Abstract: Pt nanocrystals(NCs) have been used as the catalyst for many hydrogenation reactions due to their good catalytic performance. Their catalytic activity and selectivity are strongly dependent on their nanostructure(morphology and size). According to Gibbs-Wulff theory,the morphology and size of NCs can be effectively controlled by certain capping agent. In this paper,various biomolecules,including DNA basic groups (adenine,guanine,thymine,cytosine) and corresponding nucleosides,have been employed as capping agent to control the size and shape of Pt NCs. NaBH₄ has been used to reduce platinum precursor(H₂PtCl₆) to prepare Pt NCs in water solution. The reduction of p-nitrophenol(p-NIP) by H₂ was employed as model reaction to evaluate the catalytic performance of as-prepared Pt NCs. Experimental results show that capping agent of biological molecules has a significant effect on the regulation of Pt NCs. Pt NCs with multiple morphologies and sizes have been successfully prepared. Simultaneously,the as-prepared Pt NCs showed precisely controllable activity for the hydrogenation of p-NIP. The TOF_ave of the Pt NCs regulated by guanosine,adenine,thymine are twice as much as that of the catalyst without any capping agent. Among all the catalysts,the adenine capped one showed the highest catalytic activity.

Key words: Pt nanocrystals, catalysis, hydrogenation, capping agent, nanostructure

摘要： 贵金属纳米晶对加氢反应具有良好的催化性能，特别是Pt纳米晶，其催化活性和选择性与纳米晶的纳米结构（形貌和尺寸）密切相关。由Gibbs-Wulff晶体生长定律可知，通过加入特定结构的封端剂可以有效控制纳米晶的形貌和尺寸。本文采用NaBH₄在水溶液中还原Pt的前体H₂PtCl₆制备Pt纳米晶，并将其用于催化对硝基苯酚（p-NIP）的加氢反应。实验系统研究了碱基分子（如腺嘌呤A、鸟嘌呤G、胸腺嘧啶T、胞嘧啶C）及对应的核苷分子对Pt纳米晶构型和催化加氢活性的调控规律。研究发现，碱基分子和核苷分子对于Pt纳米晶的形貌以及尺寸具有明显的调控作用，通过不同结构生物分子的精密调控，实验制备得到了形貌和尺寸各异的Pt纳米晶。同时，所得Pt纳米晶在p-NIP的加氢反应中表现出了精密可调的催化性能。鸟嘌呤核苷、腺嘌呤核苷、β-胸腺嘧啶核苷调控制备的Pt纳米催化剂的TOF_ave均可达到无调控剂制备得到的催化剂的两倍以上，其中腺嘌呤核苷调控制备得到的Pt催化剂性能最好。

关键词: Pt纳米晶, 催化, 加氢, 封端剂, 纳米结构