General Descriptors for CO2-Assisted Selective C-H/C-C Bond Scission in Ethane.

Abstract

The selective C-H/C-C bond scission in CO2-assisted alkane activation represents an opportunity for simultaneously upgrading greenhouse gas CO2 and light alkanes for the synthesis of value-added syngas (CO and H2), olefins, aromatics, and oxygenates. Here, Pd bimetallic (PdMx)-derived catalysts were investigated for ethane-CO2 reactions by combining kinetic analysis, in situ characterization, and density functional theory calculations. Two types of catalyst structures were identified under the reaction conditions, with the PdCox alloy surface favoring ethoxy formation, a critical precursor for further C-C bond scission, and the reaction-induced InOx/Pd interface promoting C-H bond scission. Our results revealed a general strategy to capture the reaction-induced surface configurations and in turn control the selectivity in C-C/C-H bond scission over PdMx-derived catalysts, featuring the interplay of two general descriptors: formation energy of PdMx surfaces and their binding energy to oxygen. Our study provides insight into the rational design of selective catalysts for light alkane-CO2 reactions.