Mechanochemical Synthesis as an Alternative Effective Techniquefor the Preparation of the Composite Catalysts
Mechanochemical synthesis in a ball mill was applied for the nanocomposite Cu(CuO)–CeO<sub>2</sub> catalyst preparation from CeO<sub>2 </sub>and following dopants: Cu metal and copper oxides of different morphology and composition (CuO and CuO containing 4 or 16.5 mass. % of Cu<sub>2</sub>O). The materials obtained were examined with the use of X-ray phase analysis, scanning electron microscopy, temperature-programmed reduction in CO, H<sub>2</sub>, C<sub>2</sub>H<sub>6</sub> (TPR-СО, TPR-Н<sub>2,</sub> and TPR-С<sub>2</sub>Н<sub>6</sub>), and tested as catalysts in reactions of selective CO oxidation in H<sub>2</sub> excess (CO-PROX) and total C<sub>2</sub>H<sub>6</sub> oxidation. New forms of oxygen with high low-temperature reactivity towards CO, H<sub>2,</sub> and C<sub>2</sub>H<sub>6</sub> were found in the samples synthesized by TPR. It was shown that CO conversion was slightly affected by the dopant nature in the dopant-CeO<sub>2</sub> mixture. Contrary, C<sub>2</sub>H<sub>6</sub> conversion at low temperatures depends on dopant composition. The highest C<sub>2</sub>H<sub>6 </sub>conversion at 400°С (91.4%) was observed on Cu–CeO<sub>2</sub>. The lowest one (54.2%) was observed on CuO–CeO<sub>2</sub>. As was demonstrated, mechanochemical synthesis is a universal technique to produce copper oxide –ceria catalysts.