Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Direct growth of ultra-long platinum nanolawns on a semiconductor photocatalyst | Shen et al. Nanoscale Research Letters 2011 6 380 http content 6 1 380 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Direct growth of ultra-long platinum nanolawns on a semiconductor photocatalyst Yu-Lin Shen1 Shih-Yun Chen2 Jenn-Ming Song3 Tzu-Kang Chin3 Chu-Hsuan Lin4 and In-Gann Chen5 Abstract A template- and surfactant-free process thermally assisted photoreduction is developed to prepare vertically grown ultra-long Pt nanowires NWs about 30-40 nm in diameter 5-6 gm in length and up to 80 NWs 100 gm2 in the wire density on TiO2 coated substrates including Si wafers and carbon fibers with the assistance of the photocatalytic ability and semiconductor characteristics of TiO2. A remarkable aspect ratio of up to 200 can be achieved. TEM analytical results suggest that the Pt NWs are single-crystalline with a preferred 111 growth direction. The precursor adopted and the heat treatment conditions are crucial for the yield of NWs. The photoelectrons supplied by TiO2 gives rise to the formation of nano-sized Pt nuclei from salt melt or solution. The subsequent growth of NWs is supported by the thermal electrons which also generated from TiO2 during the post thermal treatment. The interactions between the ions and the electrons in the Pt TiO2 junction are discussed in this study. Introduction Platinum has become a crucial material due to its outstanding catalystic characters in fuel-cell technology hydrogenation reaction three-way automobile catalytic conversion and gas sensing 1-4 . A great deal of effort has been devoted to the synthesis of one-dimensional Pt nanostructures however it still remains a grand challenge to synthesize long and oriented single-crystalline Pt nanowires NWs . Table 1 summarizes the relevant reports concerning template-free chemical means for preparing Pt NWs. Xia et al. 5-7 have demonstrated the synthesis of single crystalline Pt NWs on polymeric ceramic or metallic substrate by a polyol
