The harsh corrosive environment and sluggish oxygen evolution reaction(OER)kinetics at the anode of proton exchange membrane water electrolysis(PEMWE)cells warrant the use of excess Ir,thereby hindering large-scale in...The harsh corrosive environment and sluggish oxygen evolution reaction(OER)kinetics at the anode of proton exchange membrane water electrolysis(PEMWE)cells warrant the use of excess Ir,thereby hindering large-scale industrialization.To mitigate these issues,the present study aimed at fabricating a robust low-Ir-loading electrode via one-pot synthesis for efficient PEMWE.The pre-electrode was first prepared by alloying through the co-electrodeposition of Ir and Co,followed by the fabrication of Ir–Co oxide(Co-incorporated Ir oxide)electrodes via electrochemical dealloying.Two distinct dealloying techniques resulted in a modified valence state of Ir,and the effects of Co incorporation on the activity and stability of the OER catalysts were clarified using density functional theory(DFT)calculations,which offered theoretical insights into the reaction mechanism.While direct experimental validation of the oxygen evolution mechanism remains challenging under the current conditions,DFT-based theoretical modeling provided valuable perspectives on how Co incorporation could influence key steps in oxygen evolution catalysis.The Ir–Co oxide electrode with a selectively modulated valence state showed impressive performance with an overpotential of 258 mV at 10 mA cm^(−2),a low Tafel slope of 29.4 mV dec^(−1),and stability for 100 h at 100 mA cm^(−2)in the OER,in addition to a low overpotential of 16 mV at−10 mA cm^(−2)and high stability for 24 h in the hydrogen evolution reaction.The PEMWE cell equipped with the bifunctional Ir–Co oxide electrode as the anode and cathode exhibited outstanding performance(11.4 A cm^(−2)at 2.3 Vcell)despite having a low noble-metal content of 0.4 mgNM cm^(−2).展开更多
CO adsorption on β zeolite with highly dispersed CuCl 2·2H 2O was studied by IR spectroscopy. The results of XRD and 29 Si NMR indicate that CuCl 2·2H 2O is highly dispersed into β zeolite channel as a mon...CO adsorption on β zeolite with highly dispersed CuCl 2·2H 2O was studied by IR spectroscopy. The results of XRD and 29 Si NMR indicate that CuCl 2·2H 2O is highly dispersed into β zeolite channel as a monolayer. The IR spectra of adsorbed CO on the zeolites demonstrate that two distinct types of adsorption sites exist in the zeolites, i.e ., cation and non cation exchange sites. Two simultaneous processes, solid phase ion exchange and molecular diffusion, are involved in the dispersion of CuCl 2·2H 2O.展开更多
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(RS-2024-00340074,RS-2024-00409901,2022M3I3A1081901,and RS-2024-00413272)。
文摘The harsh corrosive environment and sluggish oxygen evolution reaction(OER)kinetics at the anode of proton exchange membrane water electrolysis(PEMWE)cells warrant the use of excess Ir,thereby hindering large-scale industrialization.To mitigate these issues,the present study aimed at fabricating a robust low-Ir-loading electrode via one-pot synthesis for efficient PEMWE.The pre-electrode was first prepared by alloying through the co-electrodeposition of Ir and Co,followed by the fabrication of Ir–Co oxide(Co-incorporated Ir oxide)electrodes via electrochemical dealloying.Two distinct dealloying techniques resulted in a modified valence state of Ir,and the effects of Co incorporation on the activity and stability of the OER catalysts were clarified using density functional theory(DFT)calculations,which offered theoretical insights into the reaction mechanism.While direct experimental validation of the oxygen evolution mechanism remains challenging under the current conditions,DFT-based theoretical modeling provided valuable perspectives on how Co incorporation could influence key steps in oxygen evolution catalysis.The Ir–Co oxide electrode with a selectively modulated valence state showed impressive performance with an overpotential of 258 mV at 10 mA cm^(−2),a low Tafel slope of 29.4 mV dec^(−1),and stability for 100 h at 100 mA cm^(−2)in the OER,in addition to a low overpotential of 16 mV at−10 mA cm^(−2)and high stability for 24 h in the hydrogen evolution reaction.The PEMWE cell equipped with the bifunctional Ir–Co oxide electrode as the anode and cathode exhibited outstanding performance(11.4 A cm^(−2)at 2.3 Vcell)despite having a low noble-metal content of 0.4 mgNM cm^(−2).
文摘CO adsorption on β zeolite with highly dispersed CuCl 2·2H 2O was studied by IR spectroscopy. The results of XRD and 29 Si NMR indicate that CuCl 2·2H 2O is highly dispersed into β zeolite channel as a monolayer. The IR spectra of adsorbed CO on the zeolites demonstrate that two distinct types of adsorption sites exist in the zeolites, i.e ., cation and non cation exchange sites. Two simultaneous processes, solid phase ion exchange and molecular diffusion, are involved in the dispersion of CuCl 2·2H 2O.
