Preparation and characterization of zirconia-coated nanodiamonds as a Pt catalyst support for methanol electro-oxidation

Abstract

Zirconia-coated nanodiamond (ZrO2/ND) electrode material was successfully prepared by one-step isothermal hydrolyzing from ND-dispersed ZrOCl2.8H2O aqueous solution. High-resolution transmission electron microscopy reveals that a highly conformal and uniform ZrO2 shell was deposited on NDs by this simple method. The coating obtained at 90°C without further calcination was mainly composed of monoclinic nanocrystalline ZrO2 rather than common amorphous Zr(OH)4 clusters. The ZrO2/NDs and pristine ND powder were decorated with platinum (Pt) nanoparticles by electrodeposition from 5 mM chloroplatinic acid solution. The electrochemical studies indicate that Pt/ZrO2/ND catalysts have higher electrocatalytic activity and better stability for methanol oxidation than Pt/ND catalysts in acid.