CeO2, V2O5 and CeVO4 were synthesised as bulk oxides, or deposited over activated carbon, characterized by XRD, HRTEM, CO2-TPO, C3H8-TPR, DRIFTS and Raman techniques and tested in propane oxidative dehydrogenation using CO2. Complete oxidation of propane to CO and CO2 is favoured by lattice oxygen of CeO2. The temperature programmed experiments show the ~ 4 nm AC supported CeO2 crystallites become more susceptible to reduction by propane, but less prone to re-oxidation with CO2 compared to bulk CeO2. Catalytic activity of CeVO4/AC catalysts requires a 1–2 nm amorphous CeVO4 layer. During reaction, the amorphous CeVO4 layer crystallises and several atomic layers of carbon cover the CeVO4 surface, resulting in deactivation. During reaction, V2O5 is irreversibly reduced to V2O3. The lattice oxygen in bulk V2O5 favours catalytic activity and propene selectivity. Bulk V2O3 promotes only propane cracking with no propene selectivity. In VOx/AC materials, vanadium carbide is the catalytically active phase. Propane dehydrogenation over VC proceeds via chemisorbed oxygen species originating from the dissociated CO2.

中文翻译：

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CO2 在本体和活性炭负载的铈和钒基催化剂上丙烷氧化脱氢过程中的作用

CeO2、V2O5 和 CeVO4 合成为块状氧化物，或沉积在活性炭上，通过 XRD、HRTEM、CO2-TPO、C3H8-TPR、DRIFTS 和拉曼技术进行表征，并在使用 CO2 的丙烷氧化脱氢中进行测试。CeO2 的晶格氧有利于丙烷完全氧化成 CO 和 CO2。程序升温实验表明，约 4 nm AC 支持的 CeO2 微晶变得更容易被丙烷还原，但与本体 CeO2 相比更不容易被 CO2 再氧化。CeVO4/AC 催化剂的催化活性需要 1-2 nm 的非晶 CeVO4 层。在反应过程中，无定形 CeVO4 层结晶，几个碳原子层覆盖 CeVO4 表面，导致失活。在反应过程中，V2O5 不可逆地还原为 V2O3。本体 V2O5 中的晶格氧有利于催化活性和丙烯选择性。本体 V2O3 仅促进丙烷裂化，而没有丙烯选择性。在 VOx/AC 材料中，碳化钒是催化活性相。VC 上的丙烷脱氢通过源自解离的 CO2 的化学吸附氧物质进行。