Coproduction of hydrogen peroxide and formic acid as potential hydrogen-carrier through photocatalytic reformation of sacrificial chemical

This study explores the challenges to photo-reforming sacrificial chemicals into beneficial by-products while improving photocatalytic activity in H₂O₂ production by addressing several issues. The resorcinol-formaldehyde/graphitic carbon nitride composite (RF_0.2GCN) with nanosheet-like RF morphology achieved a higher degree of surface-to-surface contact through -C-NH-CH₂- and -NH-CH-OH than the nanosphere (RF_0.8GCN). The RF_0.2GCN produced H₂O₂ at 325.2 µg g⁻¹ s⁻¹ in the presence of oxalic acid (OA) at pH 2.1 with apparent quantum yield (AQY) of 12.7 %. The conduction band position potential was +0.54 V_NHE, which is thermodynamically unfavorable for H⁺/H₂ (E°: 0.00 V_NHE) and O₂/·O₂⁻ (E°: −0.046 V_NHE) reaction and also inhibits the decomposition of H₂O₂ (H₂O₂/·OH, E°: +0.39 V_NHE). Furthermore, the decomposition of OA formed formic acid (FA) at 82 % selectivity and concurrent CO₂·⁻ formation could promote electron density in the conduction band via its electron-donating ability·H₂O₂ was purified by isolating FA using anion exchange resin, and FA was recovered by desorption from the resin using HCl (pH 3).