Rational Design and Construction of Monolithic Ordered Mesoporous Co₃O₄@SiO₂ Catalyst by a Novel 3D Printed Technology for Catalytic Oxidation of Toluene

Abstract

Here, we report a novel 3D printed layered ordered mesoporous template that can encapsulate active Co-MOFs species in a confined way to achieve the goal of monolithic catalyst. The monolithic OM-Co3O4@SiO2–S catalyst can maintain a macroscopic porous layered structure and a microscopic ordered mesoporous structure. This monolithic OM-Co3O4@SiO2–S catalyst has excellent catalytic performance (T 90 = 236 °C), water resistance, and thermal stability in the catalytic combustion of toluene. The catalytic performance of the monolithic OM-Co3O4@SiO2–S catalyst is much better than that of many monolithic catalysts reported in the former. Among them, the introduction of binder aluminum phosphate (AP) can effectively enhance the rheological properties of the printing ink, achieve the purpose of ink writing monolithic layered porous material, enrich the acidic point of the monolithic catalyst, and increase the number of reactive oxygen species. This work reveals a novel monolithic catalyst forming strategy that can combine the advantages of ordered mesoporous materials with active species to form macro-layered porous materials and provide ideas and an experimental basis for the elimination of VOCs in industrial applications.

Significant Enhanced SO2 Resistance of Pt/SiO2 Catalysts by Building the Ultrathin Metal Oxide Shell for Benzene Catalytic Combustion

“…It was easy to see that all samples were dominated by chemisorbed oxygen species and adsorbed water molecules, and it was remarkable that the O wat species might be caused by many ordered mesoporous SiO 2 . 40 Previous results verified that the catalytic performance of samples could be improved by increasing the concentration of surface-active oxygen species. 43−45 In general, chemisorbed oxygen had better mobility than lattice oxygen, which meant that O ads were more active in the relevant oxidation reactions.…”

“…The characteristic peaks of O latt with a binding energy around 530.80–530.99 eV were attributed to the surface lattice oxygen species (O 2– ), and the O ads peaks were attributed to the chemisorbed oxygen species (O 2 – , O – and O 2 2– ) with a binding energy of 532.99–533.15 eV. , Furthermore, the peaks of O wat were attributed to adsorbed water molecular or hydroxyl groups with a binding energy around 533.52–533.99 eV. It was easy to see that all samples were dominated by chemisorbed oxygen species and adsorbed water molecules, and it was remarkable that the O wat species might be caused by many ordered mesoporous SiO 2 . Previous results verified that the catalytic performance of samples could be improved by increasing the concentration of surface-active oxygen species. – In general, chemisorbed oxygen had better mobility than lattice oxygen, which meant that O ads were more active in the relevant oxidation reactions.…”

“…Among them, the order of adsorbed oxygen content was Pt/SiO 2 > Pt/SiO 2 @MgO > Pt/SiO 2 @ZnO > Pt/SiO 2 @MnO x , which was consistent with the activity. The abundant porous structure was conducive to the generation of more adsorbed oxygen species and may activate more lattice oxygen to promote the catalytic oxidation of benzene . Therefore, it was speculated that the higher the content of adsorbed oxygen, the better the catalytic activity.…”

“…The abundant porous structure was conducive to the generation of more adsorbed oxygen species and may activate more lattice oxygen to promote the catalytic oxidation of benzene. 40 Therefore, it was speculated that the higher the content of adsorbed oxygen, the better the catalytic activity. In addition, the surface acidic properties of the catalysts were explored via the NH 3 -TPD technique, as shown in Figure S5 and Table S2.…”

Lattice Compressive Strain of Co3O4Induced by Synthetic Solvents Promotes Efficient Oxidation of Benzene at Low Temperature

“…They can cause irreversible damage to humans. , Catalytic oxidation technology is one of the highly efficient technologies for eliminating VOCs, in which the role of catalysts is self-evident. , Since noble metal catalysts are limited by expensive cost and low lifetime, more and more research is now focused on developing low-cost, active, and stable transition-metal oxide (Co, Ce, Mn, etc.) for the catalytic oxidation of VOCs. − Among them, Co 3 O 4 has shown excellent activity for the catalytic oxidation of benzene series. − Co 3 O 4 spinel oxide is rich in Co 2+ and Co 3+ , and its cations occupy tetrahedral and octahedral sites in the lattice, respectively. Meanwhile, the oxygen atoms of Co 3 O 4 are located in the closely arranged cubic structure, which is highly active for the activation of C–H bonds in benzene series oxidation. − …”