Theoretical Study of the Water-Gas Shift Reaction Catalyzed by Tungsten Carbonyls

摘要

A density functional theory calculation has been carried out to investigate the mechanism of W(CO)(6) and W-2(CO)(10) catalyzed water-gas-shift reaction (WGSR). The calculations indicate that the bimetallic catalyst (W-2(CO)(10)) would be likely to be more highly active than the mononuclear metal-based catalyst (W(CO)(6)) due to the possibility of metal-metal cooperativity in reducing the barriers for the WGSR. The energetic span model is a tool to compute catalytic turnover frequencies (TOFs) which is the traditional measure of the efficiency of a catalyst. The one with the highest efficiency usually gives the highest TOF. The bimetallic catalyst (W-2(CO)(10)) exhibits high catalytic activity towards WGSR due to the highest value of the calculated TOF (3.62 x 10(-12) s(-1), gas phase; 8.74 x 10(-15) s(-1), solvent phase()), which is higher than the value of TOF (8.96 x 10(-20) s(-1), gas phase; 3.96 x 10(-19) s(-1), solvent phase) proposed by Kuriakose et al. (Inorg Chem 51:377-385, 2012). Our results will be important for designing a better catalyst for the industrially important reaction.