TiO_2纳米棒载Pd催化剂的制备及其对甲酸的电催化氧化

摘要

利用水热合成和无机溶胶法,分别制备了具有棒状（TiO2-R）和无规则结构（TiO2-I）的锐钛矿相TiO2,并以之为载体制备得到Pd/TiO2电催化剂.循环伏安测试显示,与无规则TiO2相比,具有棒状结构的TiO2载Pd催化剂对甲酸氧化的电催化性能提高了70%;计时电流测试显示,运行3000 s后,甲酸在棒状TiO2载Pd催化剂上的氧化电流是无规则TiO2载Pd催化剂的16倍.其原因可能与TiO2纳米棒拥有更好的电子传导性且表面拥有较多的活性含氧基团有关,从而能够有效提高催化剂对甲酸氧化的电催化活性和抗毒化性能.%TiO2 nanorods （TiO2-R） and irregular TiO2 （TiO2-I） with anatase phase structure are synthesized by hydrothermal synthesis and inorganic sol gel method, respectively. Using as-prepared TiO2 as support, Pd/TiO2 catalysts are prepared by using sodium ethylenediamine tetracetate （EDTA） as complexing agent and NaBH4 as reductant. The studies of transmission electron microscopy （TEM） and X-ray diffraction （XRD） reveal that the average particle size of Pd/TiO2-R catalyst is very similar to that of Pd/TiO2-I catalyst. Cyclic voltammetry measurements show that the peak current of formic acid oxidation at Pd/TiO2-R catalyst increases by 70%. Chronoamperometric measurements indicate that the current density at the Pd/TiOa-R catalyst electrode at 3000 s is almost 16 times larger than that at the Pd/TiO2-I catalyst electrode. These electrochemical experiments show that the electrocatalytic activity and long-term operation stability of Pd/TiO2-R catalyst are much better than that of Pd/TiO2-I catalyst for formic acid oxidation in acidic media, indicating that TiO2 nanorods support material can effectively promote the electrocatalytic activity and stability of Pd catalyst for formic acid electrooxidation. Likely, TiO2 nanorods possess good electronic conductivity and abundant surface oxygen-containing groups, which improve the electrocatalytic activity and the anti-poisoned performance of Pd catalyst for the formic acid electrooxidation. Thus, TiO2 nanorods with anatase phase structure possess the potential application prospect in direct formic acid fuel cell （DFAFC）.