氧化锌形貌效应对光催化甲烷有氧偶联的影响

The morphology effect of zinc oxide in photocatalytic oxidative coupling of methane

采用水热法并通过改变Zn前驱体、表面活性剂和水热温度等条件制备不同形貌的六方纤锌矿ZnO晶体,Au纳米颗粒作为助催化剂被负载在所合成的不同形貌的ZnO上。采用了FESEM、XRD、ICP方法对制备的光催化剂进行表征,并考察了其在光催化甲烷有氧偶联中的反应活性与反应选择性。结果表明,约30 nm的尖型ZnO纳米颗粒表现出显著提高的光催化甲烷转化活性;花型堆积的ZnO纳米片的催化活性略低于商业化的无规则ZnO纳米颗粒,但花型堆积的ZnO纳米片对C^(2+)高级烷烃的反应选择性更高;六棱柱形ZnO纳米棒则表现出极低的反应活性,但仍表现出相似的C^(2+)反应选择性。合适的主催化剂形貌与晶面调控对提高和改善光催化甲烷转化的性能具有重要且关键的影响。

Hexagonal wurtzite ZnO crystals with different morphologies were prepared by hydrothermal method in different conditions of Zn precursor,surfactant and hydrothermal temperature.Au nanoparticles as cocatalysts were successfully loaded on the synthesized ZnO and the catalysts were characterized by FESEM,XRD and ICP.The activity and selectivity in photocatalytic OCM were investigated.The results show that the about 30 nm pointed-shaped ZnO nanoparticles significantly enhanced photocatalytic methane conversion activity.The photocatalytic activity of flower-like ZnO nanosheets is slightly lower than commercial irregular ZnO nanoparticles,but the C^(2+)reaction selectivity is higher.The hexagonal prism ZnO nanorods show extremely low photocatalytic reactivity,but still show a similar selectivity.The pro-catalyst with appropriate morphology and crystal facet is crucial for improving the photocatalyst performance.