We report the discovery of bulk superconductivity in a new quinary intermetallic compound Th_(2)Mo_(2)Ru_(2)Si_(4)C,crystallized in a collapsed 22241-type structure.This structure is characterized by the intergrowth o...We report the discovery of bulk superconductivity in a new quinary intermetallic compound Th_(2)Mo_(2)Ru_(2)Si_(4)C,crystallized in a collapsed 22241-type structure.This structure is characterized by the intergrowth of ThMo_(2)Si_(2)C and ThRu_(2)Si_(2) units interconnected by equivalent Si-Si bonds that enhance inter-sublattice coupling.The refined lattice parameters are a=4.2212(1)Å and c=20.3899(7)Å.Electrical resistivity and magnetic susceptibility measurements of both polycrystalline and single-crystal samples consistently demonstrate bulk superconductivity with a transition temperature T_(c)∼6.0 K significantly higher than those of the constituent compound ThMo_(2)Si_(2)C and its related analogs.Under magnetic fields,the superconducting state exhibits a nearly isotropic behavior,which is attributed to strong covalent interlayer coupling.First-principles calculations reveal a substantial contribution from the Mo-d orbitals near the Fermi level,which exhibit several band-crossing points.The enhancement in T_(c) can be attributed to the synergistic combination of the valence electron concentration and the inter-sublattice self-doping effect between the[Ru_(2)Si_(2)]and[Mo_(2)Si_(2)C]layers.展开更多
Efficient alkaline hydrogen evolution reaction(HER)catalysts are critical for anion exchange membrane water electrolysis(AEMWE).However,the intrinsic scaling relationship between water dissociation and OH desorption f...Efficient alkaline hydrogen evolution reaction(HER)catalysts are critical for anion exchange membrane water electrolysis(AEMWE).However,the intrinsic scaling relationship between water dissociation and OH desorption fundamentally impedes designing catalysts requiring concurrent superior water dissociation and facile OH desorption.Here,we engineer a superhydrophilic Ru/Cr_(2)O_(3) heterostructured electrocatalyst through in situ confinement of Ru nanoparticles(5-10 nm)within a Cr_(2)O_(3) matrix.Acting as a Lewis acid,the Cr_(2)O_(3) component provides alternative sites for water dissociation,accelerating the Volmer step kinetics and downshifting the Ru d-band center via interfacial charge transfer,while simultaneously adsorbing OH-to form a surface-bound Lewis base that repels excess OH-from Ru sites,thereby suppressing hydroxyl over-adsorption.Concurrently,the superhydrophilic surface architecture promotes efficient hydrogen bubble release,thereby reducing mass transport resistance.As a result,the Ru/Cr_(2)O_(3) heterostructured electrocatalyst exhibits an ultralow overpotential of 36.7 mV at 10 mA cm^(-2) and a Tafel slope of 33.2 mV dec^(-1).Integrated into an AEMWE device,the electrode delivers500 mA cm^(-2) for 2000 h in 1.0 M KOH,underscoring its industrial viability(hydrogen production energy consumption per cubic meter(EW):3.94 kW h m^(-3);electricity-to-hydrogen energy conversion efficiency(η_(ETH)):89%@80℃).展开更多
The hydrazine oxidation reaction(HzOR)has garnered significant attention as a feasible approach to replace sluggish anodic reactions to save energy.Nevertheless,there are still difficulties in developing highly effici...The hydrazine oxidation reaction(HzOR)has garnered significant attention as a feasible approach to replace sluggish anodic reactions to save energy.Nevertheless,there are still difficulties in developing highly efficient catalysts for the HzOR.Herein,we report amorphous ruthenium nanosheets(a-Ru NSs)with a thickness of approximately 9.6 nm.As a superior bifunctional electrocatalyst,a-Ru NSs exhibited enhanced electrocatalytic performance toward both the HzOR and hydrogen evolution reaction(HER),outperforming benchmark Pt/C catalysts,where the a-Ru NSs achieved a work-ing potential of merely-76 mV and a low overpotential of only 17 mV to attain a current density of 10 mA·cm^(-2) for the HzOR and HER,respectively.Furthermore,a-Ru NSs displayed a low cell voltage of 28 mV at 10 mA·cm^(-2) for overall hy-drazine splitting in a two-electrode electrolyzer.In situ Raman spectra revealed that the a-Ru NSs can efficiently promote N‒N bond cleavage,thereby producing more*NH_(2)and accelerating the progress of the reaction.展开更多
Propane dehydrogenation(PDH)is a vital industrial process for producing propene,utilizing primarily Cr-based or Pt-based catalysts.These catalysts often suffer from challenges such as the toxicity of Cr,the high costs...Propane dehydrogenation(PDH)is a vital industrial process for producing propene,utilizing primarily Cr-based or Pt-based catalysts.These catalysts often suffer from challenges such as the toxicity of Cr,the high costs of noble metals like Pt,and deactivation issues due to sintering or coke formation at elevated temperatures.We introduce an exceptional Ru-based catalyst,Ru nanoparticles anchored on a nitrogendoped carbon matrix(Ru@NC),which achieves a propane conversion rate of 32.2%and a propene selectivity of 93.1%at 550°C,with minimal coke deposition and a low deactivation rate of 0.0065 h^(-1).Characterizations using techniques like TEM and XPS,along with carefully-designed controlled experiments,reveal that the notable performance of Ru@NC stems from the modified electronic state of Ru by nitrogen dopant and the microporous nature of the matrix,positioning it as a top contender among state-of-the-art PDH catalysts.展开更多
基金supported by the National Key Research and Development Program of China (Grant Nos.2022YFA1403202 and 2023YFA1406101)the CAS Superconducting Research Project (Grant No.SCZX-0101)。
文摘We report the discovery of bulk superconductivity in a new quinary intermetallic compound Th_(2)Mo_(2)Ru_(2)Si_(4)C,crystallized in a collapsed 22241-type structure.This structure is characterized by the intergrowth of ThMo_(2)Si_(2)C and ThRu_(2)Si_(2) units interconnected by equivalent Si-Si bonds that enhance inter-sublattice coupling.The refined lattice parameters are a=4.2212(1)Å and c=20.3899(7)Å.Electrical resistivity and magnetic susceptibility measurements of both polycrystalline and single-crystal samples consistently demonstrate bulk superconductivity with a transition temperature T_(c)∼6.0 K significantly higher than those of the constituent compound ThMo_(2)Si_(2)C and its related analogs.Under magnetic fields,the superconducting state exhibits a nearly isotropic behavior,which is attributed to strong covalent interlayer coupling.First-principles calculations reveal a substantial contribution from the Mo-d orbitals near the Fermi level,which exhibit several band-crossing points.The enhancement in T_(c) can be attributed to the synergistic combination of the valence electron concentration and the inter-sublattice self-doping effect between the[Ru_(2)Si_(2)]and[Mo_(2)Si_(2)C]layers.
基金supported by the National Natural Science Foundation of China(22479113,52101268)the Fundamental Research Funds for the Central Universities(buctrc202323)。
文摘Efficient alkaline hydrogen evolution reaction(HER)catalysts are critical for anion exchange membrane water electrolysis(AEMWE).However,the intrinsic scaling relationship between water dissociation and OH desorption fundamentally impedes designing catalysts requiring concurrent superior water dissociation and facile OH desorption.Here,we engineer a superhydrophilic Ru/Cr_(2)O_(3) heterostructured electrocatalyst through in situ confinement of Ru nanoparticles(5-10 nm)within a Cr_(2)O_(3) matrix.Acting as a Lewis acid,the Cr_(2)O_(3) component provides alternative sites for water dissociation,accelerating the Volmer step kinetics and downshifting the Ru d-band center via interfacial charge transfer,while simultaneously adsorbing OH-to form a surface-bound Lewis base that repels excess OH-from Ru sites,thereby suppressing hydroxyl over-adsorption.Concurrently,the superhydrophilic surface architecture promotes efficient hydrogen bubble release,thereby reducing mass transport resistance.As a result,the Ru/Cr_(2)O_(3) heterostructured electrocatalyst exhibits an ultralow overpotential of 36.7 mV at 10 mA cm^(-2) and a Tafel slope of 33.2 mV dec^(-1).Integrated into an AEMWE device,the electrode delivers500 mA cm^(-2) for 2000 h in 1.0 M KOH,underscoring its industrial viability(hydrogen production energy consumption per cubic meter(EW):3.94 kW h m^(-3);electricity-to-hydrogen energy conversion efficiency(η_(ETH)):89%@80℃).
基金supported by the National Key R&D Program of China(2018YFA0702001)National Natural Science Foundation of China(22371268,22301287)+3 种基金Fundamental Research Funds for the Central Universities(WK2060000016)Anhui Provincial Natural Science Foundation(2208085J09,2208085QB33)Collaborative Innovation Program of Hefei Science Center,CAS(2022HSC-CIP020)Youth Innovation Promotion Association of the Chinese Academy of Science(2018494)and USTC Tang Scholar.
文摘The hydrazine oxidation reaction(HzOR)has garnered significant attention as a feasible approach to replace sluggish anodic reactions to save energy.Nevertheless,there are still difficulties in developing highly efficient catalysts for the HzOR.Herein,we report amorphous ruthenium nanosheets(a-Ru NSs)with a thickness of approximately 9.6 nm.As a superior bifunctional electrocatalyst,a-Ru NSs exhibited enhanced electrocatalytic performance toward both the HzOR and hydrogen evolution reaction(HER),outperforming benchmark Pt/C catalysts,where the a-Ru NSs achieved a work-ing potential of merely-76 mV and a low overpotential of only 17 mV to attain a current density of 10 mA·cm^(-2) for the HzOR and HER,respectively.Furthermore,a-Ru NSs displayed a low cell voltage of 28 mV at 10 mA·cm^(-2) for overall hy-drazine splitting in a two-electrode electrolyzer.In situ Raman spectra revealed that the a-Ru NSs can efficiently promote N‒N bond cleavage,thereby producing more*NH_(2)and accelerating the progress of the reaction.
基金supported by the National Key Research and Development Project of China(No.2022YFE0113800)the National Natural Science Foundation of China(No.22102013)+2 种基金Natural Science Foundation of Chongqing(No.cstc2021jcyj-msxmX0945)Venture and Innovation Support Program for Chongqing Overseas Returnees(No.cx2020107)Thousand Talents Program for Distinguished Young Scholars,Postdoctoral Fellowship Program of CPSF(No.GZB20230910)。
文摘Propane dehydrogenation(PDH)is a vital industrial process for producing propene,utilizing primarily Cr-based or Pt-based catalysts.These catalysts often suffer from challenges such as the toxicity of Cr,the high costs of noble metals like Pt,and deactivation issues due to sintering or coke formation at elevated temperatures.We introduce an exceptional Ru-based catalyst,Ru nanoparticles anchored on a nitrogendoped carbon matrix(Ru@NC),which achieves a propane conversion rate of 32.2%and a propene selectivity of 93.1%at 550°C,with minimal coke deposition and a low deactivation rate of 0.0065 h^(-1).Characterizations using techniques like TEM and XPS,along with carefully-designed controlled experiments,reveal that the notable performance of Ru@NC stems from the modified electronic state of Ru by nitrogen dopant and the microporous nature of the matrix,positioning it as a top contender among state-of-the-art PDH catalysts.
