ZnO-incorporated ZSM-5 for photocatalytic CO₂ reduction into solar fuels under UV/Visible light

Direct conversion of CO₂ into chemical compounds has become a prospective pathway to transform CO₂ into valuable chemical compounds. Introduction of porous materials with high CO₂ uptake into the photocatalytic system can enrich the CO₂ absorption on the surface of the photocatalyst for catalytic conversion. In this regard, another feasible strategy can be accomplished via combining commercial photocatalyst material into porous supporting materials. The present study investigated a series of ZnO-incorporated ZSM-5 catalysts to produce solar fuels under UV/Visible light irradiation. ZnO/ZSM-5 was synthesized using wet-impregnation method using Zn(CH₃COO)₂ as reagent and followed by calcination. Various characterizations were also conducted to study the morphology, structure, absorbance, and physiochemical properties of the photocatalyst. SEM-EDX images showed that ZnO was successfully incorporated into ZSM-5 surfaces with particle size around 50 nm. Optical properties of the ZnO/ZSM-5 correspond to 3.00 eV, showing a significant decrease of the bandgap value than pure ZnO, which corresponds to 3.10 eV. The solar fuels generation for H₂ and hydrocarbons, such as HCOH, CH₃OH, and HCOOH evolution reaction were evaluated in the photocatalytic CO₂ reduction under UV/Visible light irradiation. Incorporating the ZnO heterostructure in the ZSM-5 surface resulted in more efficient charge transfer, improved light absorption, and more active sites available for the CO₂ adsorption and photocatalytic reactions. The ZnO/ZSM-5 composite exhibited a remarkably high H₂ and CH₃OH evolution after 2 h of irradiation. A mechanism of the photocatalytic reaction was proposed.