Abstract
Modulation of water activation is crucial to water-involved chemical reactions in heterogeneous catalysis. Organic sulfur (COS and CS(2)) hydrolysis is such a typical reaction involving water (H(2)O) molecule as a reactant. However, limited by the strong O-H bond in H(2)O, satisfactory CS(2) hydrolysis performance is attained at high temperature above 310 °C, which is at the sacrifice of the Claus conversion, strongly hindering sulfur recovery efficiency improvement and pollution emissions control of the Claus process. Herein, we report a facile oxygen vacancy (V(O)) engineering on titanium-based perovskite to motivate H(2)O activation for enhanced COS and CS(2) hydrolysis at lower temperature. Increased amount of V(O) contributed to improved degree of H(2)O dissociation to generate more active -OH, due to lower energy barrier for H(2)O dissociation over surface rich in V(O), particularly V(O) clusters. Besides, low-coordinated Ti ions adjacent to V(O) were active sites for H(2)O activation. Consequently, complete conversion of COS and CS(2) was achieved over SrTiO(3) after H(2) reduction treatment at 225 °C, a favorable temperature for the Claus conversion, at which both satisfying COS and CS(2) hydrolysis performance and improved sulfur recovery efficiency can be obtained simultaneously. Additionally, the origin of enhanced hydrolysis activity from boosted H(2)O activation by V(O) was revealed via in-depth mechanism study. This provides more explicit direction for further design of efficacious catalysts for H(2)O-involved reactions.