Transition Metal Oxides Nanowire Arrays For Efficient Electrocatalytic Hydrogen Evolution

Development of low-cost electrocatalysts toward oxygen evolution?OER?and hydrogen evolution reactions?HER?is crucial for large-scale and clean hydrogen production.Cost-effective and environment-friendly transition metal oxide-based catalysts are superbly active for OER,however,their applications in catalyzing HER remain challenging due to unsatisfactory activity and intrinsically poor electronic conductivity.?i?we report the synthesis of NiO nanorods?NRs?with abundant oxygen?O?vacancies via a facile cation exchange strategy.Based on the experimental studies and density functional theory calculations,we demonstrate that the chemical and electronic property of NiO NRs is successfully optimized through O-vacancy engineering,the O-vacancies on the surface of NiO NRs remarkably enhance their electronic conduction and promote HER reaction kinetics simultaneously.The resulting NiO NRs exhibit excellent alkaline HER catalytic activity and durability,it displays a small overpotential of¹10 mV to produce a HER current density of 10mA cm^-22 and shows a slight current attenuation of 6%after 10 h continuous testing.Furthermore,these specific designed NiO NRs in situ on carbon fiber paper substrates were directly employed as both HER and OER catalysts for overall water splitting,affording better performance than benchmark Pt and RuO₂ catalysts.?ii?Here we fabricated size-controlled Ni?Zn-doped CoO NRs directly on CFP substrate using dual and partial cation exchange in gas phase.By adjusting the exchange temperature and Ni,Co dual-source ratio control its doping content.HADDF-STEM results demonstrate that the synthesis of atomic-level doped ternary metal oxides,and maintained the single crystal structure.Furthermore,the performance of the water splitting is also outstanding.