Charge transfer and electron jumping for highly tribocatalytic H2O2 generation of silicon powder materials

Abstract

Hydrogen peroxide (H2O2) is a critical green chemical pivotal to numerous industries, including healthcare, energy, chemical synthesis, and environmental remediation. The production of H2O2 directly from earth-abundant water, especially under ambient conditions without relying on gaseous oxygen, represents a highly sustainable and potentially economical route. Triboelectric effects enable the harvesting of friction, a ubiquitous clean energy source, for conversion into electrical energy. In this study, the efficient tribocatalytic production of H2O2 is demonstrated at the friction interface between silicon (Si) powder and a rotating polytetrafluoroethylene (PTFE) disk, utilizing a 10% ethanol solution as the reaction medium under ambient air. The narrow bandgap of Si (1.12 eV) facilitates charge excitation under low-frequency mechanical stirring, resulting in sustained H2O2 generation under mild conditions. A maximum H2O2 concentration of ~174.6 µmol·L⁻¹ is achieved. Quenching experiments reveal that the tribocatalytic mechanism predominantly involves hydroxyl radicals ("∙OH" ), superoxide radicals ("∙" "O" _"2" ^"-" ), and electrons ("e" ^"-" ) as the principal active intermediates. Subsequently, these free radicals combine to form H2O2 "(2 ∙OH →" 〖" H" 〗_"2" "O" _"2" ",∙" "O" _"2" ^"-" " +" 〖" e" 〗^"-" " + 2" "H" ^"+" " → 2" "H" _"2" "O" _"2" ). This finding demonstrates that H2O2 can be efficiently synthesized through a tribocatalysis pathway under ambient temperature and pressure by applying mechanical force at the interface between Si powder and a 10% ethanol solution in the presence of air. This work provides a promising strategy for the green and efficient generation of H2O2 via tribocatalysis.