Ru doping induced interface engineering in flower-liked CoMoO₄-RuO₂ boosts oxygen electrocatalysis for rechargeable...

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. RuO₂ based electrocatalysts are especially attractive due to the high catalytic activity of RuO₂. To reduce the usage of noble metal and improve the catalytic activity of catalyst, CoMoO₄-RuO₂ micro-flower was synthesized using a facile hydrothermal-calcination method in this work. CoMoO₄-RuO₂ 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 CoMoO₄-RuO₂ 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 RuO₂, which not only induces extra catalytic active sites, but also forms heterojunction with CoMoO₄ to optimize the electronic structure of CoMoO₄-RuO₂, thereby achieving a better equilibrium of absorption and desorption of intermediates. The work provides insights into designing RuO₂ based electrocatalysts for advanced electrocatalysis.