by anchoring tungsten nitride （WN） nanoparticles （NPs）, of about 3 nm in size, into a 3D carbon nanotube-reduced graphene oxide framework （CNT-rGO） using an assembly route. After depositing Pt, the contacted and strongly coupled Pt-WN NPs were formed, resulting in electron transfer from Pt to WN. The 3D Pt-WN/CNT-rGO hybrid can be used as a bifunctional electrocatalyst for both methanol oxidation reaction （MOR） and oxygen reduction reaction （ORR）. In MOR, the catalysts showed excellent CO tolerance and a high mass activity of 702.4 mA.mgpt-1, 2.44 and 3.81 times higher than those of Pt/CNT-rGO and Pt/C（JM） catalysts, respectively. The catalyst also exhibited a more positive onset potential （1.03 V）, higher mass activity （151.3 mA.mgpt-1）, and better cyclic stability and tolerance in MOR than ORR. The catalyst mainly exhibited a 4e-transfer mechanism with a low peroxide yield. The high activity was closely related to hybrid structure. That is, the 3D framework provided a favorable path for mass-transfer, the CNT-rGO support was favorable for charge transfer, and strongly coupled Pt-WN can enhance the catalytic activity and CO-tolerance of Pt. Pt-WN/CNT-rGO represents a new 3D catalytic platform that is promising as an electrocatalyst for DMFC because it can catalyze both ORR and MOR in an acidic medium with good stability and highly efficient Pt utilization.

Surface curvature-confined strategy to ultrasmall nickel-molybdenum sulfide nanoflakes for highly efficient deep hydrodesulfurization

Size-controlled synthesis of two-dimensional(2D)catalysts with low stacking numbers and small nanoflake lengths is crucial for promoting the catalytic performance in diverse heterogeneous catalysis.Herein,we report a facile and general“surface curvature-confined synthesis”strategy to modulate the slab lengths and stacking numbers of 2D transition metal sulfides by controlling the strain induced by different surface curvature of supports.An efficient NiMo sulfide with shorter slab length(average 3.71 nm),less stacking number(1–2 layers)and more edge active sites is synthesized onto ZSM-5 zeolites with the average size of 100 nm,which shows superior kHDS value of dibenzothiophene(14.05×10^−7 mol/(g·s)),enhanced stability up to 80 h,and high direct desulfurization selectivity(>95%).This design concept is also proved to be generally applicable to modulate the slab lengths and stacking numbers of other 2D catalysts such as MoS2 and WS2 nanoflakes,which shows great potentials for developing more ultrasmall 2D catalysts with controlled sizes and excellent catalytic activities.

A dual-active Co-CoO heterojunction coupled with Ti_(3)C_(2)-MXene for highly-performance overall water splitting

Development of cost-effective and highly-efficient bifunctional hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalysts is crucial for overall water splitting in practical utilization.Herein,we proposed a novel non-noble metal bifunctional,HER/OER electrocatalyst by synergistically coupling a dual-active Co-based heterojunction(Co-CoO)with high conductive and stable two-dimensional Ti_(3)C_(2)-MXene(defined as Co-CoO/Ti^(3)CrMXene).A series of characterizations and theoretical calculations'verify that the synergistic effect of metallic Co with HER activity and Coo with OER performance leads to superb bifunctional catalytic performance,and Ti_(3)C_(2)-MXene can enhance electrical conductivity and prevent the aggregation of the Co-based catalysts,thereby improving both the activity arid stability.Co-Co0/Ti_(3)C_(2)-MXene presents low onset potential(11onse1)of 8 mV and,Tafel slope of 47 mV·dec^(-1) for HER(close to that of Pt/C)and 17onset of 196 mV and Tafel slope of 47 mV·dec^(-1) for OER(superior to:that of Ru02).Assembled as an electrolyzer,Co-CoO/Ti_(3)C_(2)-MXene shows a low voltage of 1.55 V at 10 mA·cm^(-2),high Faradaic efficiency and remarkable stability.It can be driven by a solar cell of-1.55 V for consecutive production of hydrogen and oxygen gases.

Strongly coupled Ag/TiO2 heterojunctions for effective and stable photothermal catalytic reduction of 4-nitrophenol

The development of effective catalysts for the catalytic conversion of the harmful nitrophenol （NP） into the useful aminophenol （AP） has received extensive interest. Herein, we report the easy and large-scale synthesis of strongly coupled Ag/TiO2 heterojunctions based on the coordinated action of organic components with a multi-kind metal precursor. The heterojunctions were effective and stable catalysts for the photothermal catalytic reduction of 4-NP to 4-AP. In the synthesis, critic acid, ethylene glycol AgNO3, and tetrabutyl titanate were dissolved and coordinated in water. Under heating, a precursor gel having a uniform distribution of Ag and Ti was gradually formed. Via calcination in air, the Ti precursor was transformed into TiO2, accompanied by the reduction of Ag＋ to Ag nanoparticles. The formation of Ag/TiO2 composites with intimate interface contact benefited from the uniform distribution of different components in the precursor gel. The Ag/TiO2 functioned as an effective catalyst for the reduction of 4-NP, exhibiting higher activity than the many reported Ag-based catalysts. The catalytic reaction over Ag/TiO2 had a small to with good activity and reuse performance. After 10 cycles of reuse, the conversion efficiency exhibited no obvious change. Importantly, the conversion of 4-NP was significantly enhanced under light irradiation provided by a 150-W Xe lamp （the visible light from cutoff have equal function）, but ultraviolet light did not promote the conversion. The conversion time was reduced from 620 to 270 s with light irradiation （15 ~C）. The reaction rate under light irradiation （0.014 s-1） was approximately three times higher than that in the dark at 15 ~C （0.0044 s-1） and even better than that in the dark at 25 ~C （0.01 s-l）. A series of experiments indicated that the light irradiation promoted the conversion of 4-NP because of the localized surface plasmon resonance effect of Ag, which generated hot e- and h~ particles and local heating around the particles via their absorption of the light.