Effect of Copper Particle Size on the Surface Structure and Catalytic Activity of Cu–CeO[sub.2] Nanocomposites Prepared by Mechanochemical Synthesis in the Preferential CO Oxidation in a H[sub.2]-Rich Stream

• Published in: Catalysts 2024-04, Vol.14 (4)
• Main Authors: Zhigalina, Olga M, Morozova, Olga S, Khmelenin, Dmitry N, Firsova, Alla A, Silchenkova, Olga V, Vorobieva, Galina A, Bukhtiyarov, Andrey V, Cherkovskiy, Evgeny N, Basu, Victoria G
• Format: Article
• Language: English
• Subjects: Analysis; Carbon monoxide; Carbonates; Catalysts; Chemical synthesis; Composite materials; Copper; Methods; Nanoparticles; Oxides; Properties; Structure
• ISSN: 2073-4344; 2073-4344
• DOI: 10.3390/catal14040222

An effect of Cu powder dispersion and morphology on the surface structure and the physical–chemical and catalytic properties of Cu–CeO[sub.2] catalysts prepared by mechanochemical synthesis was studied in the preferential CO oxidation in a H[sub.2] -rich stream (CO-PROX). Two catalysts, produced by 30 min ball-milling from CeO[sub.2] and 8 mass% of copper powders and with particle sizes of several tens (dendrite-like Cu) and 50–200 nm (spherical Cu obtained with levitation-jet method), respectively, were characterized by X-ray diffraction and electron microscopy methods, a temperature-programmed reduction with CO and H[sub.2] , and with Fourier-transform infrared spectroscopy. The catalyst synthesized from the “large-scale” dendrite-like Cu powder, whose surface consisted of CuxO (Cu[sup.+] ) agglomerates located directly on the surface of facetted CeO[sub.2] crystals with a CeO[sub.2] (111) and CeO[sub.2] (100) crystal planes exposition, was approximately two times less active at 120–160 °C than the catalyst synthesized from the fine Cu powder, whose surface consisted of CuxO (Cu[sup.2+] ) clusters of 4–6 nm in size located on the steps of facetted CeO[sub.2] nanocrystals. Although a large part of CO[sub.2] reacted with a ceria surface to give carbonate-like species, no blockage of CO-activating centers was observed due to the surface architecture. The surface structure formed by the use of highly dispersed Cu powder is found to be a key factor responsible for the catalytic activity.