Pore structure effect of support in Ni-Bi-O/mesoporous silica catalyst on oxidative dehydrogenation of n-butane to butadiene

•Oxidative dehydrogenation of n-butane depends on SiO2 species and pore size.•The order of butadiene yield as SBA-15 > SiO2 foam > MCM-41 > conventional silica.•The enhanced activity is related to active NiO on Bi2O3-a (a = 0.2-0.4) phase.•The presence of strong basic with weak/moderate acid sites plays an important role.•The Bi2O3-a phase serves as an active phase for dispersing NiO on the catalyst.