Enhancement of the catalytic performance of a CNT supported Pt nanorod cluster catalyst by controlling their microstructure

Abstract

A novel Pt/CNT catalyst with a hierarchical structure was prepared. The effect of different morphologies of CNT supports on the catalyst microstructure and catalytic performance was studied. TEM tomography was used to analyse the real microstructure of the catalysts, including both the morphology of flower-like Pt clusters themselves and their distribution on the CNTs. The results revealed that Pt flowers were composed of nanorods, which dispersed in both the inner and outer tube surface of CNTs with larger inner tube diameter (TKCNTs). Comparing with the conventional Pt/CNT catalyst where Pt flowers only dispersed on the outer tube surface, the present Pt/TKCNT catalyst with the novel structure exhibited higher activity (enhanced to be ∼1.5 times higher current density) and better catalytic stability for methanol oxidation. Moreover, it displays ∼2 times higher activity for methanol electro-oxidation than that of CB supported Pt nanorod clusters. The results indicate that the catalytic performance of the Pt nanorods supported on different carbon supports depends on both carbon morphology and the distribution of the metal catalyst on the supports. The improved catalytic performance of the Pt/TKCNT catalyst with the novel hierarchical structure could be attributed to the confinement effect of TKCNTs.