Tuning Ni3+ Content in Ni3S2 to Boost Hydrogen Peroxide Production for Electrochemical Synthesis

Hydrogen peroxide is a green oxidizing chemical with wide applications in industry. Its production heavily relies on the industrial anthraquinone process, which involves a large number of organic pollutants, challenging green and sustainable development. The recently developed pulsed electrochemical approach holds great potential for the green synthesis of hydrogen peroxide, but it is limited by the absence of highly efficient catalysts. Here, we report a strategy to improve the performance of Ni3S2 catalyst by tuning the content of Ni3+ species. The Ni3S2 catalyst exhibits good performance in oxygen evolution and oxygen reduction processes at the same time, leading to the formation of hydrogen peroxide. The enrichment of Ni3+ ensures the adsorption of reaction intermediates *O, *OH, and *OOH and promotes electron transfer during the reaction, thus facilitating hydrogen peroxide generation. By tuning the Ni3+ ratio in the Ni3S2 catalyst, the productivity of hydrogen peroxide was enhanced. The prepared hydrogen peroxide was used for propylene oxidation, resulting in pH-dependent products. This study highlights the significance of the design and rational synthesis of electrochemical catalysts for synthesizing hydrogen peroxide, which may be used for the electrochemical synthesis of chemicals.