Utilizing plasmonic non-noble metal nanoparticles(NPs)for photocatalytic hydrogen evolution reaction is a significant step toward green energy production.However,optimizing the interface between non-noble metal NPs an...Utilizing plasmonic non-noble metal nanoparticles(NPs)for photocatalytic hydrogen evolution reaction is a significant step toward green energy production.However,optimizing the interface between non-noble metal NPs and semiconducting materials in metal-semiconductor composites remains challenging owing to the inevitable surface oxide layers of non-noble metal NPs because the surface oxide layers of non-noble metal NPs can suppress the transfer of photoinduced carriers,leading to poor photocatalytic performance.Herein,we propose a photoinduced interface activation strategy to reduce the number of oxide layers based on a dynamic charge-transfer mechanism under illumination conditions,with Bi NPs and a Ni-based metal-organic framework(MOF)selected as model materials.Under light illumination,the photoinduced charges and plasmonic hot electrons heavily pooled at the interface between the Bi NPs and Ni-MOF,resulting in the reduction of the oxide layer on the surface of Bi,thus attenuating its hindering effect on charge transfer.This phenomenon led to a dynamically enhanced carrier concentration in the Bi/Ni-MOF composite,with an outstanding photocatalytic hydrogen evolution rate of 5822μmol g^(−1)h^(−1)achieved with the composite.The results of this study indicate that our strategy provides a new method for optimizing plasmonic non-noble metal Bi NPs with oxide layers.展开更多
Due to their high capacity,the P2-type layered oxide cathodes containing oxygen redox reaction processes have attracted wide attention for sodium-ion batteries.However,these materials usually exhibit poor electro-chem...Due to their high capacity,the P2-type layered oxide cathodes containing oxygen redox reaction processes have attracted wide attention for sodium-ion batteries.However,these materials usually exhibit poor electro-chemical properties,resulting from irreversible oxygen redox reactions and phase transition processes at high voltages,and thus hinder their large-scale application.This work reveals the mechanism for the significantly improved cycle stability and rate performance of Co/Ni-free Na_(0.7)5Li_(0.25-2/3x)CuxMn_(0.75-1/3x)O_(2)via Cu doping.Ex-situ XPS demonstrates that Cu doping reduces the amount of Mn^(3+)that triggers the Jahn-Teller effect during the cycling.In addition,the electron enrichment of oxygen around Cu can alleviate the irreversible oxidation of oxygen,and thus suppressing the phase transition originates from the rapid weakening of the electrostatic repulsion between O-O.Meanwhile,in-situ XRD results verify that the Na_(0.7)5Li_(0.19)Cu_(0.09)Mn_(0.7)2O_(2)maintains the P2 phase structure during charging and discharging,resulting in a near-zero strain characteristic of 1.9%.Therefore,the optimized cathode delivers a high reversible capacity of 194.9 mAh g−1 at 0.1 C and excellent capacity retention of 88.6%after 100 cycles at 5 C.The full cell paired with commercial hard carbon anode delivers energy density of 240 Wh kg−1.Our research provides an idea for designing a new type of intercalated cathode for sodium-ion batteries with low cost and high energy density.展开更多
基金supported by the Youth Natural Science Foundation of Shanxi Province(202103021223053)the National Natural Science Foundation of China(NSFC 22271211,22305169)the 1331 Project of Shanxi Province。
文摘Utilizing plasmonic non-noble metal nanoparticles(NPs)for photocatalytic hydrogen evolution reaction is a significant step toward green energy production.However,optimizing the interface between non-noble metal NPs and semiconducting materials in metal-semiconductor composites remains challenging owing to the inevitable surface oxide layers of non-noble metal NPs because the surface oxide layers of non-noble metal NPs can suppress the transfer of photoinduced carriers,leading to poor photocatalytic performance.Herein,we propose a photoinduced interface activation strategy to reduce the number of oxide layers based on a dynamic charge-transfer mechanism under illumination conditions,with Bi NPs and a Ni-based metal-organic framework(MOF)selected as model materials.Under light illumination,the photoinduced charges and plasmonic hot electrons heavily pooled at the interface between the Bi NPs and Ni-MOF,resulting in the reduction of the oxide layer on the surface of Bi,thus attenuating its hindering effect on charge transfer.This phenomenon led to a dynamically enhanced carrier concentration in the Bi/Ni-MOF composite,with an outstanding photocatalytic hydrogen evolution rate of 5822μmol g^(−1)h^(−1)achieved with the composite.The results of this study indicate that our strategy provides a new method for optimizing plasmonic non-noble metal Bi NPs with oxide layers.
基金financially supported by the National Natural Science Foundation of China(22271211)the Natural Science Foundation of Shanxi Province(20210302123107 and 202202060301018)。
文摘Due to their high capacity,the P2-type layered oxide cathodes containing oxygen redox reaction processes have attracted wide attention for sodium-ion batteries.However,these materials usually exhibit poor electro-chemical properties,resulting from irreversible oxygen redox reactions and phase transition processes at high voltages,and thus hinder their large-scale application.This work reveals the mechanism for the significantly improved cycle stability and rate performance of Co/Ni-free Na_(0.7)5Li_(0.25-2/3x)CuxMn_(0.75-1/3x)O_(2)via Cu doping.Ex-situ XPS demonstrates that Cu doping reduces the amount of Mn^(3+)that triggers the Jahn-Teller effect during the cycling.In addition,the electron enrichment of oxygen around Cu can alleviate the irreversible oxidation of oxygen,and thus suppressing the phase transition originates from the rapid weakening of the electrostatic repulsion between O-O.Meanwhile,in-situ XRD results verify that the Na_(0.7)5Li_(0.19)Cu_(0.09)Mn_(0.7)2O_(2)maintains the P2 phase structure during charging and discharging,resulting in a near-zero strain characteristic of 1.9%.Therefore,the optimized cathode delivers a high reversible capacity of 194.9 mAh g−1 at 0.1 C and excellent capacity retention of 88.6%after 100 cycles at 5 C.The full cell paired with commercial hard carbon anode delivers energy density of 240 Wh kg−1.Our research provides an idea for designing a new type of intercalated cathode for sodium-ion batteries with low cost and high energy density.
