Synthesis of basalt fiber@Zn 1-x Mg x O core/shell nanostructures for selective photoreduction of CO 2 to CO

Abstract This study focused on the development of a catalyst for converting carbon dioxide, the main cause of global warming, into a beneficial energy source. Core@shell structured particles, BF@ZnO and BF@Zn 1-x Mg x O, are synthesized in order to selectively obtain CO gas from the photoreduction of CO 2 . A modified sol-gel process is used to synthesize the core@shell structures with a three-dimensional microstructure, which are subsequently characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDAX), ultraviolet (UV)–vis absorption, photoluminescence (PL), and photocurrent density analysis. The CO 2 adsorption abilities of the core@shell particles are estimated through CO 2 -temperature programmed desorption (TPD). The core@shell structured BF@Zn 1-x Mg x O particles including the Mg ingredient significantly increased the adsorption of CO 2 gas at the microfiber/nanoparticle interface. Both the BF@ZnO and BF@Zn 1-x Mg x O particles selectively reduce the carbon dioxide to carbon monoxide, with almost no other reduced products being observed. These results are attributed to the effective adsorption of CO 2 gas and inhibited recombination of the photogenerated electron–hole pairs. BF@Zn 0.75 Mg 0.25 O exhibited superior photocatalytic behavior and selectively produced 5.0 μmolg cat −1 L −1 of CO gas after 8 h of reaction.