To address the high cost and limited electrochemical endurance of Pt-based electrocatalysts,the appropriate introduction of transition metal-based compounds as supports to disperse and anchor Pt species offers a promi...To address the high cost and limited electrochemical endurance of Pt-based electrocatalysts,the appropriate introduction of transition metal-based compounds as supports to disperse and anchor Pt species offers a promising approach for improving catalytic efficiency.In this study,sub-1 nm Pt nanoclusters were uniformly confined on NiO supports with a hierarchical nanotube/nanosheet structure(Pt/NiO/NF)through a combination of spatial domain confinement and annealing.The resulting catalyst exhibited excellent electrocatalytic activity and stability for hydrogen evolution(HER)and urea oxidation reactions(UOR)under alkaline conditions.Structural characterization and density functional theory calculations demonstrated that sub-1 nm Pt nanoclusters were immobilized on the NiO supports by Pt–O–Ni bonds at the interface.The strong metal-support interaction induced massive charge redistribution around the heterointerface,leading to the formation of multiple active sites.The Pt/NiO/NF catalyst only required an overpotential of 12 and 136 mV to actuate current densities of 10 and 100 mA cm^(-2) for the HER,respectively,and maintained a voltage retention of 96%for 260 h of continuous operation at a current density of 500 mA cm^(-2).Notably,in energy-efficient hydrogen production systems coupled with the HER and UOR,the catalyst required cell voltages of 1.37 and 1.53 V to drive current densities of 10 and 50 mA cm^(-2),respectively—approximately 300 mV lower than conventional water electrolysis systems.This study presents a novel pathway for designing highly efficient and robust sub-nanometer metal cluster catalysts.展开更多
Complex-shaped optical lenses are of great interest in the areas of laser processing,machine vision,and optical communications.Traditionally,the processing of complex optical lenses is usually achieved by precision ma...Complex-shaped optical lenses are of great interest in the areas of laser processing,machine vision,and optical communications.Traditionally,the processing of complex optical lenses is usually achieved by precision machining combined with post-grinding or polishing,which is expensive,labor-intensive and difficult in the processing of ultra-complex optical lenses.Additive manufacturing is an emerging technology that provides significant advantages in producing highly intricate optical devices.However,the layer-by-layer method employed in such manufacturing processes has resulted in low printing speeds,as well as limitations in surface quality.To address these challenges,we apply tomographic volumetric printing(TVP)in this work,which can realize the integrated printing of complex structural models without layering.By coordinating the TVP and the meniscus equilibrium post-curing methods,ultra-fast fabrication of complex-shaped lenses with sub-nanometric roughness has been achieved.A2.5 mm high,outer diameter 9 mm spherical lens with a roughness value of RMS=0.3340 nm is printed at a speed of 3.1×10^(4)mm^(3)h^(-1).As a further demonstration,a complex-shaped fly-eye lens is fabricated without any part assembly.The designed spherical lens is mounted on a smartphone’s camera,and the precise alignments above the circuit board are captured.Upon further optimization,this new technology demonstrates the potential for rapid fabrication of ultra-smooth complex optical devices or systems.展开更多
Owing to the need for regenerant and self-reduction problem,the hydrogen performance of sub-nano-sized trinuclear iron-oxo complexes is still far from satisfied with affordability and practicality.Herein,two binary ph...Owing to the need for regenerant and self-reduction problem,the hydrogen performance of sub-nano-sized trinuclear iron-oxo complexes is still far from satisfied with affordability and practicality.Herein,two binary photocatalytic systems based on trinuclear metal-oxo complexes have been first constructed and experimentally confirmed to be competent for seawater hydrogen evolution(715.4and271.9μmol of hydrogen can be found,respectively,after 48h).Notably,chloride ions act as the hole catcher and move into the gas phase in the stable form of chlorine.Similar to heterogeneous structures,homogeneous systemsnot only enhance the hydrogen performance while ensuring the stability of metal-oxo complexes,but also shorten the consumption of photogenerated carriers by dissolved impurities in the seawater.This new attempt of building pluralistic sub-nanometric systems may offer novel design strategies with noble-metal-free catalysts and low-cost candidates for traditional semiconductor materials in enhancing photocatalytic efficiency and performing chlorine evolution from seawater splitting.展开更多
文摘To address the high cost and limited electrochemical endurance of Pt-based electrocatalysts,the appropriate introduction of transition metal-based compounds as supports to disperse and anchor Pt species offers a promising approach for improving catalytic efficiency.In this study,sub-1 nm Pt nanoclusters were uniformly confined on NiO supports with a hierarchical nanotube/nanosheet structure(Pt/NiO/NF)through a combination of spatial domain confinement and annealing.The resulting catalyst exhibited excellent electrocatalytic activity and stability for hydrogen evolution(HER)and urea oxidation reactions(UOR)under alkaline conditions.Structural characterization and density functional theory calculations demonstrated that sub-1 nm Pt nanoclusters were immobilized on the NiO supports by Pt–O–Ni bonds at the interface.The strong metal-support interaction induced massive charge redistribution around the heterointerface,leading to the formation of multiple active sites.The Pt/NiO/NF catalyst only required an overpotential of 12 and 136 mV to actuate current densities of 10 and 100 mA cm^(-2) for the HER,respectively,and maintained a voltage retention of 96%for 260 h of continuous operation at a current density of 500 mA cm^(-2).Notably,in energy-efficient hydrogen production systems coupled with the HER and UOR,the catalyst required cell voltages of 1.37 and 1.53 V to drive current densities of 10 and 50 mA cm^(-2),respectively—approximately 300 mV lower than conventional water electrolysis systems.This study presents a novel pathway for designing highly efficient and robust sub-nanometer metal cluster catalysts.
基金supported by the National Natural Science Foundation of China(Grant No.51875253 and No.51935012)the Jiangsu Provincial Key Research and Development Program(BE2022069-2)the Western Light Project of Chinese Academy of Sciences(sbzg-zdsys-202007)。
文摘Complex-shaped optical lenses are of great interest in the areas of laser processing,machine vision,and optical communications.Traditionally,the processing of complex optical lenses is usually achieved by precision machining combined with post-grinding or polishing,which is expensive,labor-intensive and difficult in the processing of ultra-complex optical lenses.Additive manufacturing is an emerging technology that provides significant advantages in producing highly intricate optical devices.However,the layer-by-layer method employed in such manufacturing processes has resulted in low printing speeds,as well as limitations in surface quality.To address these challenges,we apply tomographic volumetric printing(TVP)in this work,which can realize the integrated printing of complex structural models without layering.By coordinating the TVP and the meniscus equilibrium post-curing methods,ultra-fast fabrication of complex-shaped lenses with sub-nanometric roughness has been achieved.A2.5 mm high,outer diameter 9 mm spherical lens with a roughness value of RMS=0.3340 nm is printed at a speed of 3.1×10^(4)mm^(3)h^(-1).As a further demonstration,a complex-shaped fly-eye lens is fabricated without any part assembly.The designed spherical lens is mounted on a smartphone’s camera,and the precise alignments above the circuit board are captured.Upon further optimization,this new technology demonstrates the potential for rapid fabrication of ultra-smooth complex optical devices or systems.
基金This work was supported by the National Natural Sci-ence Foundation of China(No.52071171)Liaoning Revitalization Talents Program-Pan Deng Scholars(XLYC1802005)+6 种基金Liaoning BaiQianWan Talents Program(LNBQW2018B0048)Natural Science Fund of Liaoning Province for Excellent Young Scholars(2019-YQ-04)Key ProjectofScientificResearchoftheEducationDepartment of Liaoning Province(LZD201902)Shenyang Science and Technology Project(21-108-9-04)Australian Research Council(ARC)through Future Fellowship(FT210100298)Discovery Project(DP220100603)Linkage Project(LP210200504)schemes,CSIRO Energy Centre and Kick-Start Project.
文摘Owing to the need for regenerant and self-reduction problem,the hydrogen performance of sub-nano-sized trinuclear iron-oxo complexes is still far from satisfied with affordability and practicality.Herein,two binary photocatalytic systems based on trinuclear metal-oxo complexes have been first constructed and experimentally confirmed to be competent for seawater hydrogen evolution(715.4and271.9μmol of hydrogen can be found,respectively,after 48h).Notably,chloride ions act as the hole catcher and move into the gas phase in the stable form of chlorine.Similar to heterogeneous structures,homogeneous systemsnot only enhance the hydrogen performance while ensuring the stability of metal-oxo complexes,but also shorten the consumption of photogenerated carriers by dissolved impurities in the seawater.This new attempt of building pluralistic sub-nanometric systems may offer novel design strategies with noble-metal-free catalysts and low-cost candidates for traditional semiconductor materials in enhancing photocatalytic efficiency and performing chlorine evolution from seawater splitting.
