Enhancing catalytic hydrolysis activity of ZnNiAl hydrotalcite-like compounds-derived oxides using rare earth metals

Abstract

Efficient catalysts are highly desirable for the simultaneous removal of hydrogen cyanide (HCN) and carbonyl sulfide (COS) to meet the increasingly stringent emission standards and achieve cleaner production. In this study, ZnNiAl hydrotalcite-like compounds (HTLCs)-derived oxides doped with a series of rare earth metals, such as cerium (Ce), gadolinium (Gd), and yttrium (Y), were synthesized and used for the simultaneous hydrolysis of HCN and COS. The results demonstrated that the chemical state and electronic structure of ZiNiAl were changed by Ce doping because of the incorporation of Ce into the nickel oxide (NiO) network. Thus, abundant active species for the adsorption and dissociation of HCN and COS, including chemically adsorbed oxygen and strong basic sites, were produced by Ce doping. Meanwhile, the well-developed mesoporous structure provided accessibility to the active sites. As a result, Ce doping significantly enhanced the catalytic performance of ZnNiAl. Furthermore, the mechanisms of HCN and COS hydrolysis over Ce-ZnNiAl and their deactivation were proposed. This study provides a novel route for efficiently eliminating HCN and COS in diverse industrial processes.