Ir_(0.08)Ti_(0.92)O_2及其载Pt催化剂的制备与电催化性能

Preparation and Electrocatalytic Properties of Ir(0. 08)Ti_(0. 92)O_2 and Pt/Ir_(0. 08)Ti_(0. 92)O_2

采用TiN浸渍热分解法制备了低铱含量Ir0.08 Ti0.92 O2纳米粉体,再通过微波辅助制备Pt/Ir0.08 Ti0.92 O2催化剂,并与采用传统亚当斯法制备的IrO2和商品化Pt/C进行对比研究.利用X射线衍射（ XRD）、透射电子显微镜（SEM）、 X射线能量散射谱（EDS）和 X射线光电子能谱（XPS）对产物进行了分析.结果表明, Ir0.08 Ti0.92 O2是一种纳米棒状金红石相固溶体,直径约15 nm,担载Pt粒度5~7 nm,其中本体Ir/Ti原子比为0.084：0.916,表面Ir/Ti原子比为0.296：0.704,表明Ir在表面发生富集.经稳态极化曲线和线性扫描伏安测试得到析氧反应的本征催化活性由高到低为 Ir0.08 Ti0.92 O2〉Pt/Ir0.08 Ti0.92 O2〉IrO2,前两者性能相近；Pt/Ir0.08 Ti0.92 O2的氧还原反应活性低于Pt/C,需进一步优化载Pt粒度.研究结果表明, Ir0.08 Ti0.92 O2既是高效、低成本的析氧反应催化剂,也是高性能载体材料,这使Pt/Ir0.08 Ti0.92 O2作为双效催化剂在成本、催化性能和稳定性上具有更大优势,也可作为优异的析氢反应催化剂.

Ir0. 08 Ti0. 92 O2 nanopowder with low Ir loading was prepared by TiN impregnation-thermal decomposi-tion method, and then Pt/Ir0. 08 Ti0. 92 O2 electrocatalyst was obtained by microwave assisted hydrothermal synthe-sis method. X-ray diffractometer（XRD）, transmission electron microscope（TEM）, energy dispersive spec-trometer（ EDS） and X-ray photoelectron spectrometer（ XPS） were used to analysis the morphologies and com-position of the products. Ir0. 08 Ti0. 92 O2 showed to be stick-like nanoparticles with the diameter of 15 nm, and IrO2 and TiO2 formed a solid solution with rutile phase, the diameter of Pt nanoparticles on Ir0. 08 Ti0. 92 O2 was 5-7 nm. Moreover, Ir/Ti molar ratio in interior support was 0. 084：0. 916, whereas that on the support sur-face was 0. 296：0. 704, indicating the surface accumulation of Ir. Polarization curves and linear sweep volta-mmetry（ LSV） were performed to determine their electrocatalytic properties, compared with those of IrO2 by traditional Adams-fusion method and commercial Pt/C. The results showed that the catalytic activity towards the oxygen evolution reaction（ OER） was as follows：Ir0. 08 Ti0. 92 O2〉Pt/Ir0. 08 Ti0. 92 O2〉IrO2 （ the former two were almost the same） . However, catalytic activity of Pt/Ir0. 08 Ti0. 92 O2 towards the oxygen reduction reaction（ ORR） was lower than that of Pt/C, showing that a further optimization of Pt particle size was required. Therefore, Ir0. 08 Ti0. 92 O2 can be used not only as a low-cost and efficient OER catalyst but also as a suitable support mate-rial, which promotes Pt/Ir0. 08 Ti0. 92 O2 as a promising dual-functional catalyst with more advantage in cost, cata-lytic property and stability, as well as an excellent hydrogen evolution reaction （ HER ） catalyst in acidic medium.