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A novel CoMoO 4 -RuO 2 heterogeneous catalyst with flower-liked morphology was developed as a highly efficient bifunctional oxygen electrocatalyst for Zn-air battery. [Display omitted] Constructing heterogeneous catalysts can significantly boost the electrocatalytic activity due to the improved intrinsic catalytic activity induced by tailored electronic structure and optimized chemisorption to the reaction intermediates. RuO 2 based electrocatalysts are especially attractive due to the high catalytic activity of RuO 2. To reduce the usage of noble metal and improve the catalytic activity of catalyst, CoMoO 4 -RuO 2 micro-flower was synthesized using a facile hydrothermal-calcination method in this work. CoMoO 4 -RuO 2 exhibits a low overpotential of 177 mV at 10 mA cm−2 for oxygen evolution reaction (OER) and a high half-wave potential of 0.858 V for oxygen reduction reaction (ORR). Moreover, the Zn-air battery assembled using CoMoO 4 -RuO 2 exhibit shows a high maximum discharge power density of 149 mW cm−2 and a large open circuit voltage of 1.38 V. The good performance can be attributed to the incorporation of RuO 2 , which not only induces extra catalytic active sites, but also forms heterojunction with CoMoO 4 to optimize the electronic structure of CoMoO 4 -RuO 2 , thereby achieving a better equilibrium of absorption and desorption of intermediates. The work provides insights into designing RuO 2 based electrocatalysts for advanced electrocatalysis. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction (OER) is an important half-reaction in rechargeable metal–air batteries and water splitting devices, and it suffers from slow kinetics due to the multiple step proton-electron coupled process. Therefore, the major challenge for the OER is to develop durable and low-cost electrocatalysts with high catalytic performance. Herein, a ternary metal CoNiFe subacetate nano prism (CoNiFe NP) was synthesized by a one-step hydrothermal method, with the aim of accelerating the water dissociation and improving the reaction rate using the synergy of the ternary metal. The results show that the electrocatalytic performance of the ternary metal CoNiFe layered double hydroxide is significantly improved compared with the binary metal and single metal catalysts. In particular, the overpotential of the prepared CoNiFe NP for the OER at 10 mA cm−2 is as low as 292 mV, and the Tafel slope is 75.6 mV dec−1. This work provides a new platform for the design of medium-entropy electrocatalysts using the interaction of polymetallic components. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hollow CoVO x /Ag heterojunction was synthesized for OER. • The interaction of CoVO x and Ag nanoparticles regulated the electronic structure. • The extrinsic catalytic activity of CoVO x /Ag is enhanced due to the hollow structure. • The OER overpotential for CoVO x /Ag-5 at 10 mA cm−2 is only 247 mV. • The catalyst can enable full water splitting with 100% Faraday efficiency. Developing high-active and inexpensive electrocatalysts for oxygen evolution reaction (OER) is very important in the field of water splitting. The catalytic performance of electrocatalysts can be significantly improved by optimizing the electronic structure and designing suitable nanostructure. In this work, we represent the synthesis of hollow CoVO x /Ag-5 for OER. Due to the interaction of CoVO x and Ag nanoparticles, the electronic structure is optimized to improve the intrinsic catalytic activity. Additionally, the extrinsic catalytic activity of CoVO x /Ag is enhanced by the abundant active sites from the hollow structure. As a result, the CoVO x /Ag-5 demonstrates significantly enhanced OER catalytic activity with a low overpotential of 247 mV at 10 mA cm−2. In addition, it also exhibits excellent durability, without obvious attenuation in performance after continuous operation for 60 h. Furthermore, the catalyst can enable full water splitting with appropriate 100 % Faraday efficiency, demonstrating its practical application. [ABSTRACT FROM AUTHOR]