A solvent-free method to rapidly synthesize CuO-CeO2 catalysts to enhance their CO preferential oxidation: Effects of Cu loading and calcination temperature

Abstract

A facile and solvent-free route has been developed to rapidly synthesize CuO-CeO2 catalysts within 30min. The effect of calcination temperature on catalytic performances is more significant than Cu loading, and the optimal calcination temperature and Cu loading are 700°C and 7.5wt.%, respectively. The optimal catalyst 7.5CuCe-SF-700 exhibits the highest CO conversion and the corresponding temperature window for full CO conversion is as wide as 50°C. According to the characterization results of XRD, N2 adsorption-desorption, H2-TPR, TEM, HR-TEM, STEM, EDS, Raman and XPS, it can be concluded that the high-performances of CuO-CeO2 catalyst should be attributed to synergistic effects of high dispersion Cu species and CeO2, and the presence of more reduced copper species as the active site in the catalyst. 7.5CuCe-SF-700 exhibits excellent stability for CO-PROX during the 200 time-on-stream test under actual reaction conditions (with 15% CO2 and 10% H2O). In addition, surfactant template, urea gelation/co-precipitation and sol-gel methods were used to synthesize CuO-CeO2 catalysts so as to compare them with 7.5CuCe-SF-700, and the results exhibit not only 7.5CuCe-SF-700 is superior to the former three catalysts but also our synthesis route is more simple, controllable, solvent-free, time-saving and energy-saving.