Designing transition metal-oxide-based bifunctional electrocatalysts with excellent activity and stability for OER/HER to achieve efficient water splitting is of great importance for renewable energy technologies. Herein, a highly efficient bifunctional catalysts with oxygen-rich vacancies of nickel-decorated RuO 2 (NiRuO 2−x ) prepared by a unique one-pot glucose-blowing approach were investigated. Remarkably, the NiRuO 2−x catalysts exhibited excellent HER and OER activity at 10 mA cm −2 in alkaline solution with only a minimum overpotential of 51 mV and 245 mV, respectively. Furthermore, the NiRuO 2−x overall water splitting exhibited an ultra-low voltage of 1.6 V to obtain 10 mA cm −2 and stability for more than 10 h. XPS measurement and theoretical calculations demonstrated that the introduction of Ni-dopant and oxygen vacancies make the d-band center to lie close to the Fermi energy level, the chemical bonds between the active site and the adsorbed oxygen intermediate state are enhanced, thereby lowering the reaction activation barriers of HER and OER. The assembly of solar-driven alkaline electrolyzers facilitate the application of the NiRuO 2−x bifunctional catalysts.
Searching for highly efficient, stable and non-noble metal electrocatalysts for the hydrogen/oxygen evolution reaction (HER/OER) is crucial to renewable-energy conversion systems. Cobalt phosphosulfide (CoPS) is regarded as a promising electrocatalyst for the HER in acid solution. Nonetheless, there are no studies of its HER and OER activity in basic solution. Herein, we engineer a novel and highly efficient water splitting electrocatalyst of ultrafine CoPS nanoparticles (NPs) encapsulated in N, P, and S tri-doped porous carbon (CoPS@NPS-C) through metal–organic frameworks (MOFs) and commercial carbon black (XC-72) as precursors. The abundant and evenly distributed metals of MOFs form ultrafine CoPS NPs, and the rich N organic ligands of MOFs and XC-72 are shaped into the NPS-C to protect CoPS NPs leading to long-term stability in water-splitting applications. Meanwhile, the strong interaction between CoPS and NPS-C in this special structure not only ensures the high activity of the HER in acid solution and the OER in alkaline solution, but also maintains good HER performance in alkaline solution. The results display that the novel structure electrocatalyst of CoPS@NPS-C has great potential in water-splitting applications.