Defect‐induced Synthesis of Highly Dispersed Hydroxyapatite‐Supported Vanadium Oxide for the Oxidative Dehydrogenation of Cyclohexane

Abstract Hydroxyapatite (HAP) contains abundant defect sites and easily releases hydroxyl groups to produce new vacancies under calcination at high temperature. The highly dispersed VO x /HAP catalyst was prepared by an impregnation method using these defects as inducement. VO x species with different structures were analysed by XRD, XPS, H 2 ‐TPR, Raman and UV–vis spectroscopy. At low calcination temperatures (500 °C and 600 °C), the V species are mainly V 2 O5 crystals. At high calcination temperatures (above 700 °C), VO x on the HAP surface fills these defect sites and strongly interacts with HAP to form Ca−O−V or P−O−V bands. These scattered defects improved the dispersion of V species. These highly dispersed VO x /HAP catalysts were used for oxidative dehydrogenation (ODH) of cyclohexane to cyclohexene. The highly dispersed VOx/HAP catalyst showed a high selectivity for cyclohexene, and the selectivity reached 48.2 % when the conversion of cyclohexane was 13.1 % at 410 °C.