Sulfur poisoned PtNi/C catalysts toward two-electron oxygen reduction reaction for acidic electrosynthesis of hydrogen peroxide

Abstract

Selective electrocatalysis of two-electron oxygen reduction reaction (2e– ORR) has been recognized as a sustainable and on-site process for hydrogen peroxide (H2O2) production. Great progress has been achieved for 2e– ORR in alkaline media. However, it is challenged by insufficient activity and selectivity of the catalysts in acidic electrolytes. Herein, we report sulfur-poisoned PtNi/C catalysts (PtNiSx/C) that could regulate ORR from the 4e– to 2e– pathway. The identified PtNiS0.6/C offers high activity in terms of onset potential of ∼0.69 V (vs. RHE) and ∼80% selectivity. The mass activity is also comparable and outperforms representative Pt-based precious and transition-metal-based catalysts. In addition, it is interestingly found that the Faradaic efficiency further increased to 95% during the long-term electrolysis test due to Ni atom surface migration. The electrochemical production of the H2O2 system was applied to the electro-Fenton process, which has realized the effective degradation of organic pollutants in wastewater. This work offers a strategy by sulfur poisoning PtNi/C catalyst to realize Pt-based 2e– ORR active catalysts to electrolysis of H2O2 in acidic media.