CuO/ZnO catalysts in chitosan film for CO2 reduction

Abstract

In this work, ZnO of 1.1 and 10.2 nm sizes, respectively, were synthesized by irradiating femtosecond pulse laser in aqueous Zn ion precursor solutions at pH 5.5 and 10.2 in comparison with ZnO of 18.1 nm size prepared by hydrothermal procedure in an alkaline condition. The 12.8 nm CuO synthesized by precipitation method was physically mixed with ZnO, and the nanocomposites were embedded in chitosan (CS) film. Based on the catalytic activity of CuO/ZnO nanocomposite in CS film, the photocatalysis was performed for CO2 gas adsorbed on amine group in CS acting as a CO2 absorber. On the photocatalytic reaction under UV irradiation, the production of methanol was quantified using a chromogenic reagent, sodium nitroprusside. The highest catalytic activity (5642 μmol/g(catalyst)) for the CO2 conversion was achieved on CuO/ZnO/CS film, where ZnO was synthesized at pH 10.2 by femtosecond laser irradiation. The energy level alignment profile proposed the best hole transition from ZnO to CuO on CuO/ZnO/CS film in consistence with the best catalytic activity. Then the ecofriendly film-type system consisting of CS will be focused as promising biocompatible reactors because of facile production procedure and easy catalytic treatment.