Work

High-performance single-atom M/TiO2 catalysts in the reverse water-gas shift reaction: A comprehensive experimental and theoretical investigation

Year: 2024

Type: article

Abstract: Single-atom catalysts (SACs) offer high efficiency and selectivity in chemical reactions but face challenges in converting CO 2 to CO via the reverse water gas shift (RWGS) reactions. This study addresses these challenges by anchoring three noble metals (Ir, Pd, and Ru) onto titania (TiO 2 ) and analyzing their performance. Comprehensive characterization techniques, including electron microscopy , confirmed the uniform dispersion of metal atoms on TiO 2 . Among the catalysts, Ir/TiO 2 exhibited the best results, achieving an 84 % CO 2 conversion rate and ∼98 % CO selectivity, surpassing Pd/TiO 2 and Ru/TiO 2 , which gained 56 % and 52 % conversion, respectively. In-situ gas transmission electron microscopy revealed the catalytic behavior of Ir/TiO 2 , showing Ir atom mobility and the formation of ∼1 nm nanoclusters . Density functional theory (DFT) and in-situ diffuse reflectance infrared spectroscopy (DRIFTs) further explained that the atomically dispersed Ir sites in Ir/TiO 2 follow a hydrogen-assisted mechanism, with the COOH* intermediate desorbing and dissociating into CO. These findings suggest SACs' potential to facilitate greener chemical processes and reduce greenhouse gas emissions .

Source: Journal of CO2 Utilization

DOI: 10.1016/j.jcou.2024.102988