Search

Exploring efficient transition-metal-based electrocatalysts for oxygen evolution reaction (OER) is imperative but remain challenging for sustainable energy storage and conversion systems. Foreign species doping is a significant regulation strategy to enhance the intrinsic activity of host matrix. However, the potential relationship of structure-activity caused by guest doping elements is seldom tracked systematically. In this case, both theoretical screening and experimental verification are complementarily employed to investigate the guest doping effects of ten first-row transition metals (Sc~Zn) on bimetallic NiCo layered double hydroxide (NiCo-LDH). As a result, the optimized Fe-doped NiCo-LDH is identified as the most promising candidate toward alkaline electrocatalytic OER, which exhibits the quasi-industrial current density of 1000 mA cm-2 at overpotential of400 mV. Meanwhile, it also shows impressively long-term stability of 500 h at 500 mA cm-2 with a negligible activity loss. Moreover, in situ electrochemical Raman spectroscopy unveils the dynamic structure evolution from pre-catalytic state (Fe-NiCo-LDH) to metal oxyhydroxide (Fe-(NiCo)OOH) during the oxidation reaction, and ab-initio molecular dynamics simulations are further performed to confirm the thermodynamic stability of activated Fe-(NiCo)OOH phase. This work provides a promising platform for exploring the critical role of transition metal guest doping on host matrix in developing industrially required OER electrocatalysts. [ABSTRACT FROM AUTHOR]

Electrochemical carbon dioxide reduction reaction (CO2RR) provides a promising pathway for both decreasing atmospheric CO2 concentration and producing valuable carbon‐based fuels. To explore efficient and cost‐effective catalysts for electrochemical CO2RR is of great importance, but remains challenging. Se‐doped carbon nanosheets (Se‐CNs) with a micro‐, meso‐, and macroporous structure are proposed for electrochemical CO2RR. Such an electrocatalyst combines the advantages of Se optimized active sites, hierarchical pores for facilitating reactant or ion penetration, transport and reaction, and large surface area for more accessible active sites. This Se‐CNs electrocatalyst exhibits over 11‐times enhanced partial current density of CO than the CNs without Se doping and high selectivity (90%) for CO2 electroreduction to CO at a low potential of −0.6 V versus the reversible hydrogen electrode (vs RHE). Density function theoretical calculations reveal that the Se introduction in CNs lowers the free energy barrier of CO2RR and inhibits hydrogen evolution reaction effectively, thus improving the selectivity for CO2 reduction to CO. This work presents a new member of the metal‐free electrocatalyst family, which is easily prepared, low cost, adjustable, and highly efficient for CO2RR. [ABSTRACT FROM AUTHOR]