Relationship between bulk phase, near surface and outermost atomic layer of VPO catalysts and their catalytic performance in the oxidative dehydrogenation of ethane. - Ivars-Barceló, Francisco; Hutchings, Graham J.; Bartley, Jonathan K.; Taylor, Stuart H.; Sutter, Peter; Amorós, Pedro; Sanchis, Rut; Solsona, Benjamín (Journal of Catalysis, 2017)