Cu-ZnO Heterojunction Catalytic SF6/H2 Gas Conversion Mechanism and Reaction Network Construction

Abstract

How to treat waste sulfur hexafluoride (SF6) in an environmentally friendly way to alleviate the greenhouse effect caused by it is a global concern. In this article, a catalytic reaction model of the gas–solid reaction interface formed by the main active sites of SF6/H2 and Cu-ZnO heterojunctions was constructed. Subsequently, the thermodynamic properties of SF6 in the process of adsorption, dissociation, and defluorination occurring on the surface of the Cu-ZnO catalyst under the H2 atmosphere were investigated. A defluorination and hydrogenation reaction network of 22 reactions was constructed. To better fit the actual situation in engineering application, the participation of trace water and oxygen was considered. The total reaction heat for the conversion of SF6 to the target reduction product H2S catalyzed by the Cu-ZnO heterojunction is −12.90 eV. Compared to the primary decomposition on the Cu(111) surface, the Cu-ZnO interface reduces the reaction energy of complete defluorination by 297.04%, showing an outstanding catalytic conversion activity. This indicates that ZnO not only plays the reductant carrier but also participates in the catalytic process. This article offers a new method for managing the greenhouse effect problem caused by SF6, proposes a set of catalytic pathways, and analyzes the catalytic mechanism of Cu-ZnO.