Multiple strategies regulating the d-band center of Ni2P/NiFe2O4 @N-GTs hierarchical nanoarchitecture as efficient electrocatalyst for overall water splitting

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.