TiO2纳米棒载Pd催化剂的制备及其对甲酸的电催化氧化

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.

Preparation of TiO2-Nanorods Supported Pd Catalyst and Its Electrocatalytic Oxidation on Formic Acid

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/TiO2-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 sta-bility of Pd catalyst for formic acid electrooxidation.Likely,TiO2 nanorods possess good electronic conduc-tivity 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).