Catalytic hydrolysis of carbonyl sulphide and carbon disulphide over Fe(2)O(3) cluster: Competitive adsorption and reaction mechanism

The competitive adsorption and reaction mechanism for the catalytic hydrolysis of carbonyl sulphide (COS) and carbon disulphide (CS(2)) over Fe(2)O(3) cluster was investigated. Compared with experimental results, the theoretical study was used to further investigate the competitive adsorption and effect of H(2)S in the hydrolysis reaction of COS and CS(2). Experimental results showed that Fe(2)O(3) cluster enhanced the catalytic hydrolysis effect. Meanwhile, H(2)S was not conducive to the hydrolysis of COS and CS(2). Theoretical calculations indicated that the order of competitive adsorption on Fe(2)O(3) is as follows: H(2)O (strong) >CS(2) (medium) >COS (weak). In the hydrolysis process, the C=S bond cleavage occurs easier than C=O bond cleavage. The hydrolysis reaction is initiated via the migration of an H-atom, which triggers C=S bond cleavage and S–H bond formation. Additionally, we find the first step of CS(2) hydrolysis to be rate limiting. The presence of H(2)S increases the reaction energy barrier, which is not favourable for COS hydrolysis. Fe(2)O(3) can greatly decrease the maximum energy barrier, which decreases the minimum energy required for hydrolysis, making it relatively facile to occur. In general, the theoretical results were consistent with experimental results, which proved that the theoretical study was reliable.