Lanthanum-bismuth mixed oxide catalyst with improved activity for carbonyl sulfide hydrolysis

The presence of carbonyl sulfide (COS) in industrial tail gas poses considerable risks to human health and ecosystems. Catalytic hydrolysis is efficient in COS removal, yet developing high-performance catalysts at low temperatures remains challenging. In this work, we designed novel nanorod-like lanthanum-bismuth (La-Bi) mixed oxides for the catalytic hydrolysis of COS. The COS hydrolysis activity of the Bi-doped catalyst was significantly improved as compared to the bare La oxide. The catalysts with various La/Bi ratios were thoroughly analyzed by microscopic and spectroscopic techniques to elucidate their structural and chemical properties. The results indicated that the Bi doping into the La oxide enhanced the basicity and electron transfer of the catalyst, leading to improved hydrolysis activity. A reaction pathway for the COS catalytic hydrolysis on La-Bi mixed oxide was proposed, in which COS adsorption was significantly strengthened due to enhanced basicity, and thereby the formation of intermediates such as HCO3  and HSCO2 -was facilitated. In addition, the La-Bi mixed oxide catalyst demonstrated excellent sulfur tolerance and stability in long-term testing using simulated indus-trial gas.