Fabrication of a Photocatalyst with Biomass Waste for H₂O₂ Synthesis

Synthesis of the indispensable H₂O₂ in pure water remains a challenge for current methods, which often require organic solvents (anthraquinone method), sacrificial agents of alcohols (traditional photocatalysis), or electrolyte of salts (electrochemical synthesis). Here, various biomass (glucose, sucrose, starch, cellulose, and paperboard) was converted to hydrothermal carbonaceous carbon (HTCC) photocatalysts for H₂O₂ synthesis in pure water. The apparent quantum yield and synthesis rate could reach 18.2% (at 420 nm) and 1.16 mmol g_cat^–1 h^–1, respectively. Importantly, HTCC can be prepared with biomass waste such as paperboard. Mechanism study indicates that H₂O₂ production on HTCC is dominantly via a two-step oxygen reduction reaction with superoxide anions as an intermediate. Through theoretical calculation, it was found that the polyfuran structure of HTCC is favorable for adsorption and activation of oxygen and exhibits superior electron transfer property. These are the key steps for oxygen reduction and the subsequent H₂O₂ production. This work provides insights into activation of oxygen on the emerging HTCC photocatalyst and highlights its appealing application for H₂O₂ synthesis in pure water.