In this study, a novel three-dimensional (3D)-OMm-Co₃O₄/SiO₂-0.5AP (OMm = ordered macro–meso porous, AP = aluminum phosphate) monolithic catalyst was for the first time constructed successfully with the hierarchical Co-phyllosilicate ultrathin nanosheets growth on the surface of 3D printed ordered macropore–mesoporous SiO₂ support. On the one hand, we discovered that the construction of ordered macropore–mesoporous structures is beneficial to the diffusion and adsorption of reactants, intermediates, and products. On the other hand, the formation of hierarchical Co-phyllosilicate ultrathin nanosheets could provide more active Co^&+ species, abundant acid sites, and active oxygen. The above factors are in favor of improving the catalytic performance of benzene oxidation, and then a 3D-OMm-Co₃O₄/SiO₂-0.5AP catalyst exhibited the superior catalytic activity. To explore the effect of catalysts structure and morphology, various Co-based catalysts were also constructed. Simultaneously, the 3D-OMm-Co₃O₄/SiO₂-0.5AP catalyst has excellent catalytic performance, water resistance, and thermal stability in the catalytic combustion of benzene due to the strong interactions between Co^&+ species and SiO₂ in the phyllosilicate. Therefore, this study proposes a new catalyst synthesis method through 3D printing, and presents considerable prospects for the removal of VOCs from industrial applications.

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 multi-stage 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.