Construction of hierarchical photocatalysts by growing ZnIn_(2)S_(4) nanosheets on Prussian blue analogue-derived bimetallic sulfides for solar co-production of H_(2) and organic chemicals

Exploring highly efficient bifunctional photocatalysts for simultaneous H2 evolution and organic chemical production in pure water represents a green route for sustainable solar energy storage and conversion.Herein,a facile strategy was explored for preparing a hierarchical porous heterostructure of Fe_(4)Ni_(5)S_(8)@ZnIn_(2)S_(4)(FNS@ZIS)by the in situ growth of ZIS nanosheets on Prussian blue analogue(PBA)-derived bimetallic FNS sulfides.A series of FNS@ZIS hierarchical structures were facilely prepared by adjusting the loading amount(n%)of FNS(n=19,26,and 32 for FNS@ZIS-1-3).These structures can efficiently drive the solar co-production of H_(2) and organic chemicals.The optimal co-production was achieved with FNS@ZIS-2,affording a H_(2) evolution rate of 10465μmol·g^(-1)·h^(-1),along with high selectivity for the oxidation of benzyl alcohol to benzaldehyde(>99.9%).The performance was 22 and 31 times higher than that of FNS and ZIS,respectively,and even superior to the state-of-the-art results achieved using various sacrificial agents.Further mechanistic study indicated that the unique hierarchical core/shell architecture can facilitate interfacial charge separation,afford bimetallic synergy,abundant active sites and excellent photostability.This work highlights a simple and efficient method for preparing porous multimetallic hierarchical structures for the solar co-production of organic chemicals and H_(2) fuel.

Ligand-free CsPbBr_(3) with calliandra-like nanostructure for efficient artificial photosynthesis

The low-efficiency CO_(2) uptake capacity and insufficient photogenerated exciton dissociation of current metal halide perovskite(MHP)nanocrystals with end-capping ligands extremely restrict their application in the field of artificial photosynthesis.Herein,we demonstrate that ligand-free CsPbBr_(3) with calliandralike nanostructure(LF-CPB CL)can be synthesized easily through a ligand-free seed-assisted dissolutionrecrystallization growth process,exhibiting significantly enhanced CO_(2) uptake capacity.More specifically,the abundant surface bromine(Br)vacancies in ligand-free MHP materials are demonstrated to be beneficial to photogenerated carrier separation.The electron consumption rate of LF-CPB CL for photocatalytic CO_(2) reduction increases 7 and 20 times over those of traditional ligand-capping CsPbBr_(3)nanocrystal(L-CPB NC)and bulk CsPbBr_(3),respectively.Moreover,the absence of ligand hindrance can facilitate the interfacial electronic coupling between LF-CPB CL and tetra(4-carboxyphenyl)porphyrin iron(Ⅲ)chloride(Fe-TCPP)cocatalyst,bringing forth significantly accelerated interfacial charge separation.The LF-CPB CL/Fe-TCPP exhibits a total electron consumption rate of 145.6μmol g^(-1) h^(-1) for CO_(2)photoreduction coupled with water oxidation which is over 14 times higher than that of L-CPB NC/FeTCPP.

Electrochemical urea synthesis by co-reduction of CO_(2) and nitrate with Fe^(Ⅱ)-Fe^(Ⅲ)OOH@BiVO_(4) heterostructures

Traditional urea synthesis under harsh conditions is usually associated with high energy input and has aroused severe environmental concerns.Electrocatalytic C-N coupling by converting nitrate and CO_(2) into urea under ambient conditions represents a promising alternative process.But it was still limited by the strong competition between nitrate electrochemical reduction(NO_(3)ER) and CO_(2) electrochemical reduction(CO_(2)ER).Here,Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-n heterostructures are constructed through hydrothermal synthesis and exhibited superior performance toward urea electrosynthesis with NO_(3)~-and CO_(2) as feedstocks.The optimized urea yield and Faradaic efficiency over Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-2 can reach13.8 mmol h^(-1) g^(-1) and 11.5% at-0.8 V vs.reversible hydrogen electrode,which is much higher than that of bare FeOOH(3.2 mmol h^(-1) g^(-1) and 1.3%),pristine BiVO_(4)(2.0 mmol h^(-1) g^(-1) and 5.4%),and the other Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-n(n=1,3,5) heterostructures.Systematic experiments have verified that BiVO_(4)and FeOOH are subreaction active sites towards simultaneous CO_(2)ER and NO_(3)ER,respectively,achieving co-activation of CO_(2) and NO_(3)~-on Fe^(Ⅱ)-Fe~ⅢOOH@BiVO_(4)-2.Moreover,the urea synthesis via the ^(*)CO and NO*intermediates and C-N coupling was confirmed by the in situ Fourier transform infrared spectroscopy.This work not only alleviates the CO_(2) emission and nitrate pollution but also presents an efficient catalyst for synergistic catalysis towards sustainable urea synthesis.

Self-template-oriented synthesis of lead-free perovskite Cs_(3)Bi_(2)I_(9) nanosheets for boosting photocatalysis of CO_(2) reduction over Z-scheme heterojunction Cs_(3)Bi_(2)I_(9)/CeO_(2)

Lead halide perovskite (LHP) nanocrystals have been intensely studied as photocatalysts for artificial photosynthesis in recent years.However,the toxicity of lead in LHP seriously limits their potential for widespread applications.Herein,we first present the synthesis of 2D lead-free halide perovskite (Cs_(3)Bi_(2)I_(9)) nanosheets with self-template-oriented method,in which BiOI/Bi_(2)O_(2) nanosheets were used as the template and Bi ion source simultaneously.Through facile electrostatic self-assembly strategy,a Z-scheme heterojunction composed of Cs_(3)Bi_(2)I_(9)nanosheets and CeO_(2) nanosheets (Cs_(3)Bi_(2)I_(9)/CeO_(2)-3:1) was constructed as photocatalyst for the photo-reduction of CO_(2) coupled with the oxidation of H_(2)O.Due to the matching energy levels and the close interfacial contact between Cs_(3)Bi_(2)I_(9)and CeO_(2) nanosheets,the separation efficiency of the photogenerated carriers in Cs_(3)Bi_(2)I_(9)/CeO_(2)-3:1 composite was significantly improved.Consequently,the environment-friendly halide perovskite heterojunction Cs_(3)Bi_(2)I_(9)/CeO_(2)-3:1presents impressive photocatalytic activity for the reduction of CO_(2)to CH_(4)and CO with an electron consumption yield of 877.04μmol g^(-1),which is over 7 and 15 times higher than those of pristine Cs_(3)Bi_(2)I_(9)and CeO_(2)nanosheets,exceeding the yield of other reported bismuth-based perovskite for photocatalytic CO_(2)reduction.

Sensitizing photoactive metal-organic frameworks via chromophore for significantly boosting photosynthesis

Photosensitization related to energy/electron transfer process is of great importance to natural photosynthesis.Herein,we proposed a promising strategy to improve the sensitizing ability of the typical photoactive MOFs(UiO-Ir)by engineering its metal coordination center with NBI(1,8-naphthalenebenzimidizole)chromophore.The resulting MOFs(UiO-Ir-NBI)exhibited a strong sensitizing ability for significantly boosting photosynthesis.Impressively,the catalytic yield of 2-chloroethyl ethyl sulfoxide with UiO-Ir-NBI can reach 99%,over 6 times higher than that with UiO-Ir(16.4%).Moreover,UiO-Ir-NBI exhibited an excellent catalytic stability and a broad substrate tolerance,highlighting its great application prospect.Systematic investigations revealed that the strong visible light absorption,long excited state lifetime and efficient electron-hole separation of UiO-Ir-NBI greatly contributed to harvesting visible light and facilitating interface electron/energy transfer for efficient solar energy utilization.This work provides a new horizon to boost photosythesis of MOFs by engineering their metal sensitizing centers at a molecular level.

Surface iodine and pyrenyl-graphdiyne co-modified Bi catalysts for highly efficient CO_(2) electroreduction in acidic electrolyte

CO_(2) electroreduction to formic acid/formate would contribute to alleviating the energy and climate crisis.This work reports a Bi-based catalyst derived from the in-situ electroreduction of Bi_(2)O_(2)CO_(3) modified with iodine and pyrenyl-graphdiyne(PGDY)on the surface for efficient electroreduction of CO_(2) in acidic electrolyte,with a high partial current density of 98.71 mA·cm^(-2) and high Faradaic efficiency(FE)>90%over the potential range from^(-1).2 to-1.5 V vs.reversible hydrogen electrode(RHE),as well as the long-term operational stability over 240 h without degradation in H-type cell.Experimental results and density function theory calculations show that the synergistic effect of surface iodine and PGDY is responsible for this active and extremely stable process of CO_(2) electroreduction via lowering the energy barriers for formation of*OCHO intermediate,suppressing the competitive HER by enhancing the concentration of both K+and CO_(2) at reaction interface,as well as preventing the dissolution and re-deposition of active Bi atoms on surface during catalytic reaction.This work provides new insight into designing highly active and stable electrocatalysts for CO_(2) reduction.

Photocatalytic reduction of CO_(2) with H_(2)O into C_(2)H_(6) mediated by dual metalation strategy

Artificial solar-energy-driven CO2reduction into value-added fuels under mild conditions provides a promising strategy to mitigate energy crisis and alleviate environmental issues around the world. Among diverse products of CO_(2) reduction reaction, C_(2+) compounds are more desirable in terms of their high energy density and commercial value [1].Thus far, various photocatalysts have been constructed for CO_(2) reduction.

Cobalt-based heterogeneous catalysts for photocatalytic carbon dioxide reduction

Solar light-driven CO_(2)reduction to high value-added chemicals has considered as an outstanding way to solve energy crisis and climate warming.Recently,various photocatalysts have been developed to achieve this reaction.Among them,cobaltbased heterogeneous catalysts have attracted great interest because of their promising performance,product selectivity and stability.Herein,we systematically summarize the research progress of various cobalt-based heterogeneous catalysts for the photoreduction of CO_(2),such as single-atom cobalt,and cobalt-based oxides,nitrides,sulfi des,phosphides,metal-organic frameworks and covalent-organic frameworks.Meanwhile,the advantages and structure-activity relationship of these catalysts in photocatalytic CO_(2)reduction reaction are discussed.Finally,the challenges and prospects for constructing cobaltbased heterogeneous catalysts with high effi ciency are highlighted.

Optically modulated dual-mode memristor arrays based on core-shell CsPbBr_(3)@graphdiyne nanocrystals for fully memristive neuromorphic computing hardware

Artificial synapses and neurons are crucial milestones for neuromorphic computing hardware,and memristors with resistive and threshold switching characteristics are regarded as the most promising candidates for the construction of hardware neural networks.However,most of the memristors can only operate in one mode,that is,resistive switching or threshold switching,and distinct memristors are required to construct fully memristive neuromorphic computing hardware,making it more complex for the fabrication and integration of the hardware.Herein,we propose a flexible dual-mode memristor array based on core–shell CsPbBr3@graphdiyne nanocrystals,which features a 100%transition yield,small cycle-to-cycle and device-to-device variability,excellent flexibility,and environmental stability.Based on this dual-mode memristor,homo-material-based fully memristive neuromorphic computing hardware—a power-free artificial nociceptive signal processing system and a spiking neural network—are constructed for the first time.Our dual-mode memristors greatly simplify the fabrication and integration of fully memristive neuromorphic systems.

W/Mo-polyoxometalate-derived electrocatalyst for high-efficiency nitrogen fixation

Ammonia is the feedstock chemical for most fertilizers and the alternative of renewable energy carriers.Environmentally benign electrochemical nitrogen reduction reaction (NRR) under mild conditions has been recognized as one of the most attractive strategies for N_(2) fixation.Herein,inspired by Mobased nitrogenase,W/Mo-doping electrocatalysts were developed with mixed-metal polyoxometalate H_(3)PW_6Mo_6O_(40) as the precursor for high performance electrocatalytic NRR.Trace amount of Pt was transplanted on the surface of W/Mo@rGO via in situ electroplating treatment to further improve the NRR performance.The resulting Pt-W/Mo@rGO-6 achieves excellent performance for NRR with a high NH_(3)yield of 79.2μg h^(-1)mg_(cat)^(-1) due to the multicomponent synergistic effect in the composite catalyst.The Pt-W/Mo@rGO-6 represents the first example of highly efficient NRR electraocatalyst derived from mixed-metal polyoxometalate,which exhibits outstanding stability confirmed by the constant catalytic performance over 24 h chronoamperometric test.This finding opens a new avenue to construct highly efficient NRR electrocatalyst by employing mixed metal polyoxometalate as the precursor under ambient conditions.

Lattice-matched in-situ construction of 2D/2D T-SrTiO_(3)/CsPbBr_(3) heterostructure for efficient photocatalysis of CO_(2) reduction

The elaborate regulation of heterostructure interface to accelerate the interfacial charge separation is one of practicable approaches to improve the photocatalytic CO_(2)reduction performance of halide perovskite(HP) materials. Herein, we report an in-situ growth strategy for the construction of 2D CsPbBr_(3)based heterostructure with perovskite oxide(SrTiO_(3)) nanosheet as substrate(CsPbBr_(3)/SrTiO_(3)). Lattice matching and matchable energy band structures between CsPbBr_(3)and SrTiO_(3)endow CsPbBr_(3)/SrTiO_(3)heterostructure with an efficient interfacial charge separation. Moreover, the interfacial charge transfer rate can be further accelerated by etching SrTiO_(3)with NH_(4)F to form flat surface capped with Ti-O bonds. The resultant 2D/2D T-SrTiO_(3)/CsPbBr_(3)heterostructure exhibits an impressive photocatalytic activity for CO_(2)conversion with a CO yield of 120.2 ± 4.9 μmol g^(-1)h^(-1)at the light intensity of 100 m W/cm^(2)and water as electron source, which is about 10 and 7 times higher than those of the pristine SrTiO_(3)and CsPbBr_(3)nanosheets, surpassing the reported halide perovskite-based photocatalysts under the same conditions.

Graphdiyene enables ultrafine Cu nanoparticles to selectively reduce CO_(2) to C_(2+)products

Reducing the size of heterogeneous nanocatalysts is generally conducive to improving their atomic utilization and activities in various catalytic reactions.However,this strategy has proven less effective for Cu-based electrocatalysts for the reduction of CO_(2) to multicarbon(O2+)products,owing to the overly strong binding of intermediates on small-sized(<15 nm)Cu nanoparticles(NPs).Herein,by incorporating pyreny-graphdiyne(Pyr-GDY),we successfully endowed ultrafine(〜2 nm)Cu NPs with a significantly elevated selectivity for CO_(2)-to-C_(2+)conversion.The Pyr-GDY can not only help to relax the overly strong binding between adsorbed H*and CO*intermediates on Cu NPs by tailoring the d-band center of the catalyst,but also stabilize the ultrafine Cu NPs through the high affinity between alkyne moieties and Cu NPs.The resulting Pyr-GDY-Cu composite catalyst gave a Faradic efficiency(FE)for C2+products up to 74%,significantly higher than those of support-free Cu NPs(C2+FE.〜2%),carbon nanotube-supported Cu NPs(CNT-Cu,C_(2+)FE,〜18%),graphene oxide-supported Cu NPs(GO-Cu,C_(2+)FE,〜8%),and other reported ultrafine Cu NPs.Our results demonstrate the critical influence of graphdiyne on the selectivity of Cu-catalyzed CO_(2) electroreduction,and showcase the prospect for ultrafine Cu NPs catalysts to convert CO_(2) into value-added C_(2+)products.

Synthesis of wafer-scale graphdiyne/graphene heterostructure for scalable neuromorphic computing and artificial visual systems

Graphdiyne(GDY)is emerging as a promising material for various applications owing to its unique structure and fascinating properties.However,the application of GDY in electronics and optoelectronics are still in its infancy,primarily owing to the huge challenge in the synthesis of large-area and uniform GDY film for scalable applications.Here a modified van der Waals epitaxy strategy is proposed to synthesize wafer-scale GDY film with high uniformity and controllable thickness directly on graphene(Gr)surface,providing an ideal platform to construct large-scale GDY/Gr-based optoelectronic synapse array.Essential synaptic behaviors have been realized,and the linear and symmetric conductance-update characteristics facilitate the implementation of neuromorphic computing for image recognition with high accuracy and strong fault tolerance.Logic functions including“NAND”and“NOR”are integrated into the synapse which can be executed in an optical pathway.Moreover,a visible information sensing-memory-processing system is constructed to execute real-time image acquisition,in situ image memorization and distinction tasks,avoiding the time latency and energy consumption caused by data conversion and transmission in conventional visual systems.These results highlight the potential of GDY in applications of neuromorphic computing and artificial visual systems.

Facile synthesis of C_(3)N_(4)-supported metal catalysts for efficient CO_(2) photoreduction

Facile synthesis of photocatalysts with highly dispersed metal centers is a high-priority target yet still a significant challenge.In this work,a series of Co-C_(3)N_(4) photocatalysts with different Co contents atomically dispersed on g-CaN4 have been prepared via one-step thermal treatment of cobalt-based metal-organic frameworks(MOFs)and urea in the air.Thanks to the highly dispersed and rich exposed Co sites,as well as good charge separation efficiency and abundant mesopores,the optimal 25-Co-C_(3)N_(4),in the absence of noble metal catalysts/sensitizers,exhibits excellent performance for photocatalytic C0_(2) reduction to CO under visible.light irradiation,with a high CO evolution rate of 394.4μmol·g^(-1)·h^(-1),over 80 times higher than that of pure g-C_(3)N_(4)(4.9μmol·g^(-1)·h^(-1)).In:addition,by this facile synthesis strategy,the atomically dispersed Fe and Mn anchoring on g-C_(3)N_(4)(Fe-C_(3)N_(4) and Mn-C_(3)N_(4))have been also obtained,indicating the reliability and universality of this strategy in synthesizing photocatalysts with highly dispersed metal centers.This work paves a new way to develop cost-effective photocatalysts for photocatalytic C0_(2) reduction.

Enhancing the photoelectrocatalytic performance of metal-free graphdiyne-based catalyst

As a new member of the carbon family,graphdiyne is an intrinsic semiconductor featuring a natural bandgap,which endues it potential for direct application in photoelectric devices.However,without cooperating with other active materials,conventional hexacetylene-benzene graphdiyne(HEB-GDY)shows poor performances in photocatalysis and photoelectric devices due to its non-ideal visible light absorption,low separation efficiency of the photogenerated carriers and insufficient sites for hydrogen production.Herein,we report a molecular engineering strategy for the regulation of GDY-based carbon materials,by incorporating a strong pyrene absorption group into the matrix of graphdiyne,to obtain pyrenyl graphdiyne(Pyr-GDY)nanofibers through a modified Glaser-Hay coupling reaction of 1,3,6,8-tetraethynylpyrene(TEP)monomers.For comparison,phenyl graphdiyne(Phe-GDY)nanosheets were also constructed using 1,3,4,6-tetraethynylbenzene(TEB)as a monomer.Compared with Phe-GDY,Pyr-GDY exhibits a wider visible light absorption band,promoted efficiency of the charge separation/transport and more sufficient active sites for water reduction.As a result,Pyr-GDY alone displays superior photoelectrocatalytic performance for water splitting,giving a cathode photocurrent density of^138μA cm-2 at a potential of-0.1 Vversus normal hydrogen electrode(NHE)in neutral aqueous solution,which is almost ten and twelve times as high as those of Phe-GDY(14μA cm-2)and HEB-GDY(12μA cm-2),respectively.Such a performance is also superior to those of most reported carbonbased metal-free photocathode.The results of theoretical calculations reveal that the carbon atoms in the acetylene bonds are the active sites for proton reduction.This work offers a new strategy for the construction of graphdiyne-based metal-free photoelectrocatalysts with enhanced photoelectrocatalytic performance.

Porousβ-FeOOH nanotube stabilizing Au single atom for highefficiency nitrogen fixation

Electrochemical nitrogen reduction reaction(NRR)under ambient conditions is highly desirable to achieve sustainable ammonia(NH3)production via an alternative carbon free strategy.Single-atom catalysts(SACs)with super high atomic utilization and catalytic efficiency exhibit great potential for NRR.Herein,a high-performance NRR SAC is facilely prepared via a simple deposition method to anchor Au single atoms onto porousβ-FeOOH nanotubes.The resulting Au-SA/FeOOH can efficiently drive NRR under ambient conditions,and the NH3 yield reaches as high as 2,860μg·h^(-1)·mg_(Au)^(-1)at-0.4 V vs.reversible hydrogen electrode(RHE)with 14.2%faradaic efficiency,much superior to those of all the reported Au-based electrocatalysts.Systematic investigations demonstrate that the synergy of much enhanced N_(2)adsorption,directional electron export,and mass transfer ability in Au-SA/FeOOH greatly contributes to the superior NRR activity.This work highlights a new insight into the design of high efficient NRR electrocatalysts by combination of porous metal oxide matrix and highly active single-atom sites.

In-situ growth of PbI_(2) on ligand-free FAPbBr_(3) nanocrystals to significantly ameliorate the stability of CO_(2) photoreduction

Excellent optical properties involving strong visible light response and superior carrier transport endow metal halide perovskites(MHP)with a fascinating prospect in the field of photocatalysis.Nevertheless,the poor stability of MHP nanocrystals(NCs)in water-contained system,especially without the protection of long alkyl chain ligands,severely restricts their photocatalytic performance.In this context,we report an effortless strategy for the generation of ligand-free MHP NCs based photocatalyst with high water tolerance,by coating PbI_(2)on the surface of ligand-free formamidinium lead bromide(FAPb Br_(3))NCs via the facile procedure of in-situ conversion with the aid of ZnI_(2).Under the protection of PbI_(2)layer,the resultant FAPb Br_(3)/PbI_(2)composite exhibits significantly ameliorated stability in an artificial photosynthesis system with CO_(2)and H_(2)O vapor as feedstocks.Moreover,the formation of compact PbI_(2)layer can accelerate the separation of photogenerated carriers in FAPbBr_(3)NCs,bringing forth a remarkable improvement of CO_(2)photoreduction efficiency with an impressive electron consumption yield of 2053μmol/g in the absence of organic sacrificial agents,which is 7-fold over that of pristine FAPb Br_(3)NCs.

β-Cyclodextrin Decorated CdS Nanocrystals Boosting the Photocatalytic Conversion of Alcohols

Regarding the utilization of semiconductor nanocrystals(NCs)in photocatalysis,the significant challenge is to eliminate the hindrance of decorated surface ligands on the photocarrier transport while maintaining their overall stability.Herein,we report a novel and stable catalyst comprising CdS NCs and surfacebound mono-(6-mercapto-6-deoxy)-β-cyclodextrin(HS-β-CD)molecules(denoted as CdS-CD),which could convert alcohols selectively into diols or aldehydes and H2 under visible light irradiation,with 100%atomutilization,using an aqueous medium as a green solvent.The decoratedβ-CD ligands did not only confer a good stability of CdS-CD in water but also showed a high host–guest affinity to the alcohol species,thereby,guaranteeing a close vicinity of alcohol molecules at the surface of CdS NCs and minimizing the hindrance of surface ligands on the photocarrier transport.As a result,the CdS-CD displayed much improved photocatalytic activity for the conversion of alcohols in aqueous media,compared with those of CdS-BF_(4)NCs.

Heavy-Atom-Free Photosensitizers for High-Yield CO_(2)-to-CO Conversion

Heavy-Atom-Free photosensitizers(HAFPs)with abundant resources showgreat potential to construct noble metal-free and high-yield CO_(2)photoreduction systems,but have rarely been achieved due to their poor intersystem crossing(ISC)efficiency.Herein,a library of HAFPs(B-1-B-8)were rationally designed by coupling various anthracene donors and boron dipyrromethene acceptors to break the short-lived excited state limitation of pure organic chromophores.The special orthogonal geometry between electron donor and acceptor contributes totriggering spin-orbit charge transfer-induced ISCs to achieve long-lived triplet and reduced states,which can facilitate consecutive intermolecular electron transfers to further boost CO_(2)reduction.Impressively,the reduced HAFP B-8 can efficiently sensitize iron catalysts to construct noble metal-free photocatalytic systems for highly efficient and selective CO_(2)-to-CO conversion with 1311μmol yield.Experimental and theoretical investigations clearly illustrate the structure-activity relationship,highlighting a new avenue to develop highly efficient organic photosensitizers to boost CO_(2)photoreduction.