Existence and Properties of Isolated Catalytic Sites on the Surface of β-Cristobalite-Supported, Doped Tungsten Oxide Catalysts (WOx/β-SiO2, Na-WOx/β-SiO2, Mn-WOx/β-SiO2) for Oxidative Coupling of Methane (OCM): A Combined Periodic DFT and Experimental Study

International audience