Work

Tailoring Cu–CeO₂ catalysts to elucidate the morphology–activity relationship in low-temperature water–gas shift reaction

Year: 2025

Type: article

Abstract: The low-temperature water-gas shift (WGS) reaction confronts critical challenges of sluggish kinetics, inadequate H 2 yield and CO conversion, necessitating the development of high-activity catalysts to effective clean energy production with reduced energy consumption. In this study, we systematically investigate the relationship between the physicochemical properties of Cu-based catalysts supported on CeO 2 with tailored morphologies (nanorods, nanospheres, and nanocubes) and catalytic performance. Cu-CeO 2 (R) achieves 52.3 % CO conversion and 79.88 mL/gH 2 O H 2 production at 370 °C—nearly twice those of Cu-CeO 2 (P) under identical conditions—with an apparent activation energy of 55.25 kJ·mol −1 . This outstanding performance stems from proper oxygen vacancy concentration (OVC, 2.23 × 10 21 cm −3 ) and ordered Cu + -[O v ] Ce 3+ interfacial sites induced by strong metal-support interaction (SMSI) within Ce 1-x Cu x O 2 solid solutions. In contrast, Cu-CeO 2 (S) and Cu-CeO 2 (C) display relatively lower maximum CO conversions (45.97 % at 410 °C and 43.7 % at 370 °C, respectively), due to excessive defect oxygen (34.41 % and 44.89 %) that strongly adsorbs reaction intermediates, postponing the WGS rate by 15–20 %. In-situ spectroscopy reveals that CeO 2 morphology modulates oxygen vacancy (O v ) distribution and Cu Ce interfacial structures, giving rise to distinct adsorption states and binding strengths of CO/CO 2 on Cu/CuO x nanoclusters with varied valence states and dispersions. Cu-CeO 2 (S) and Cu-CeO 2 (C) exhibit complex carbonation pathways, featuring dynamic evolution of intermediates from monodentate to bidentate to polymeric carbonates, attributed to surface site diversity and cross-interactions of Cu sites. This work elucidates the morphology-activity relationship of Cu-CeO 2 catalysts, providing insights for the rational design of highly active low-temperature WGS catalysts.

Source: Journal of Colloid and Interface Science

DOI: 10.1016/j.jcis.2025.139458