He Chuansheng, Yang Linlin, Peng Xiaohui, Liu Shangheng, Wang Jia, Dong Chengyuan, Du Delin, Li Leigang, Bu Lingzheng, Huang Xiaoqing
State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Department of Nanoscience, Universitat de Barcelona, 08028 Barcelona, Spain.
ACS Nano. 2023 Mar 28;17(6):5861-5870. doi: 10.1021/acsnano.2c12735. Epub 2023 Mar 15.
Thickness regulation of transition metal hydroxides/oxides nanosheets with superior catalytic properties represents a promising strategy to enhance catalytic performance, but it remains an enormous challenge to achieve precise control, especially when it comes to the ultrathin limit (several atomic layers). In this work, a facile strategy of alkylamine-confined growth is proposed for the synthesis of thickness-tunable metal hydroxide/oxide nanosheets. Specifically, ultrathin cobalt hydroxide and cobaltous oxide hybrid (Co(OH)-CoO) nanosheets (Co-O NSs) with a thickness in the range of 2-6 nm (5-13 atomic layers) are synthesized by using alkylamines with different carbon chain lengths as the ligand to modulate vertical coordination ability. Co-O NSs with a thickness of 2 nm (Co-O NSs-2 nm) exhibit excellent oxygen evolution reaction (OER) performance with an overpotential of 278 mV at 10 mA/cm. The maximized number of active sites including oxygen vacancies, optimal adsorption strength, and the highest electrical conductivity are considered as the potential factors contributing to the excellent OER performance of Co-O NSs-2 nm. This work holds great significance for the precise thickness-tunable synthesis of transition metal layered hydroxide nanosheets with modulated and improved catalytic performance.
具有优异催化性能的过渡金属氢氧化物/氧化物纳米片的厚度调控是提高催化性能的一种有前景的策略，但实现精确控制仍然是一个巨大的挑战，尤其是在达到超薄极限（几个原子层）时。在这项工作中，提出了一种通过烷基胺限制生长的简便策略来合成厚度可调的金属氢氧化物/氧化物纳米片。具体而言，通过使用不同碳链长度的烷基胺作为配体来调节垂直配位能力，合成了厚度在2 - 6 nm（5 - 13个原子层）范围内的超薄氢氧化钴和氧化亚钴混合（Co(OH)-CoO）纳米片（Co-O NSs）。厚度为2 nm的Co-O NSs（Co-O NSs-2 nm）在10 mA/cm²时具有278 mV的过电位，表现出优异的析氧反应（OER）性能。包括氧空位在内的活性位点数量最大化、最佳吸附强度和最高电导率被认为是Co-O NSs-2 nm优异OER性能的潜在因素。这项工作对于精确厚度可调地合成具有调控和改善催化性能的过渡金属层状氢氧化物纳米片具有重要意义。
