Elezović N R, Babić B M, Vracar Lj M, Radmilović V R, Krstajić N V
Institute for Multidisciplinary Research, Belgrade, Serbia.
Phys Chem Chem Phys. 2009 Jul 7;11(25):5192-7. doi: 10.1039/b822249e. Epub 2009 Apr 9.
The hydrogen oxidation reaction (HOR) was studied at the home made TiO(x)-Pt/C nanocatalysts in 0.5 mol dm(-3) HClO(4) at 25 degrees C. Pt/C catalyst was first synthesized by modified ethylene glycol method (EG) on commercially used carbon support (Vulcan XC-72). Then TiO(x)-Pt/C catalyst was prepared by the polyole method followed by TiO(x) post-deposition. The synthesized catalyst was characterized by XRD, TEM and EDX techniques. It was found that Pt/C catalyst nanoparticles were homogenously distributed over carbon support with the mean particle size of about 2.4 nm. The quite similar, homogenous distribution and particle size were obtained for Pt/C doped by TiO(x) catalyst which was the confirmation that TiO(x) post-deposition did not lead to significant growth of the Pt nanoparticles. The electrochemically active surface area of the catalyst was determined by using the cyclic voltammetry technique.The kinetics of hydrogen oxidation was investigated by the linear sweep voltammetry technique at the rotating disc electrode (RDE). The kinetic equations used for the analysis were derived considering the reversible or irreversible nature of the kinetics of the HOR. It was found that the hydrogen oxidation reaction for an investigated catalyst proceeded as an electrochemically reversible reaction. The values determined for the kinetic parameters-Tafel slope of 28 mV dec(-1) and exchange current density about 0.4 mA cm(-2)(Pt) are in good agreement with usually reported values for a hydrogen oxidation reaction with platinum catalysts in acid solutions.
在自制的TiO(x)-Pt/C纳米催化剂上，于25℃的0.5 mol dm(-3) HClO(4)中研究了氢氧化反应（HOR）。首先通过改进的乙二醇法（EG）在商业用碳载体（Vulcan XC-72）上合成了Pt/C催化剂。然后通过聚烯烃法制备TiO(x)-Pt/C催化剂，随后进行TiO(x)后沉积。采用XRD、TEM和EDX技术对合成的催化剂进行了表征。发现Pt/C催化剂纳米颗粒均匀分布在碳载体上，平均粒径约为2.4 nm。对于掺杂TiO(x)的Pt/C催化剂，也获得了非常相似的均匀分布和粒径，这证实了TiO(x)后沉积不会导致Pt纳米颗粒显著生长。通过循环伏安法测定了催化剂的电化学活性表面积。在旋转圆盘电极（RDE）上，采用线性扫描伏安法研究了氢氧化反应的动力学。用于分析的动力学方程是根据HOR动力学的可逆或不可逆性质推导出来的。发现所研究催化剂的氢氧化反应以电化学可逆反应进行。所测定的动力学参数值——塔菲尔斜率为28 mV dec(-1)，交换电流密度约为0.4 mA cm(-2)(Pt)，与通常报道的铂催化剂在酸性溶液中氢氧化反应的值非常吻合。
