Avoiding Sabatier’s conflict in bifunctional heterogeneous catalysts for the WGS reaction

Abstract

A new strategy for designing efficient bifunctional heterogeneous catalysts for the water-gas-shift (WGS) reaction (CO + H2O → CO2 + H2) is presented. We avoid conflicting tasks that require ∗OH or ∗O from dissociated water to adsorb on and then desorb from the substrate of a catalyst. Instead, the CO on metal directly obtains OH from water that is connected by weak hydrogen bonds to the substrate. The task of the substrate is to efficiently channel ∗H on its surface and release them as H2 gas. Experimental and theoretical results show that bifunctional catalysts with weakly reactive substrates have significantly higher CO conversion rates compared with highly reactive substrates that follow either the LH-associative or LH-redox process.