Main-group metal oxides should poss

Main-group metal oxides should possess inherent advantagesover transition metal oxides in terms of selectivity to olefins astheir unique electronic properties with fully occupied d-orbitalslead to easy desorption of the generated alkenes.25,26 In turn, itis generally considered that main-group metals and their oxidesare catalytically inactive due to the lack of a combination ofempty and filled host orbitals, which is vital for electronicprocesses involved in the elementary steps of catalyticcycles.27−31 This explains why few studies on inherentlyselective main-group metal oxides as active sites to activate theC−H bond have been reported in oxidative dehydrogenationas far as we know. It has been clarified that atomicallydispersed metal sites such as noble and transition metalspossess unique electronic and atomic structures compared withtheir nanoparticle and M−O−M oligomer counterparts, whichmay exhibit beneficial properties for catalytic applica-tions.