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

Abstract

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 ·O2− group formation, resulting in better AR1 decolorization efficiency. The optimal AR1 decolorization efficiency and hydrogen production ability, respectively, reached 99.4% and 1127 μmol/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.