Huang Yang, Mao Xinnan, Yuan Guotao, Zhang Duo, Pan Binbin, Deng Jun, Shi Yunru, Han Na, Li Chaoran, Zhang Liang, Wang Lu, He Lin, Li Youyong, Li Yanguang
State Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences, Lanzhou, 730000, China.
Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, 215123, China.
Angew Chem Int Ed Engl. 2021 Jul 12;60(29):15844-15848. doi: 10.1002/anie.202105256. Epub 2021 Jun 14.
The size modulation of catalyst particles represents a useful dimension to tune catalytic performances by impacting not only their surface areas but also local electronic structures. It, however, has remained inadequately explored and poorly elucidated. Here, we report the interesting size-dependent selectivity of electrochemical CO reduction on In O nanocrystals. 5-nm nanoparticles and 15-nm nanocubes with focused size distribution are prepared via a facile solvothermal reaction in oleylamine by carefully controlling a set of experimental parameters. They serve as the precatalysts, and are reduced to In nanocrystals while largely inherit the original size feature during electrochemical CO reduction. Catalyst derived from 15-nm nanocubes exhibits greater formate selectivity (>95 %) at lower overpotential and negligible side reactions compared to bulk-like samples (indium foil and 200-nm cubes) as well as the catalyst derived from smaller 5-nm nanoparticles. This unique size dependence is rationalized as a result of the competition among different reaction pathways by our theoretical computations. Smaller is not always better in the catalyst design.
催化剂颗粒的尺寸调制是一个有用的维度，不仅可以通过影响其表面积，还可以通过影响局部电子结构来调节催化性能。然而，这方面的研究仍不充分，阐释也很欠缺。在此，我们报道了氧化铟纳米晶体上电化学CO还原有趣的尺寸依赖性选择性。通过在油胺中进行简便的溶剂热反应，通过仔细控制一组实验参数，制备了尺寸分布集中的5纳米纳米颗粒和15纳米纳米立方体。它们作为预催化剂，在电化学CO还原过程中被还原为铟纳米晶体，同时很大程度上保留了原始尺寸特征。与块状样品（铟箔和200纳米立方体）以及由较小的5纳米纳米颗粒衍生的催化剂相比，由15纳米纳米立方体衍生的催化剂在较低过电位下表现出更高的甲酸盐选择性（>95%），且副反应可忽略不计。通过我们的理论计算，这种独特的尺寸依赖性是不同反应途径之间竞争的结果。在催化剂设计中，并非越小越好。
