Microporous exposure on catalytic performance of MoVNbTeOx mixed metal oxides in the oxidative dehydrogenation of ethane

•An effective post-treatment method was applied to enhance the activity of MoVNbTeOx catalysts.•A series of model catalysts for studying the relationship between pore volume and activity were obtained by a mild physical post-treatment method.•A good proportional linear relationship between the activity of the series model catalysts and their pore volumes was obtained.•The lattice oxygen content of MoVNbTeOx catalysts is not a major factor affecting the catalyst activity.•The amount of pore volume of the M1 MoVNbTeOx catalyst is the key factor for the catalyst activity.