Bimetallic MOF@CdS nanorod composite for highly efficient piezo-photocatalytic CO2 methanation under visible light

Abstract

CO2 methanation is leading progress in both dwindling the emitted greenhouse gas and taking advantage of CO2 conversion to a worthwhile fuel. Various types of catalysts have gained researchers' attention. On the other hand, those catalysts chiefly suffer from being uneconomical, owning laborious processes, and having low efficiency. Particularly in the photocatalytic process, electron-hole recombination, charge separation efficiency, and the photocorrosion are the most remarkable obstacles in the path of gaining high efficiency. To conquer the aforementioned hindrances, Cu/Zr-MOF@CdS had been designed in order to not only do elevate CH4 selectivity but also increase CO2 conversion by altering the electron transfer mechanism. Doping Cu in Zr-MOF structure restrains C-C coupling and ameliorates the viability of protonation of *CO to *HCO during methane production. CdS and Zr-MOF both grant piezoelectricity trait to the catalyst in a way that by merging it with the photocatalytic process the mechanism of process converted from type (II) scheme to Z-scheme, culminating in thwarting recombination and increase of charge separation efficiency. The photocatalytic process achieved 23.6 μmol. g−1. h−1 CH4 reaction rate and 80 % CO2 conversion, hereafter applying the piezo-photocatalytic process, these two factors reached 52.2 μmol. g−1. h−1 and 99 %, respectively. This work unveils the viable reaction routes along with their several quotas in piezo-photocatalytic CO2 methanation process by scrutinizing the intricate mechanisms via in-situ analyses.