Phosphorus modified hollow, porous Nickel-Cobalt oxides nanocubes with heterostructure for oxygen evolution reaction in alkaline

Abstract

The development of efficient non-noble-metal based catalysts for oxygen evolution reaction is the crucial issue to promote electrolytic water technology. Herein, an effective phosphorus-modified hollow porous Nickel-Cobalt oxides nanocube was prepared by thermal oxidation and partial phosphorization processes. The optimal P-NiO/NiCo2O4 nanocube disclosed remarkable electrochemical activity for OER in 1.0 M KOH with a low overpotential of 290 mV at 10 mA cm−2, a low Tafel slope of 49.6 mV dec−1, and good long-life stability for 20 h. Based on the experimental and theoretical calculation results, the introduction of P was proved to be the key to the excellent electrochemical activity for OER. P doping could optimize the adsorption of the intermediates, decrease the energy barrier and change the rate-determining step. Meanwhile, the P-dopant could modulate the electronic structure and enhance the conductivity of NiO/NiCo2O4. In addition, hollow, porous hybrid structure and oxygen vacancies could increase the number of active sites exposed, and facilitate the ion transport. The present work provides a valuable strategy to design transition-metal oxide based electrocatalysts with enhanced electrocatalytic performances by controlling partial P doping.