A confined growth strategy to construct 3DOM SiO₂ nanoreactor in-situ embedded Co₃O₄ nanoparticles catalyst for the catalytic combustion of VOCs: Superior H₂O and SO₂ resistance

SO2 poisoning is a common problem in the catalytic combustion of volatile organic compounds (VOCs). In this work, we took three-dimensionally ordered macroporous and mesoporous (3DOM) SiO2 as the nanoreactor to protect active sites from SO2 erosion in the catalytic combustion of benzene. Simultaneously, the confined growth of metal active nanoparticles in the multistage pore is also full of challenges. And we successfully confined Co3O4 nanoparticles (NPs) in macroporous and mesoporous channels. Interestingly, the precursors' growth in the pore was controlled and nanoreactors with different pore sizes were prepared by adjusting the loading amount and preparation methods. It is discovered that the Co3O4 NPs confined in 3DOM SiO2 nanoreactor showed superior sulfur and water resistance. Density functional theory (DFT) calculations verified that the Co-Si catalyst had high SO2 adsorption energy (-0.48 eV), which illustrated that SO2 was hard to attach to the surface of the Co-Si catalyst. The SiO2 nanoreactor had low SO2 adsorption energy (-5.15 eV), which indicated that SO2 was easily absorbed on SiO2 nanoreactor. This illustrated that the SiO2 nanoreactor could protect effectively active sites from SO2 erosion.