B-Site Engineering in Ruddlesden–Popper Perovskites (A 2 BO 4 ) for H 2 O 2 Production with 4.85% of Solar-to-Chemical Efficiency

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 (∼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 μmol 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.