DFT-based microkinetic studies on methanol synthesis from CO hydrogenation over InO and Zr-InO catalysts.

Density functional theory (DFT) calculations and microkinetic simulations were performed to study the structure-performance relationship of InO and Zr-doped InO catalysts for methanol synthesis, focusing on the InO(110) and Zr-doped InO(110) surfaces. These surfaces are expected to follow the oxygen vacancy-based mechanism the HCOO route for CO hydronation to methanol. Our DFT calcualtions show that the Zr-InO(110) surface is more favorable for CO adsorption than the InO(110) surface, and although the energy barriers are not lowered, most intermediates in the HCOO route are stablized with the introduction of the Zr dopant. Microkinetic simulations suggest that the CHOH formation rate is improved by ∼10 times and CHOH selectivity increased significantly from 10% on InO(110) to 100% on the Zr1-InO(110) catalyst model at 550 K. We find that the higher CHOH formation rate and CHOH selectivity on the Zr1-InO(110) surface than those on the InO(110) surface can be attributed to the slightly increased O formation energy and the stablization of the reaction intermediates, whereas the much lower CHOH formation rate on the Zr3-InO(110) surface is due to the much higher O formation energy and the over binding of the HO at the O site.