A solvent‐free induced self‐assembly technology for the synthesis of nitrogen‐doped ordered mesoporous polymers (N‐OMPs) is developed, which is realized by mixing polymer precursors with block ...copolymer templates, curing at 140–180 °C, and calcination to remove the templates. This synthetic strategy represents a significant advancement in the preparation of functional porous polymers through a fast and scalable yet environmentally friendly route, since no solvents or catalysts are used. The synthesized N‐OMPs and their derived catalysts are found to exhibit competitive CO2 capacities (0.67–0.91 mmol g−1 at 25 °C and 0.15 bar), extraordinary CO2/N2 selectivities (98–205 at 25 °C), and excellent activities for catalyzing conversion of CO2 into cyclic carbonate (conversion >95% at 100 °C and 1.2 MPa for 1.5 h). The solvent‐free technology developed in this work can also be extended to the synthesis of N‐OMP/SiO2 nanocomposites, mesoporous SiO2, crystalline mesoporous TiO2, and TiPO, demonstrating its wide applicability in porous material synthesis.
A novel and green strategy in which no solvents are used, for the fast synthesis of nitrogen‐doped ordered mesoporous polymers (N‐OMPs) is developed. The N‐OMPs display competitive CO2 capacities and extraordinary CO2/N2 selectivities, as well as excellent activity for catalytic conversion of CO2. The methodology can also be extended to the synthesis of N‐OMP/SiO2 nanocomposites, mesoporous SiO2, TiO2, and TiPO.
Because CO2 is the main greenhouse gas, its capture and catalytic conversion are thought to be significant issues to be solved at the current time. Given the thermodynamically stable and inert nature ...of CO2, it is highly desirable to develop advanced catalysts to facilitate the transformation of CO2 to other high-value-added chemicals under mild conditions. Within this regard, porous organic polymers (POPs), featuring large surface areas, high thermal stabilities, diverse building blocks, and tunable porous structures, are an ideal platform for the construction of heterogeneous catalysts for CO2 conversion. Incorporating active sites that are capable of activating CO2 and/or substrates into the frameworks of POPs can facilitate CO2 conversion. In this Review, the most recent advances in the design and synthesis of POP-based heterogeneous catalysts for the conversion of CO2 are summarized. We mainly focus on the synthetic strategies researchers have used for incorporating active sites into POP frameworks to prepare heterogeneous catalysts for CO2 conversion, including N-doping, metalation, and ionic functionalization. Problems remaining to be addressed in this field are analyzed, and future directions are outlined.
We report here the successful synthesis of highly pyridinic nitrogen doped, graphitized, ultra-hollow carbon frameworks (N-HCF-
T
s, where
T
stands for the carbonization temperature)
via
a ...template-free temperature-directed growth route, using dicyandiamide and glucose as precursors. N-HCF-
T
s have ultra high pyridinic nitrogen contents (up to 14.9 wt%), abundant meso–macropores, large specific surface areas (897–1434 m
2
g
−1
), and ultra large pore volumes (4.47–8.47 cm
3
g
−1
). The structural characteristics of the ultra high pyridinic nitrogen sites, abundant meso–macropores, and graphitized and ultra-hollow frameworks make N-HCF-Ts highly efficient and stable electrocatalysts for the oxygen reduction reaction. The most positive reduction potential was evident for N-HCF-900 at 0.83 V (
vs.
the RHE), which is even comparable to that of commercial (20 wt%) Pt/C and much better than those of most of the various nitrogen doped carbon-based metal-free electrocatalysts.
Ionic liquids based heteropolyacid hybrid (ILs-HPA) with both Brønsted and Lewis acid sites were prepared, which exhibit superior activities in esterification and biomass conversion.
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...A class of Brønsted–Lewis acid bifunctionalized ionic liquids based heteropolyacid hybrid (BLA-ILs-HPA) solid acids were developed by combining the double sulfonic groups grafted, ionic liquids based heteropolyacid hybrid with Lewis acidic centers (M = Zn, Co, Fe, Ni, Cu). The prepared BLA-ILs-HPA show both Brønsted and Lewis acidic sites with extremely-high acid strength and enhanced stabilities, as determined by FT-IR, Py-IR, TG, XPS and 31P solid state NMR results. BLA-ILs-HPA were successfully applied in esterification camphene with acetic acid to produce isobornyl acetate, and dehydration of glucose to produce 5-hydrozymethylfural. BLA-ILs-HPA show enhanced catalytic activities in comparison with various acid catalysts. The effects of reaction temperatures, initial reactant molar ratio, catalyst dosage, and reaction time were studied in detail. The optimal reaction conditions were obtained, and the experimental data was successfully correlated by a pseudohomogeneous (PH) reaction kinetic model in the temperature range of 313.15–333.15 K. The calculated values obtained by the reaction kinetic model were in good agreement with the experimental data. Moreover, as a heterogeneous reaction catalyst, BLA-ILs-HPA can be recovered by simple treatment. After six times cycling, the decreasing in the catalytic activity of BLA-ILs-HPA could not be observed significantly, suggesting their good reusability.
The activation of H2O is a key step of the COS hydrolysis, which may be tuned by oxygen vacancy defects in the catalysts. Herein, we have introduced Cu into Co3O4 to regulate the oxygen vacancy ...defect content of the catalysts. In situ DRIFTS and XPS spectra reveal that COS and H2O are adsorbed and activated by oxygen vacancy. The 10 at% Cu doped Co3O4 sample (10CuCo3O4) exhibits the optimal activity, 100% of COS conversion at 70 °C. The improved oxygen vacancies of CuCo3O4 accelerate the activation of H2O to form active OH. COS binds with hydroxyl to form the intermediate HSCO2−, and then the activated –OH on the oxygen vacancy reacts with HSCO2− to form HCO3−. Meanwhile, the catalyst exhibits high catalytic stability because copper species (Cu+/Cu2+) redox cycle mitigate the sulfation of Co3O4 (Co2+/Co3+). Our work offers a promising approach for the rational design of cobalt-related catalysts in the highly efficient hydrolysis COS process.
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•Cu doping promotes the formation of oxygen vacancy on Co3O4 surface.•Oxygen vacancies activate the adsorbed H2O and COS and accelerate the hydrolysis reaction.•The optimal Cu/Co3O4 catalyzes COS hydrolysis with almost 100% conversion at 70 °C.•The probable catalytic hydrolysis process has been proposed based on the detected intermediate.
Efficient and stable solid catalysts with good catalytic properties in esterifications and acylation were successfully synthesized from sulfonation of swelling mesoporous polydivinylbenzenes (PDVB) ...by chlorosulfonic acid in CH
2Cl
2.
Efficient and stable solid acid catalysts, sulfonic groups functional swelling mesoporous polydivinylbenzenes (PDVB-
x-SO
3Hs), were synthesized from sulfonation of swelling mesoporous polydivinylbenzenes (PDVB-
xs) by chlorosulfonic acid in CH
2Cl
2. Nitrogen adsorption–desorption isotherms showed that PDVB-
x-SO
3Hs have high surface area and abundant mesoporosity. Elemental analysis and acid–base titration techniques showed that PDVB-
x-SO
3Hs have high concentration of sulfonic groups. Esterifications of acetic acid with cyclohexanol, hexanoic acid with ethanol, lauric acid with ethanol and acylation of anisole with acetyl chloride showed that PDVB-
x-SO
3Hs are more active than arenesulfonic, propyl-sulfonic groups functional mesoporous silicas (SBA-15-Ar-SO
3H, SBA-15-Pr-SO
3H) and strongly acidic ion-exchange resin (Amberlyst 15). The superior performance of PDVB-
x-SO
3Hs is attributed to their unique features including large surface area, abundance of mesoporosity as well as high content of sulfonic groups.
The development of highly‐efficient catalysts for conversion of glucose and fructose to 5‐hydroxymethylfurfural (HMF) is of great importance. In this work, theoretical simulations form the basis for ...rational design and synthesis of a superhydrophobic mesoporous acid, that can completely prevent HMF hydration, giving HMF as sole product from full conversion of fructose. Interestingly, the combined superhydrophobic solid acid and superhydrophilic solid base catalysts are very efficient for one‐pot conversion of glucose to HMF, giving a yield as high as 95.4 %. The excellent catalytic data in the conversion of glucose to HMF is attributed to the unique wettabilities of the solid acid and base catalysts.
Superdry: Based on theoretical simulation, superhydrophobic mesoporous acid (P‐SO3H‐154) was rationally designed and successfully synthesized. The superhydrophobic acid could completely prevent HMF hydration, generating a sole HMF product from full conversion of fructose. Interestingly, the combined catalysts of superhydrophobic solid acid and superhydrophilic solid base are very efficient for one‐pot conversion of glucose to HMF, resulting in a yield as high as 95.4 %.
•SBA-16 and CoCe/SBA-16 structures are characteristic of a cubic Im3m symmetry.•A highly regular mesoporous structure, high SBET and Dv exist in the catalysts.•Addition of ceria can greatly improve ...the oxidation properties compared to Co/SBA-16.•CoCe(18:1)/SBA-16 exhibits the highest catalytic activity for benzene oxidation at 265°C.
In this investigation, SBA-16 was used to support metal (M=Cr, Mn, Fe, Co, Ni, Cu) oxides and ceria catalysts for the complete oxidation of benzene. The influence of a ceria promoter on the structure of SBA-16 and the catalytic performance of Co/SBA-16 were investigated. Mesoporous SBA-16 was found to have high surface area (472.1m2/g) and large pore volume (0.69cm3/g). The mesoporous, cage-like structure of SBA-16 was maintained throughout the preparation of CoCe supported catalysts. The addition of ceria promoted the reduction of cobalt oxide at a lower temperature and greatly affected its catalytic activity. These effects could be attributed to the good dispersion of Co3O4 on SBA-16 and the strong interaction between Co3O4 and CeO2. Catalysts with appropriate Ce greatly enhanced the activity of Co/SBA-16 for complete benzene oxidation; the catalyst CoCe(18:1)/SBA-16 exhibited the highest activity at 265°C. The high catalytic activity can likely be attributed to the high dispersion of Co3O4 on SBA-16, the high SBET, and the strong interaction between Co3O4 and CeO2.
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