On-site electrochemical production of hydrogen peroxide (H2O2), an oxidant and disinfectant with a growing demand, could be realized through the selective two-electron oxygen reduction reaction (2e– ORR), but the widespread adoption of this method depends on robust and efficient electrocatalysts. Current catalysts have been limited by cost or toxicity and lack well-defined structures that can facilitate systematic tuning of activity and selectivity. Here, we demonstrate the synthesis of a series of CuCo2–xNixS4 (0 ≤ x ≤ 1.2) thiospinel catalysts that are highly selective for 2e- ORR (&gt;60%) with activity that can be systematically increased. Furthermore, we show new directions of metal selenide catalysts that can enhance stability for 2e- ORR catalysts. Bulk electrolysis experiments reveal the trends in the accumulated concentrations of H2O2 and metal leaching behaviors on these catalysts, some of which lead to a built-in electro-Fenton process to generate hydroxyl radicals. Using various structural techniques including synchrotron X-ray spectroscopy, we study the post-electrolysis structures of these catalysts and the fine changes to their structures due to structural tuning in order to establish general strategies for designing active, selective, and robust 2e- ORR catalysts.

Structural design of transition metal sulfide and selenide catalysts towards enhanced electrosynthesis of hydrogen peroxide

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.