Key Words:D -band centerOxygen vacanciesHeterogeneous interfaceOverall water splittingHierarchical nanoarchitecture
Abstract:The rational design of highly active electrocatalysts for water electrolysis remains challenging for green hydrogen utilization. Herein, guided by the correlation between the electroactivity and the d-band center (E d ), a novel hierarchical nanoarchitecture (Ni 2 P/NiFe 2 O 4-V O @N-GTs) was fabricated, in which, Ni 2 P nanoparticles are grown on the oxygen vacancy-rich NiFe 2 O 4 nanosheet arrays anchoring on N-doping graphene tubes. The results reveal that the multiple strategies including the vacancies and heterogeneous interface construction effectively induce the charge redistribution, and further adjust the E d to the appropriate energy level, which endows the optimal balance between the adsorption and desorption ability of the catalyst to reaction intermediates, thus leading to the conspicuous electrocatalytic activity. Additionally, the hierarchical nanoarchitecture contributes to the exposure of more active sites, the efficiency of electron transfer, and the release of generated gas. Hence, Ni 2 P/NiFe 2 O 4-V O @N-GTs presents superior bifunctional activity, especially a low overpotential of 194 mV at 10 mA cm-2 for OER. The corresponding overall water electrolyzer owns a lower cell voltage and long-term durability with continuously operating over 330 h at 100 mA cm-2 , outperforming the most reported bifunctional electrocatalysts. This work presents an effective pathway for regulating the E d through multiple strategies to improve the catalytic performance of catalysts.
Volume:80
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Translation or Not:no