ZnO晶面对纳米Au催化CO氧化性能的影响

采用水热合成法制备了无择优暴露晶面的盘状ZnO（ZnO-D）和优先暴露（100）非极性面的片花状ZnO（ZnO-F）；通过沉积-沉淀法将Au纳米颗粒负载于所制备的ZnO载体表面；采用ICP、XRD、SEM、TEM、XPS和BET对合成的催化剂进行表征；最后，以CO氧化为探针反应研究载体晶面对金纳米颗粒催化性能的影响。结果表明，ZnO形貌对Au颗粒粒径影响甚微，但Au物种的电子价态表现出显著的载体形貌依赖性。以盘状和片花状ZnO为载体所获得的金催化剂的Au^δ+物种的原子分数分别为34.8%和67.4%，说明Au颗粒与片花状ZnO间具有更强的金属-载体相互作用。Au/ZnO-F催化剂的CO氧化活性明显优于Au/ZnO-D，归因于Au/ZnO-F具有较高的O₂吸附活化能力。本文通过调控载体形貌/晶面进而调变金属-载体间相互作用及Au物种的化学态的方法提高了Au催化性能。

Crystal plane effect of ZnO on the catalytic properties of Au nanostructure for CO oxidation

To investigate the crystal plane effect of the support on the catalytic performance of Au nanoparticles, we synthesized two ZnO nanomaterials with different morphologies by a hydrothermal method, i.e. disc-like ZnO (ZnO-D) without any dominant facets and nanosheet-assembled flower-like ZnO (ZnO-F) exposing preferentially (100) nonpolar planes. Then, two different Au/ZnO catalysts were obtained via deposition-precipitation method with the as-prepared ZnO as support, characterized by ICP, XRD, SEM, TEM, XPS and BET, and evaluated with the CO oxidation reaction. The characterization results demonstrated that the Au nanoparticles deposited on ZnO with different shapes showed similar average size but different redox states. The percentage of Au^δ+ species in Au/ZnO-D and Au/ZnO-F were 34.8% and 67.4%, respectively, indicating stronger interaction between Au species and the flower-like ZnO. The Au/ZnO-F catalyst exhibited much higher activity than Au/ZnO-D, because of its excellent capability in adsorption and activation of O₂ molecular. This finding shows that the catalytic performance of Au-based catalysts can be enhanced by altering the interaction between Au and the support with specific crystal facets.