Two birds with one stone: valence and substrate microenvironment engineering of Co-based catalysts for high-performance borohydride oxidation reaction
Tong Sun, Yiju Li, Tian Li, Youzhi Liu, Guisheng Qi, Weizhou Jiao, Shuang Zhao, Dongming Zhang
Abstract
Direct borohydride fuel cells (DBFCs) urgently need a deep understanding of the electronic structure–activity relationship of the transition metal-based electrode-catalyzed borohydride oxidation reaction (BOR) and an effective strategy to mitigate bubble effect. In this work, phosphorus (P) and oxygen (O) heteroatoms are utilized to regulate the low-valent Co content with high activity towards BOR in the catalytic center, while concurrently modifying the electronic structure of C to construct a microenvironment with strong adsorption for H atom . The interfacial synergistic effects between the catalytic center and the microenvironment optimize the H atom reaction pathway to mitigate the bubble effect and enhance fuel utilization. As a result, a record-high peak power density of 806 mW cm −2 is achieved with a CoP/O-C anode in the DBFCs. Macro high-speed camera reveals that the bubble density on the electrode surface is effectively mitigated. This work provides insight and feasible engineering strategies for studying valence-activity and microenvironment-selectivity relationships.