Hydroxylated Boron Crystal Domain-Modulated Heterostructure Carbon Catalysts for Efficient Hydrogen Peroxide Generation

Abstract

Metal-free heterostructure carbon catalysts are promising alternatives to metal-based catalysts for electrochemical hydrogen peroxide (H₂O₂) synthesis via the two-electron oxygen reduction reaction (2e^– ORR). However, one appropriate nanocrystal type is being sought to resolve a concern at industrial-level current densities. Herein, nano boron crystal domains (B_n) overcame the stability limitations of traditional carbon-based electrocatalysts for sustainable H₂O₂ production and industrial application. A B_n–C catalyst offered multiple active sites, while the nano B_n imparted an O₂ enrichment effect enhancing mass transfer during ORR electrocatalysis. The B_n–C exhibited a very high mass activity (11.6/10.7 mol g_cat^–1 h^–1) in alkaline/neutral electrolytes and showed negligible loss in activity and Faradaic efficiency (over 90%) during 100 h continuous electrolysis at high current density (>300 mA cm^–2). Density functional theory and in situ Raman experiments demonstrated that the –OH groups connecting nano B_n provided an inductive effect on B atoms in the carbon matrix, alleviating a binding strength that is too strong with *OOH intermediate.