Acceleration of acid red 1 dye decolorization efficiency by adding methanol with simultaneous hydrogen production

A promising and efficient pathway for simultaneous photocatalytic decolorization of acid red 1 (AR1) dye and hydrogen production was developed in this study. The results demonstrated that the AR1 decolorization efficiency was accelerated by adding only 15 v/v% methanol, which was attributable to the decreased charge recombination rate caused by methanol molecules. The decreased charge recombination rate led to increased .OH and .O-2(-) group formation, resulting in better AR1 decolorization efficiency. The optimal AR1 decolorization efficiency and hydrogen production ability, respectively, reached 99.4% and 1127 mu mol/h/g when the AR1 concentration and methanol concentration were, respectively, controlled to 6 mg/L and 15 v/v%. The enhanced AR1 decolorization efficiency was ascribed to the lower rate of electron-hole recombination. Due to the lower electron-hole recombination rate, more electron-hole pairs effectively produced superoxide radicals and hydroxyl radicals, which resulted in substantially enhanced AR1 decolorization efficiency.