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Flame-Made Surface-Substituted Copper–Ceria as an Excellent Reverse Water–Gas Shift Reaction Catalyst via Three Reaction Pathways

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide The limited mechanistic understanding and ambiguous structure–performance relationships have hindered the optimization of Cu-based catalysts for the reverse water–gas shift (rWGS) reaction. Here, we report a flame spray pyrolysis (FSP)-derived Cu–CeO 2 catalyst featuring highly dispersed, surface-substituted Cu + species (Cu y Ce 1– y O 2– x ) anchored on a defect-rich ceria matrix. This catalyst demonstrates excellent stability and outstanding rWGS activity at 600 °C, achieving a CO production rate of 8094 mmol/g cat. /h, surpassing the conventional Cu–CeO 2 catalyst and other reported rWGS catalysts. In situ spectroscopic analyses, supported by DFT calculations, reveal three parallel reaction pathways in which carboxylate- and formate-mediated routes proceed at distinct active sites. A clear structure–activity correlation is established across Cu +, Cu 0, and ceria defect sites in the FSP-derived catalysts. Notably, a previously underexplored carboxylate-mediated pathway, facilitated on the surface-substituted Cu + structure, is identified as the dominant route, featuring a significantly lower apparent activation energy (20–30 kJ/mol) compared to the classical formate pathway.

Source: Journal of the American Chemical Society

DOI: 10.1021/jacs.5c07701