金属氧化物纳米催化的形貌效应

纳米结构催化剂的设计与制备是多相催化的核心问题之一．提高催化活性的传统方法是减小催化剂粒子的尺寸以暴露更多的表面活性位，即纳米催化中的尺寸效应，但这种方法往往带有一定程度的经验性和随机性．近年来，随着纳米材料科学的快速发展，在溶液体系中通过自下而上的合成技术已经可以在纳米尺度上有效调变固体催化剂粒子的形貌．通过纳米催化材料的形貌可控合成，可选择性地暴露高活性或特定能量晶面，从而大幅度提升催化反应活性、选择性和稳定性，也就是纳米催化中的形貌效应，这也是当前纳米催化研究的热点之一．本文以作者近年来研究的C0304、CeO2和Fe2O3为重点，总结了纳米结构金属氧化物在多相催化反应中的形貌效应，分析了氧化物暴露品面的化学性质对催化性能的作用机制．这种基于形貌效应的纳米催化不仅加深了在纳米尺度甚至原子层次上对催化剂构一效关系的认知，而且对设计和开发实用高效催化剂也具有重要的理论价值．

Morphology-dependent nanocatalysis on metal oxides

The design and fabrication of solid nanomaterials is the key issue in heterogeneous catalysis to achieve desired performance. Traditionally, the main theme is to reduce the size of the catalyst particles as small as possible for maximizing the number of active sites. In recent years, the rapid advancement in materials science has enabled us to fabricate catalyst particles with tunable morphology. Consequently, both size modulation and morphology control of the catalyst particles can be achieved independently or synergistically to optimize their catalytic properties. In particular, morphology control of solid catalyst particles at the nanometer level can selectively expose the reactive crystal facets, and thus drastically promote their catalytic performance. In this review article, we summarized our recent works on the morphology impact of Co304, CeO2 and Fe203 nanomateriials in catalytic reactions, together with related literature reports on morphology-dependent nanocatalysis of metal oxides, to demonstrate the importance of tuning the shape of oxide-nanocatalysts for prompting their activity, selectivity and stability, which is a rapidly growing topic in heterogeneous catalysis. The fundamental understanding of the active sites in morphology-tunable oxides that are enclosed by reactive crystal facets is expected to direct the development of highly efficient nanocatalysts.