Au纳米粒子/双层TiO_2周期结构的制备及其对乙醇的电催化性质

Fabrication of Au Nanoparticles/Bilayer TiO_2 Nanotube Periodical Structure and Electrocatalytic Oxidation of Ethanol

利用二次阳极氧化法成功制备了双层TiO_2纳米管周期结构。通过改变氧化电压可以有效地调整双层TiO_2纳米管的管径,从而控制样品的形貌。通过实验优化确定双层TiO_2周期结构的制备条件为一次氧化电压60 V,二次氧化电压40 V。利用原位光还原法,在TiO_2周期结构表面负载了Au纳米粒子并研究了前驱体溶液浓度与光照时间对样品的影响。在0.05 mmol/L HAu Cl_4溶液中光照90 min后得到的Au纳米粒子具有最优的形貌与分布。这种绿色的原位光还原法因为避免使用保护剂与还原剂而有效提高了Au纳米粒子的催化活性。制备所得的Au/TiO_2周期异质结构可以直接作为工作电极用于乙醇的电催化氧化,并表现出了良好的催化活性与稳定性。除了Au纳米粒子,其他金属纳米粒子如Ag、Pd、Cu等均可通过该方法成功负载于双层TiO_2纳米管周期结构上。这种新型的异质结纳米结构作为燃料电池的阳极材料表现出了巨大的潜力。

The bilayer TiO2 nanotube periodical structure was fabricated by a two-step anodization method. The morphology of this bilayer TiO2 nanotube could be controlled by adjusting the tube diameter under different anodizing voltages. The optimized bilayer periodical nanostructure was obtained under a first voltage of 60 V and second voltage of 40 V. Au nanoparticles were then decorated onto the periodical TiO2 nanotube surface by using in-situ photoreduction. The influences of precursor concentration and irradiation time were investigated. The best morphology and distribution of Au NPs on TiO2 were obtained in 0.05 mmol/L HAu Cl4 solution accompanied by irradiation for 90 min. This green method of in-situ photoreduction greatly enhanced the catalytic activity of Au nanoparticles due to the fact of avoiding reducing and protective agents. As-prepared Au/TiO2 periodical hetero-nanostructures could be directly used as working electrode and showed good catalytic activity and stability for electrocatalytic oxidation of ethanol. Except for Au nanoparticles, other metal nanoparticles such as Ag, Pd, and Cu could also be decorated onto the bilayer TiO2 nanotube pe-riodical structure by using this method. This novel hetero-nanostructure shows great potential in application for preparing high efficient anode materials for fuel cell.