Oxidation-Reduction Treatment Initiated In Situ Redispersion of the Supported Cu/Al₂O₃ Catalyst

Achieving a high dispersion of the supported catalyst is crucial for heterogeneous catalysts. However, such a goal is difficult to attain for copper-based catalysts with conventional preparation methods, especially at higher yet industrial-related loadings. In this study, we explore an oxidation-reduction treatment for in situ reconstruction of supported copper catalysts, promoting the redispersion of large Cu nanoparticles. Oxidation of the reduced Cu/Al₂O₃ catalyst turns large Cu nanoparticles into a hollow structure, which is attributed to the Kirkendall effect. The following reduction step produces reduced Cu nanoparticles with smaller diameters and an increased number of active sites. Such an oxidation-reduction treatment results in a remarkable two-fold increase in the activity of the Cu/Al₂O₃ catalyst, as compared to the untreated one, toward the methanol steam reforming reaction. Our findings present an innovative approach for the in situ improvement of the catalyst dispersion, holding great promise for heterogeneous catalytic applications.