Template-free synthesis of Co3O4 microtubes for enhanced oxygen evolution reaction

To fully exploit the superiority of tubular structures, in this study, we systematically explore the optimal preparation conditions for Ni/Co 3 O 4 , including cation species and content, additive species and content, and anion species. Our results reveal that the formation of an initial cobalt nickel acetate hydroxide prism is the key factor and directly affects the final microtubular structure. Moreover, P is subsequently doped into the Ni/Co 3 O 4 lattice to increase the M 3+ /M 2+ molar ratio (M = Co and Ni), promote reaction kinetics, and optimize electronic structure. Consequently, the oxygen evolution reaction performance of P-doped tubular Ni/Co 3 O 4 is significantly higher than that of undoped Ni/Co 3 O 4 and the state-of-the-art RuO 2 electrocatalyst.