Confining shell-sandwiched Ag clusters in MnO₂-CeO₂ hollow spheres to boost activity and stability of toluene combustion

Supported noble metal catalysts have the promising application in volatile organic compounds (VOCs) catalytic combustion but suffer from the deactivation due to noble metal sintering at high temperatures. Herein, we report the construction of shell-sandwiched MnO₂-Ag-CeO₂ hollow spheres with remarkable sintering resistance and high activity in toluene combustion. Ag clusters were sandwiched between outer MnO₂ and inner CeO₂ shell to enlarge and stabilize metal–support active interface. The unique hollow structure could alter the electronic states of catalysts sites and increase the adsorbed site of reactant molecules. Meanwhile, Mn–Ag–Ce multi-interfaces in MnO₂-Ag-CeO₂ could facilitate the sustainable activation and the stable release of oxygen species via a tandem transfer. The oxygen species at Ag–Mn interface perimeter were instantly replenished by Ag–Ce interface to accelerate a deep oxidation of intermediates, guaranteeing the opening of benzene ring to generate maleic anhydride. This investigation provides a promising method for constructing efficient and sintering-resistant cluster catalysts for VOCs oxidation.