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

A density functional theory calculation has been carried out to investigate the mechanism of W(CO)6 and W2(CO)10 catalyzed water-gas-shift reaction (WGSR). The calculations indicate that the bimetallic catalyst (W2(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 (W2(CO)10) exhibits high catalytic activity towards WGSR due to the highest value of the calculated TOF (3.62 × 10−12 s−1, gas phase; 8.74 × 10−15 s−1, solvent phase), which is higher than the value of TOF (8.96 × 10−20 s−1, gas phase; 3.96 × 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.