关键词: Pt纳米晶, 催化, 加氢, 封端剂, 纳米结构

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