High Acid Site Research Articles

Innovative microkinetic modelling-supported structure–activity analysis of Ni/ZSM-5 during vapor-phase hydrogenation of levulinic acid

The study examines Ni/ZSM-5 catalysts in vapor phase hydrogenation of levulinic acid (LA) under continuous flow conditions (ambient pressure, 210–250 °C). Advanced characterization revealed the interplay between Al and Ni. This was further reinforced by new approach of microkinetic modeling, which demonstrates a pioneering work on mathematical description of pulse H2 sorption, TPD kinetics, DRIFT-supported determination of sorption energy barriers and (de)sorption kinetics. The Ni/ZSM-5 (3.7 wt.% Ni, Si/Al = 28) emerged as the optimal choice for obtaining γ-valerolactone (GVL) as the desired product. Al-rich catalysts with high acid site amounts and low metallic Ni active site concentrations favored esterification, reducing hydrogenation activity, and impeding further hydrogenation of GVL to pentanoic/valeric acid (PA). To enhance PA formation, Ni/ZSM-5 (4 wt.% Ni, Si/Al = 750) with a high Si/Al ratio, was identified as crucial. The combination of described experiments and modelling is demonstrated beneficial for insightful investigation of the structure–activity relationship of Ni/ZSM-5 or any other mono/bi-functional catalysts.

Comparative study on Al-SBA-15 prepared by spray drying and traditional methods for bulky hydrocarbon cracking: Properties, performance and influencing factors

Mesoporous aluminosilicates Al-SBA-15 with large pore sizes and suitable acid properties are promising substitutes to zeolites for catalytic cracking of bulky hydrocarbons without molecular diffusion limitation. The conventional processes to synthesize Al-SBA-15 are time-consuming and often suffer from low “framework” Al contents. Herein, Al-SBA-15 microspheres are synthesized using the rapid and scalable microfluidic jet spray drying technique. They possess uniform particle sizes (45–60 μm), variable surface morphologies, high surface areas (264–340 m2/g), uniform mesopores (3.8–4.9 nm) and rich acid sites (126–812 μmol/g) and high acid strength. Their physicochemical properties are compared with the counterparts synthesized using traditional hydrothermal and evaporation-induced self-assembly methods. The spray drying technique results in a higher incorporation of aluminum (Al) atoms into the silica “framework” compared to the other two methods. The catalytic cracking efficiencies of 1,3,5-triisopropylbenzene (TIPB) on the Al-SBA-15 materials synthesized using the three different methods and nanosized ZSM-5 are compared. The optimal spray-dried Al-SBA-15 exhibits the best performance with 100 % TIPB conversion, excellent selectivity (about 75 %) towards the formation of deeply cracked products (benzene and propylene) and high stability. The catalytic performances of the spray-dried Al-SBA-15 with varying Si/Al ratios are also compared. The reasons for the different performances of the different materials are discussed, where the mesopores, high acid density and strength are observed to play the most critical role. This work might provide a basis for the synthesis of mesoporous rich metal-substituted silica materials for different catalytic applications.

Cyclophosphamide Loading and Controlled Release in MIL-100(Fe) as an Anti-breast Cancer Carrier: In vivo In vitro Study.

Biocompatible MIL-100 (Fe), a metal organic framework material, has recently attracted increasing attention in biomedical engineering. The high surface area, pore volume, and accessible Lewis acid sites make MIL-100 (Fe) a proper candidate for hydrophobic anticancer drug loading and storage. In this study, a novel investigation of cyclophosphamide (CP) -loaded MIL-100(Fe) (MIL- 100(Fe)/CP) and a simulation of drug loading at a molecular level is presented. This research used a facile synthesis method to prepare MIL-100(Fe), which addresses the high temperature and pressure challenges of synthesis methods. MIL-100(Fe) and MIL-100(Fe)/CP were characterized using x-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Fourier transform infrared (FTIR), and field emission scanning electron microscopy (FESEM). The carriers' drug loading and release behavior are determined by using UV-visible spectrophotometry. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay is applied to examine the biocompatibility and the anticancer effect of MIL-100(Fe)/CP on the human breast cancer cell line (MCF-7). In vivo</i> antitumor experiments and histological observation reveal inhibition properties of MIL-100(Fe)/CP on the tumor cells. MIL-100(Fe)/CP, with 37.41% drug payload, represents impressive antitumor activity.

One-pot synthesis of acrylic acid from glycerol over SBA-15 supported heteropoly acid catalysts: Influence of mesoporosity and acidity

Heteropoly acids (HPAs) of the Keggin type exhibit substantial Brønsted acidity and are commonly utilized as acid catalysts, particularly in acrylic acid synthesis via glycerol oxydehydration. The primary goal of this research is to comprehensively assess the morphological and physicochemical properties of SBA-15 supported HPAs (H4SiW12O40.xH2O, H3PW12O40.xH2O, and H3PMo12O40.xH2O). The synthesized catalysts were characterized via physisorption analysis, XRD, SEM, FT-IR, NH3-TPD, and H2-TPR. Furthermore, the catalyst's catalytic activity in acrylic acid synthesis via single-step liquid phase glycerol oxydehydration was evaluated by correlating its characteristics with glycerol conversion and acrylic acid yields. The PW/SBA-15 catalyst exhibited the best performance, with the highest acrylic acid yield reaching 17.5% at 87.8% glycerol conversion. Given that the partial oxidation of acrolein to acrylic acid necessitates an optimal level of redox properties, the superior performance of PW/SBA-15 was characterized by high acid sites and moderate oxidative capabilities.

Amphiphilic HZSM-5 for Cyclopentene Hydration at the Liquid-Liquid Interface in Pickering Emulsion.

Zeolite is considered an ideal catalyst for olefin hydration due to its high specific surface area and abundant acid sites. However, the immiscibility of the water-oil two phases in olefin hydration limits mass transfer, and the side reaction of etherification occurs acutely, resulting in a low yield of alcohol. Thus, water-oil amphiphilic HZSM-5 was prepared by sulfonating silanized zeolite. The successful introduction of organic and sulfonic acid groups is demonstrated by FT-IR, TG, and water contact angles. Amphiphilic HZSM-5 can stabilize the Pickering emulsion and catalyze cyclopentene hydration at the phase interface. In addition, NH3-TPD and Py-IR show that the amount of strong Bro̷nsted acid sites of zeolites increases significantly after sulfonation. This facilitates the rate-determining step of cyclopentene activation by H+ to form carbocation. Moreover, the nucleophilic side reactions are inhibited by a high concentration of H+. Finally, under the optimized reaction condition, the conversion of cyclopentene can achieve 5.066% with a selectivity of 85.37% to cyclopentanol, which almost reaches the reaction equilibrium.

Defect engineering enables synergistic action of hierarchical porosity and multifunctionality for efficient catalysis of diverse reactions

The limitations of embedding suitable functional groups as Brønsted and Lewis pairs in metal–organic materials hinder their application especially to promote catalysis reactions. Due to the generation abundance of unsaturated inorganic nodes upon partial ligand decarboxylation, Quasi-MOFs (Q-MOFs) are considered as a potential candidate for the installation of amino acids. Here for the first time, we demonstrated that Q-HKUST-1 possessing a Lewis acid site could be transformed into an excellent multifunctional chiral MOF (Q-HKUST-Cys), via post-synthetic modification by L-Cysteine. Applying this approach, we can fabricate a pore environment spatially decorated with multiple functional groups. The post-modified MOF has been characterized by a variety of techniques including PXRD, N2 sorption, 1HNMR, FT-IR, CD, and SEM/EDS mapping. Q-HKUST-Cys features unique properties, such as mesoporosity, high Lewis acid sites including Cu2+, Lewis base sites (NH2 group), Bronsted acid sites (COOH group), open channels, and optical activity. So, this chiral MOF exhibits excellent catalytic performance in various asymmetric reactions under mild conditions. The Q-HKUST-Cys is highly enantioselective heterogeneous and recyclable catalyst, in ring-opening of epoxide and nitroaldol reaction with up to 99 % ee, as well as 100 % and 90 % conversion, respectively. Besides, in the cycloaddition of CO2 to styrene-epoxide (STO), and production of the corresponding cyclic carbonate, this catalyst showed high performance (90 % conversion, 89 % ee) under mild conditions, at the atmospheric pressure of CO2 and in the solvent-free situation. The simultaneous presence of these properties makes Q-HKUST-Cys an attractive catalyst for the eco-friendly synthesis of fine chemicals through CC and CO bond formation. As a result, in this study, we showed that anchoring defective MOFs with multifunctional amino acids can be an effective approach for the utilization of synergistic effects in the promotion of many catalysis reactions.

Rh nanoparticles supported on porous hexagonal boron nitride nanorods with hierarchical structure for highly efficient hydroformylation of olefins

Hydroformylation would be a promising alternative for partial technological process in petrochemical industry because it is a 100% atom-economical route for large-scale production of aldehydes and alcohols from olefins and synthesis gas (H2 and CO). However, there are still a few problems such as cost-intensive recycling and harsh operating conditions etc. encountering in the ligand-modified cobalt and rhodium as homogeneous catalysts in practical applications. Responding to the challenges, to exploit heterogeneous catalysts especially supported catalysts is desired and needs to make more efforts. Here, porous boron nitride (p-BN) with hierarchical structure is designed through a facile thermal polymerization procedure for catalyst support. The p-BN possesses nanorod morphology assembled by numerous highly crystallized hexagonal boron nitride (h-BN) nanoparticles with the diameter of about 20 nm as building blocks, thereby forming abundant interparticle pores. The Rh nanoparticles are then supported on p-BN by an impregnation-borohydride reduction method using RhCl3 as metal precursor, and the obtained catalyst of Rh nanoparticle supported on p-BN (Rh/p-BN) is applied in hydroformylation of styrene. The high porosity and accessible boron acid sites arising from hierarchical structure of p-BN nanorods make Rh nanoparticles homogeneously disperse on the surface of p-BN nanorods and also keep the diameter about 5 nm without further aggregations. Just for this reason, Rh/p-BN exhibits excellent activity of styrene hydroformylation with the highest turnover frequency of styrene as high as 12000 h−1, in comparison with other supported catalysts using different catalyst supports. Besides the detailed investigation of the catalytic properties of Rh/p-BN under different reaction conditions, the recycle of Rh/p-BN is also conducted for five times during which there is no significant decrease in catalytic activity. The present findings indicates that the combination of catalyst support of p-BN and metal nanoparticle catalysts could be an attractive strategy for designing heterogeneous hydroformylation catalysts.

Impact of acid site concentration and temperature on the operating regime, activity and selectivity in methanol-to-olefins conversion over H-ZSM-5

The effect of Si/Al ratio on operating regime, activity and selectivity in methanol-to-olefins conversion has been assessed over H-ZSM-5 zeolites with high (Si/Al=25), moderate (Si/Al=40) and low (Si/Al=140) acid site concentration, in a wide temperature (325 – 450 °C) and space time range (0.44 – 110.0 kgcat s molMeOH-1). For Si/Al=25 no stable regime is achieved, shifting immediately from transition to deactivation, while Si/Al=140 always ensures stable operation. At lower Si/Al ratio and increasing temperature, reaction pathways shift to produce more C3-C5 olefins. Suppression of bimolecular methylation and hydride transfer in favour of monomolecular alkene cracking is at the origin of such behaviour, either by increased acid sites distance or due to reduced physisorbed concentrations and activation energy differences. The latter phenomena cause a peculiar conversion decrease with increasing temperature between 350 and 400 °C. Consistent, well-designed data acquisition allowed insights into the complex mechanism and the effect of catalyst properties and temperature thereon.

Insight into induction period of methanol conversion reaction: Reactivity of ethene-precursors over H-ZSM-5 zeolite is independent of Brϕnsted acid site density

A series of H-ZSM-5 (TZ-m, m represents different Si/Al ratios) has been prepared and their Methanol to Olefin (MTO) performance are investigated. By adjusting the catalyst weight of H-ZSM-5 loaded in the pulse micro-reactor, the total Brϕnsted acid sites (BAS) amount of TZ-m catalysts is unified. The resultant similar methanol conversion (∼24 %) over different TZ-m zeolites confirms that the MTO reaction is dominantly catalyzed by BAS. Nevertheless, the BAS density considerably influences the reaction pathways; more condensed BAS enhances the relative propagation of aromatic-based cycle to alkene-based cycle, and vice versa. However, isotopic co-feeding and switching experiment reveals that the reactivity of aromatic hydrocarbon pool (HCP) species, which has been considered as main ethene precursors, is almost independent of acid site density. Although large amounts of aromatics are generated via hydrogen transfer reactions on the sample with high acid site density, most of the confined aromatics function as coke precursors instead of active HCPs. The accumulation of such confined aromatics in zeolite channels further limits olefins mobility and their access to BAS, leading to decreased reactivity of alkene HCPs on high acid site-density samples.

Oxidation reaction mechanism of hydrothermal carbon microspheres with applications to transesterification after sulfonation

AbstractBackgroundAn efficient sulfonic acid‐type acid catalyst with high acid site density based on hydrothermal carbon microspheres (HCMs) has been developed. The reaction by which double bonds in the HCMs were oxidized to generate carboxyl groups was evaluated based on density functional theory calculations.ResultsSulfonic acid‐type HCMs (SHCMs) were prepared from HCMs through a three‐step process comprising oxidation, amidation and sulfonation. An analysis of the oxidation process indicated that the formation of carboxyl groups involved the activation of O2 molecules and CH bonds, the cleavage of CC bonds, the homolytic fission of peroxy acids and the coupling reactions of H• radicals. The formation of numerous carboxyl groups on the HCM surfaces was the key to obtaining SHCMs with a high acid density of 14.5 mmol g−1.ConclusionsThe SHCMs obtained exhibited good catalytic performance during the transesterification of waste frying oil with methanol. Reactions performed using a methanol/oil molar ratio of 9:1 at 90 °C for 5 h gave a fatty acid methyl ester yield of 85.56%. © 2022 Society of Chemical Industry (SCI).

An aluminum-grafted SBA-15-catalyzed conversion of glucose to 5-hydroxymethylfurfural

Environmentally friendly processes for preparing catalysts and converting glucose into 5-hydroxymethylfurfural (HMF) were studied under water-based conditions. A series of aluminum-grafted SBA-15 mesoporous silica with Si/Al molar ratios of 1.5–20 was prepared by tuning aluminum precursors, solvents, and the pH values in grafting. Among them, the 3Al-S15-w-pH 8 catalyst with high acid capacity and mixed acid sites of Lewis and Brønsted acids was fabricated by adjusting the pH value of the water-soluble aluminum precursor to 8 in a water medium. Thus, it converted 87% of glucose at 160 °C for 5 h in the water medium with 33% HMF selectivity. Moreover, the used 3Al-S15-w-pH 8 catalyst was easily regenerated by calcination in air, which was further used for converting glucose to HMF without losing its performance. Our findings provide new ideas for environmentally friendly catalyst preparation and biomass conversion methods, which can be readily applied to catalysis and bio-refining processes.

Enhanced Pt dispersion and catalytic properties of NaCl-promoted Pt/MFI zeolite catalysts for propane dehydrogenation

A simple and scalable method is presented for preparing propane dehydrogenation catalysts with superior catalytic properties. Pt distribution is significantly improved when the platinum precursor and a large amount of NaCl are introduced into the MFI zeolite by impregnation, and after calcining and fixing the active components in the insoluble form, the excess of inert salt is washed with water. NaCl promotes Pt dispersion, prevents sintering during calcination , and effectively suppresses zeolite acidity. Washing after the calcination of Pt-containing catalysts further increases the catalyst activity and stability due to the redispersion of water-soluble chlorinated Pt compounds. High external surface acid site concentrations, Na/Pt atomic ratios of 40–70, calcination temperatures of 400–500 °C, washing with water, and the order of component introduction when the excess NaCl and the precursor of Pt are calcined jointly contribute to improved Pt dispersion and catalyst stability. • Impregnation-calcination-washing method of Pt catalysts preparation is proposed. • Calcination of the Pt precursor with an excess of NaCl increases the dispersion of Pt. • NaCl excess contributes to stability of propane dehydrogenation MFI-zeolite catalysts. • Washing after calcination improves the activity and stability of Pt/MFI catalysts.

Analysis of Sequential Adsorption–Oxidation of VOCs on Atomic Layer-Deposited PtNi/ZrO2–SiO2 Dual-Function Materials

To develop efficient dual-function materials (DFMs) for capture and destruction of volatile organic compounds (VOCs), we prepared a series of composite materials comprising PtNi nanoparticles supported on ZrO2-promoted SiO2 (PtNi/ZrO2–SiO2) via atomic layer deposition (ALD) method and investigated them for sequential adsorption and desorption/catalytic oxidation of benzene, as a model VOC compound. ZrO2 was first deposited on a unimodal SiO2 support, followed by deposition of Pt and Ni nanoparticles with varried amount. Dynamic adsorption experiments were conducted using a 500 ppmv-laden feed at 25 °C and 1 atm, followed by in situ catalytic oxidation at 200 °C. Among the DFMs investigated, 1Pt2Ni/ZrSi emerged as the material with overall in situ conversion of ∼96% due to its retaively high PtNi acid sites density compared with other DFMs. Kinetic analysis was conducted on 1Pt2Ni/ZrSi by investigating the effects of feed concentration, regenerative feed flow rate, and oxidation temperature on the benzene conversion in the sequential adsorption–oxidation process. The results of the kinetic analysis revealed that a complete oxidation can be attained over 1Pt2Ni/ZrSi and its performance can be improved upon decreasing adsorptive feed benzene concentration (maximum value of 99.7% at 125 ppmv) and regenerative feed flow rate (100% at 5 mL/min), and increasing oxidation temperature (100% at 200 °C). Overall, the obtained results highlighted the optimal operation conditions for sequential adsorption and oxidation of VOCs over ALD-based DFMs.

Realizing Fast Synthesis of High‐Silica Zeolite Y with Remarkable Catalytic Performance

AbstractHigh‐silica zeolite Y (FAU) plays a vital role in (petro)chemical industries. However, the slow nucleation and growth kinetics of the high‐silica FAU framework limit its direct synthesis and the improvement of framework SiO2/Al2O3 ratio (SAR). Here, a facile strategy is developed to realize the fast crystallization of high‐silica zeolite Y, which involves the combination of high crystallization temperature, ultra‐stable Y (USY) seeds and efficient organic‐structure directing agent (OSDA). The synthesis can be finished in 5–16 h at 160 °C and with tunable SAR up to 18.2, and the key factors affecting crystallization kinetics and phase purity are elucidated. Moreover, the crystallization process was monitored to reveal the fast crystal growth mechanism. The high‐silica products possess high (hydro)thermal stability and abundant strong acid sites, which endow them excellent catalytic cracking performance, obviously superior to commercial USY.

Realizing Fast Synthesis of High-Silica Zeolite Y with Remarkable Catalytic Performance.

High-silica zeolite Y (FAU) plays a vital role in (petro)chemical industries. However, the slow nucleation and growth kinetics of the high-silica FAU framework limit its direct synthesis and the improvement of framework SiO2 /Al2 O3 ratio (SAR). Here, a facile strategy is developed to realize the fast crystallization of high-silica zeolite Y, which involves the combination of high crystallization temperature, ultra-stable Y (USY) seeds and efficient organic-structure directing agent (OSDA). The synthesis can be finished in 5-16 h at 160 °C and with tunable SAR up to 18.2, and the key factors affecting crystallization kinetics and phase purity are elucidated. Moreover, the crystallization process was monitored to reveal the fast crystal growth mechanism. The high-silica products possess high (hydro)thermal stability and abundant strong acid sites, which endow them excellent catalytic cracking performance, obviously superior to commercial USY.

Effect of Indium Addition on the Low-Temperature Selective Catalytic Reduction of NO x by NH3 over MnCeO x Catalysts: The Promotion Effect and Mechanism.

A MnCeInOx catalyst was prepared by a coprecipitation method for denitrification of NH3-SCR (selective catalytic reduction). The catalysts were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry, scanning electron microscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller analysis, H2 temperature-programmed reduction, and NH3 temperature-programmed desorption. The NH3-SCR activity and H2O and SO2 resistance of the catalysts were evaluated. The test results showed that the SCR and water resistance and sulfur resistance were good in the range of 125–225 °C. The calcination temperature of the Mn6Ce0.3In0.7Ox catalyst preparation was studied. The crystallization of the Mn6Ce0.3In0.7Ox catalyst was poor when calcined at 300 °C; however, the crystallization is excessive at a 500 °C calcination temperature. The influence of space velocity on the performance of the catalyst is great at 100–225 °C. FTIR test results showed that indium distribution on the surface of the catalyst reduced the content of sulfate on the surface, protected the acidic site of MnCe, and improved the sulfur resistance of the catalyst. The excellent performance of the Mn6Ce0.3In0.7Ox catalyst may be due to its high content of Mn4+, surface adsorbed oxygen species, high specific surface area, redox sites and acid sites on the surface, high turnover frequency, and low apparent activation energy.

Optimal Conditions for Butanol Production from Ethanol over MgAlO Catalyst Derived from Mg-Al Layer Double Hydroxides.

The MgAlO catalyst was obtained from thermal decomposition of the MgAl-LDH catalyst having Mg/Al molar ratio of 5. The catalytic Guerbet reaction of ethanol was investigated to determine the effect of WHSV and nitrogen flow rate on butanol production and product distribution. It was performed in a fixed-bed microreactor under continuous flow of vaporized ethanol mixed with N2. The MgAlO catalyst had high total basic sites and high total acid sites that were crucial for ethanol Guerbet reaction. The MgAlO catalyst showed the highest butanol selectivity at 300℃ under WHSV = 3.10 h-1 and nitrogen flow rate = 3,600 mL/h, and the highest butanol yield at 400℃ under WHSV = 3.10 h-1 and nitrogen flow rate = 900 mL/h. It can be summarized that in order to enhance the butanol yield, the low WHSV is preferred to increase the contact time of ethanol and catalyst under moderate temperature.

Assessment on the Effect of Sulfuric Acid Concentration on Physicochemical Properties of Sulfated-Titania Catalyst and Glycerol Acetylation Performance

In this research, a solid acid catalyst was synthesized to catalyse glycerol acetylation into acetins. The sulphated-titania catalysts were prepared via the wet impregnation method at different sulfuric acid concentrations (5%, 10%, 15%, and 20%) and denoted as 5SA, 10SA, 15SA, and 20SA, respectively. The synthesized catalysts were characterized using FTIR, XRD, TGA, BET, NH3-TPD, XRF, and SEM-EDX. The synthesized catalysts were tested on glycerol acetylation reaction at conditions: 0.5 g catalyst loading, 100–120 °C temperature, 1:6 glycerol/acetic acid molar ratios, and 2–4 h reaction time. The final product obtained was analysed using GC-FID. An increment in sulfuric acid concentration reduces the surface area, pore volume, and particles size. However, the increment has increased the number of active sites (Lewis acid) and strong acid strength. 15SA catalyst exhibited excellent glycerol conversion (&gt;90%) and the highest selectivity of triacetin (42%). Besides sufficient surface area (1.9 m2 g−1) and good porosity structure, the great performance of the 15SA catalyst was attributed to its high acid site density (342.6 µmol g−1) and the high active site of metal oxide (95%).

Study on using cellulose derivatives as pore directing agent for preparation of hierarchical ZSM-5 zeolite catalyst

Cellulose derivatives such as hydroxyethylmethylcellulose (HEMC), and hydroxypropylmethylcellulose (HPMC), which are originated from biomass, were used as mesoporous directing agent for the synthesis of hierarchical ZSM-5 zeolite. Hierarchical ZSM-5 zeolites with outstanding mesoporosity and high hierarchy factors were achieved by hydrothermal method in the presence of bio-mesoporogen. The as-synthesized hierarchical ZSM-5 zeolites were characterized by X-ray diffraction (XRD), nitrogen adsorption–desorption (BET), scanning electron microscope (SEM) to determine the structure of samples. The influences of different mesoporogens with different dosage in the synthetic process on the physicochemical and catalytic properties of hierarchical ZSM-5 zeolite were investigated. Possession of the high mesopores, high surface areas and abundant accessible acid sites, the hierarchical zeolites exhibited excellent catalytic performance in the alkylation reaction of benzene and benzyl alcohol.

A Carbon‐Based Solid Acid Catalyst Prepared through a One‐Step Hydrothermal Carbonization: Efficient Catalysts for Liquid‐Phase Nitrification

AbstractCarbon‐based solid acid catalysts were successfully prepared by hydrothermal carbonization method and one‐pot method using naphthalene crosslinked by formaldehyde and sulfonated by H2SO4 (98 %). The characterization results showed that the catalysts prepared by hydrothermal carbonization method had more amorphous carbon composed of aromatic carbon sheets with functional groups (−SO3H, −COOH and −OH) than the catalyst prepared by one‐pot method. The preparation conditions of hydrothermal carbonization method were optimized. The F−N−SO3H‐h‐2.49 (1 : 11) prepared under optimal conditions showed high conversion of cyclohexane (48.2 %) and selectivity to nitrocyclohexan (98.2 %) at 125 °C for liquid‐phase nitrification, attributed to high acid site density (3.08 mmol/g) and amorphous carbon structure with hydrophilic functional groups. The F−N−SO3H‐h‐2.49 (1 : 11) also showed excellent thermal stability until 460 °C. The thermal stability of the catalyst is due to mutual electron‐withdrawal of aromatic carbon sheets.