Electrochemical Synthesis of Hydrogen Peroxide in Neutral Media Using Oxygen Vacancy‐Engineered Gallium Oxyhydroxide Electrocatalyst

ABSTRACT The electrochemical two‐electron oxygen reduction reaction (2e − ORR) offers a promising strategy for sustainable H 2 O 2 production. However, developing efficient non‐noble metal‐based electrocatalysts for 2e − ORR in neutral media remains a significant challenge. Herein, we report the discovery of 2e − ORR catalysts based on the p ‐block metal gallium, in the form of gallium oxyhydroxide (GaOOH). This catalyst with oxygen vacancies (GaOOH‐ V o) achieved nearly 90% selectivity toward H 2 O 2 in neutral media, significantly higher than the 78% selectivity of GaOOH with minimal oxygen vacancies. Remarkably, when used in a gas diffusion electrode in a flow cell, GaOOH‐ V o maintains stable H 2 O 2 generation at 150 mA cm −2 for over 80 h, with an efficiency approaching 85%. Transient photovoltage spectroscopy, in situ Raman analysis, and detailed theoretical calculations reveal that the oxygen vacancies indeed mediate electron transfer, improve structural stability, and optimize reaction thermodynamics and kinetics for intermediates during 2e − ORR, thus resulting in impressive performance in neutral media. This study introduces innovative, high‐performance 2e − ORR catalysts derived from the p ‐block metal Ga, presenting new insights into the design and development of non‐noble metal‐based electrocatalysts for H 2 O 2 production.