B-Site Engineering in Ruddlesden-Popper Perovskites (A2BO4) for H2O2 Production with 4.85% of Solar-to-Chemical Efficiency

Abstract

The electrochemical synthesis of hydrogen peroxide (H2O2) via the oxygen reduction reaction (ORR) offers a promising alternative to the anthraquinone process, addressing environmental concerns without requiring expensive hydrogen. However, developing catalysts that selectively promote the two-electron ORR pathway while maintaining stability remains challenging. Here, we report Ruddlesden-Popper (RP) perovskite oxides as efficient catalysts for selective H2O2 production. Among the tested LaSrBO4 compositions (B = Ni, Co, Fe, Mn), LaSrNiO4 (LSN) showed the best two-electron ORR selectivity (similar to 87%) and activity. Integrated into a photovoltaic-electrochemical system, LSN achieved a solar-to-chemical conversion efficiency of 4.85%, producing a H2O2 production rate of 149.2 mu mol cm(-2) h(-1) with good stability over 50 h. Density functional theory calculations attributed this performance to favorable H2O2 formation and desorption kinetics at the Ni B-site. Overall, RP perovskites offer earth-abundant, efficient, and sustainable catalysts for electrochemical H2O2 generation, providing an alternative to carbon- or noble-metal-based systems.