Efficient and low-cost electrocatalysts for oxygen evolution reaction (OER), particularly in neutral conditions, are of significant importance for renewable energy technologies such as CO2 reduction and seawater splitting electrolysis. High-valent transition-metal sites have been considered as OER active sites; however, the rational design and construction of these sites remain a big challenge. Here, we report a trimetallic NiFeCu oxyhydroxide electrocatalyst, in which high-valent Ni sites are promoted and stabilized by the atomically embedded Cu, as evidenced by X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. Through compositional optimization, Ni6Fe1Cu1 catalysts achieved an overpotential of 385 mV at 10 mA cm–2, a Tafel slope of 164 mV dec–1, and a stability of 100 h at pH = 7.2. Density function theory calculations demonstrated that the Cu-doping facilitates the formation of high-valent Ni and thus promotes OER electrocatalysis through modulating the d-band center of Ni and reducing the adsorption energy of oxygenated intermediates on the surface of the catalyst. This work paves a promising avenue for the construction of desired high-valent metal OER catalysts by embedding redox inactive metals.

As one of the CO 2 capture and utilization technologies, Li-CO 2 batteries have attracted special interest in the application of carbon neutral. However, the design and fabrication of a low-cost highefficiency cathode catalyst for reversible Li 2 CO 3 formation and decomposition remains challenging. Here, guided by theoretical calculations, CO 2 was utilized to activate the catalytic activity of conventional nitrogen-doped graphene, in which pyridinic-N and pyrrolic-N have a high total content (72.65%) and have a high catalytic activity in both CO 2 reduction and evolution reactions, thus activating the reversible conversion of Li 2 CO 3 formation and decomposition. As a result, the designed cathode has a low voltage gap of 2.13 V at 1200 mA g −1 and long-life cycling stability with a small increase in the voltage gap of 0.12 V after 170 cycles at 500 mA g −1 . Our work suggests a way to design metal-free catalysts with high activity that can be used to activate the performance of Li-CO 2 batteries.

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Cu-Doped Co2P nanoparticles anchored on 2D heteroatom-doped ultrathin carbon exhibit excellent oxygen reduction reaction performance in flexible solid state zinc–air batteries.

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