Oxidative dehydrogenation of ethane to ethene on alumina-supported molybdenum-based catalysts modified by vanadium and phosphorus

Gamma-alumina-supported MoO x , MoVO x (Mo/V = 11) and MoVPO x (Mo/V = 11, V/P = 1) catalysts were prepared and their properties studied by several techniques (EDX-SEM, XRD, XPS, LRS, TPR). Acid–base and catalytic properties were determined by carrying out 2-propanol decomposition and oxidative dehydrogenation of ethane to ethene, respectively. In situ X-ray diffraction and X-ray photoelectron spectroscopy after pre-treatment were carried out in redox conditions (with H 2 /N 2 , C 2 H 6 /N 2 as reducing and O 2 /N 2 as oxidant). The catalytic performance increases along MoO x x x series. Analyses of MoVPO x show that part of Mo is stabilised as Al 2 (MoO 4 ) 3 and that the surface is made up from single or mixed Mo and V oxospecies. Vanadium increases the reducibility of the catalyst as shown by TPD and XPS. Both the acid–base and redox properties are responsible for the catalytic properties of MoVPO x , which are also related to the coordination of Mo active species.