Potential of Tandem Catalysts for Excellent H₂O₂ Electrosynthesis at Industrial-Relevant Current

Direct electrosynthesis of hydrogen peroxide (H 2 O 2 ) serves as an innovative and less-energy-demanding alternative to the conventional anthraquinone process. As the process involves active hydrogen (*H) production and hydrogenation of oxygen-containing intermediates, catalysts containing dual functional sites for *H and *OOH intermediate generation might boost the H 2 O 2 electrosynthesis activity. Here, we report a tandem catalyst with a uniform distribution of single-atom Al sites around Al 2 O 3 species, constituting the adjacent catalytic centers (Al 2 O 3 /Al 1 –O-C). The Al 2 O 3 /Al 1 –O-C catalysts exhibit high H 2 O 2 selectivity in alkaline conditions and achieve a yield rate of 39.4 mol g cat. –1 h –1 with a favorable stability of over 100 h in the flow cell. The direct output concentration of H 2 O 2 can reach 1659.2 mmol L –1 (5.61 wt %) at 400 mA cm –2 . The in situ measurements and simulated calculations reveal that the Al 2 O 3 sites catalyze the Volmer step in water decomposition to generate *H, which significantly promotes the *OOH generation from the reduction of *O 2 on single-atom Al sites, thus promoting H 2 O 2 electrosynthesis at high current densities. This tandem design enables industrially relevant H 2 O 2 electrosynthesis, demonstrating the potential for practical applications in the future.