Atomically Dispersed Co/Mo Sites Anchored on Mesoporous Carbon Hollow Spheres for Highly Selective Oxygen Reduction to Hydrogen Peroxide in Acidic Media
Min Yang, Weihao Song, Chengjin Chen, Xue Yang, Zhongbin Zhuang, Huabin Zhang, Feng Wang, Le Yu
Abstract
Abstract Two‐electron oxygen reduction reaction (2e − ORR) in acidic media is a promising route for the decentralized and on‐site hydrogen peroxide (H 2 O 2 ) generation. Nevertheless, strong interaction between active sites and * OOH intermediates usually induces the O─O bond cleavage to convert 2e − pathway into the sluggish 4e − ORR. Therefore, it is highly necessary to optimize the electronic structure of 2e − ORR electrocatalysts for the regulation of adsorption energy. Herein, we propose the utilization of atomically dispersed Co/Mo sites anchored on mesoporous carbon hollow spheres (Co/Mo‐MCHS) via a template‐engaged strategy for highly selective ORR to H 2 O 2 in acid. Benefitting from the electron‐donating effect of Mo atoms, an enriched electron density around the Co center for Co/Mo‐MCHS is observed, resulting in optimal adsorption of the key * OOH intermediates to approach the apex of 2e − ORR volcano plot. Moreover, the introduction of Mo species simultaneously suppresses the electroreduction of as‐obtained H 2 O 2 on Co sites. As a consequence, Co/Mo‐MCHS delivers a high H 2 O 2 selectivity of 90–95% in acid. The flow cell based on the Co/Mo‐MCHS catalyst achieves a remarkable H 2 O 2 yield of 2102 mg for 150 h. Moreover, this strategy can be extended to other early transition metal elements with similar electronic modifier effects.