In silico design of metal-free hydrophosphate catalysts for hydrogenation of CO2 to formate. Issue 5 (24th January 2022) - Wang, Honglei
Abstract : The metal-free catalysts composed of K3− n H n PO4 ( n = 0, 1, 2) and B(C6 F5− m H m )3 ( m = 0, 3, 5) are studied using DFT calculations, where this emerging Lewis pair catalyst is considered as a new class of candidate catalysts for reducing CO2 to formate. Abstract : CO2 reduction by H2 using metal-free catalysts is highly challenging. Frustrated Lewis pairs (FLPs) have been considered potential metal-free catalysts for this reaction. However, most FLPs are unstable, which limits their practical applications. In this study, a class of novel metal-free catalysts composed of K3− n H n PO4 ( n = 0, 1, 2) and B(C6 F5− m H m )3 ( m = 0, 3, 5) were prepared and identified as effective catalysts for CO2 hydrogenation to formate by density functional theory (DFT) calculations. The simulations show that the B–H bond formation is the rate-determining step (RDS). The acid/base strength and repulsive steric interactions affect the corresponding energy barrier. Therefore, the catalytic performance can be improved by choosing a suitable Lewis acid or base. Among these catalysts, the B(C6 H5 )3 –KH2 PO4 pair, with the lowest barrier height (26.3 kcal mol −1 ) in RDS, is suggested as a promising metal-free catalyst for CO2 hydrogenation. This study may provide strategies for designing new LP-based metal-free catalysts.