Catalyst In Aqueous Solution Research Articles

Electrocatalytic Hydrogenation and Deuteration of Unsaturated C-N Bonds to Amines with Vacancy-rich Cu3P Nanowires as Catalysts in Aqueous Solution.

Renewable energy driven electrochemically hydrogenation of unsaturated C-N bonds with water as a hydrogen source provides an eco-friendly route for amine production. However, the potential commercial applications of this strategy were limited by the lack of relevant extended research. Here we demonstrate an efficient electrochemical hydrogenation system for the formation of amines from nitriles by a vacancy-rich copper phosphide catalyst. The catalytic system achieves a yield of 99% and a Faraday efficiency of 99% for the hydrogenation of benzonitrile. Mechanism study shows that benzonitrile is spontaneously adsorbed on the electrode surface and the electrogenerated active adsorbed hydrogen is the key reactive intermediate for hydrogenation. Theoretical calculation results show that vacancy-induced active sites chemisorb the N atom, thus accelerating C≡N bond activation for hydrogenation. Encouragingly, good yields of amines (≥99%) are obtained when benzonitrile is replaced by a series of aromatic nitriles, heterocyclic nitriles, aliphatic nitriles, and imines. These results show the general applicability of this method for the synthesis of various amines.

Visible light induced S-scheme charge transfer mechanism from Bi12TiO20 to CsPbBr3 for photodegradation of organic pollutants in aqueous solution

This work describes the formation of CsPbBr3/Bi12TiO20 S-scheme heterojunction photocatalysts using 3-mercaptopropionic acid (MPA) passivated CsPbBr3 nanocrystals (CPB) combined with Bi12TiO20 (BTO) nanorods. Under illumination, the charge carriers—undergo a process known as the S-scheme charge transfer, which significantly enhances their redox capability. The most efficient photodegradation of Rhodamine B (RhB) was recorded with the fine-tuned 10%CPB/BTO composite (degradation rate of 95.35% within 50 min, kapp = 0.06202 min−1). This improvement is primarily due to the MPA passivation, which increases the stability of the catalyst in aqueous solutions, and the S-scheme heterojunction design, which improves carrier separation and utilisation efficiency.

In-situ immobilization strategy for single-atom iron sites to enhance oxygen reduction reaction in Zn–air batteries and microbial fuel cells

A straightforward and environmentally friendly approach was utilized to synthesize single-atomic Fe–N–C catalyst. In-situ immobilization of Fe3+ during the formation of polydopamine (PDA) and ZIF-8 in aqueous solution effectively prevent metal agglomeration. The mutual promotion of PDA and aqueous solution constructed the hybrid-level porous hollow structure in P–FeNC. This method extends the solution scope from organic solution system to water solution, thus providing fascinating opportunities for investigating metal-N-C catalyst by in-situ mixing various metal salt precursor and dopamine. The optimal P–FeNC catalyst demonstrates superlative oxygen reduction reaction (ORR) performance, with the half-wave potentials (E1/2) of 0.886 V, 0.79 V, and 0.72 V in 0.1 M KOH, 0.5 M H2SO4, and 0.05 M PBS solutions, which exceeded commercial 20 wt% Pt/C. The combinatorial impacts of highly dense FeN4 active sites and interconnected hierarchical mesopores/macropores are presumed to underpin the observed enhancement in ORR performance. Further evaluations show that the power densities of P–FeNC equipped zinc-air battery (ZAB) and microbial fuel cell (MFC) are 460 mW/cm2 and 3083 ± 10 mW/m2, respectively. This study confirms the feasibility to design the innovative single-atom catalyst in aqueous solution and provides constructive ideas to employ the high-performance P–FeNC electrocatalyst in ZABs and MFCs.

Process for desulfurization and demineralization of low rank coal using oxidation assisted froth floatation technique

This study reports the desulfurization and deashing of Hangu coal by air oxidation assisted froth floatation technique applying performic acid (H2O2+HCOOH) as co-oxidant and Fe ions as catalysts in aqueous solution. This process led to the removal of up to 78.08% of total sulfur (TS) and 50.3% of ash at 60 °C, 30 min, a 2:2 ratio of H2O2+HCOOH (v/v), and 0.10% of Fe ions concentration. The sulfur and ash removal followed Fenton mechanism, wherein hydrogen peroxide (H2O2) dissociated into hydroxyl ions (OH-) and hydroxyl radicals (OH.), facilitated by the dissociation of ferrous ions (Fe2+). The reaction of HCOOH with OH. resulted in the formation of performic acid or peroxyl radical, selectively oxidizing sulfur compounds to sulfone and sulfoxide. In the subsequent phase, coal froth floatation was employed with the addition of surfactant i.e. Triton X-100 (TX-100) and collector i.e. diesel oil (DO), resulting in the removal of up to 49.83% of TS and 43.79% of ash. This was achieved under optimized conditions, specifically with a concentration of 400 ppm solution of TX-100 in the solution and a volume of 0.2 mL for DO. The emulsion of TX-100 and DO for the floatation of coal is a suitable option because TX-100 established polar interactions and hydrogen bonding with the oxidized functionalities of coal, whereas the hydrocarbons of diesel oil get attached to the unoxidized coal matrix through hydrophobic interaction. Onwards, simultaneous oxidation assisted by froth floatation in a two-step batch process at pre-optimized parameters resulted in TS and ash removal of 88.8% and 82.6%, and 62.2% and 39.3% in the froth and tailings, respectively. SEM, FTIR and XRD analyses revealed structural and morphological changes, modifications in chemical functionalities and mineralogical changes in the coal sample. The process can be scaled up for the up-gradation of low grade coal for industrial and power generation purposes.

RATE AND SELECTIVITY OF HYDROGENATION OF 2-NITRO-2'-HYDROXY-5'-METHYLAZOBENZE OVER NICKEL CATALYST IN AQUEOUS SOLUTIONS OF ALIPHATIC ALCOHOLS

Elucidation of the causes and character of the composition and nature solvent influence on the kinetic regularities and selectivity of hydrogenation reactions of compounds containing several reactive groups is of theoretical and practical significance. In the present work, the process of 2-nitro-2'-hydroxy-5'-methylazobenzene catalytic hydrogenation in the liquid phase is considered in order to obtain the corresponding benzotriazole, an effective UV stabilizer of polymeric materials. The process was carried out on a skeletal nickel catalyst in aqueous solutions with different contents of aliphatic alcohols, both at atmospheric and elevated hydrogen pressures. It has been experimentally established that the shape of the hydrogenation kinetic curves is determined by the composition of the water-alcohol solvent and is transformed from the dependence with a maximum in media with low alcohol content to the stepped curve in concentrated solutions. The dependences of the reaction rate on the content of aliphatic alcohol are complex, and the maximum hydrogenation rates are observed in solvents with a content 0.6÷0.7 ppm. of alcohol. The change in the process rate is associated with a change in the solubility, value of adsorption and reactivity of the starting compound and hydrogen. These factors also determine the selectivity of the process due to their influence on the rates of individual steps in the 2-nitro-2'-hydroxy-5'-methylazobenzene conversion scheme, in particular, on the cyclization rate of the associative surface complex "nitroazobenzene∙H2". The cyclization product of the complex is an intermediate compound, benzotriazole N-oxide, the reduction of which leads to the formation of a substituted benzotriazole. It is shown that the maximum yield of the target product is 48÷3% at atmospheric hydrogen pressure, and increases to 73.5-0.5% at PН2 = 1 MPa.

Observation of surface morphology of carbon alloy catalysts in aqueous solution by atomic force microscopy

Observation of surface morphology of carbon alloy catalysts in aqueous solution by atomic force microscopy

Polyfluoroalkyl Chain-Based Assemblies for Biomimetic Catalysis.

Amphiphobic fluoroalkyl chains are exploited for creating robust and diverse self-assembled biomimetic catalysts. Long terminal perfluoroalkyl chains (Cn F2n+1 with n=6, 8, and 10) linked with a short perhydroalkyl chains (Cm H2m with m=2 and 3) were used to synthesize several 1,4,7-triazacyclononane (TACN) derivatives, Cn F2n+1 -Cm H2m -TACN. In the presence of an equimolar amount of Zn2+ ions that coordinate the TACN moiety and drive the self-assembly into micelle-like aggregates, the critical aggregation concentration of polyfluorinated Cn F2n+1 -Cm H2m -TACN⋅Zn2+ was lowered by ∼1 order of magnitude compared to the traditional perhyroalkyl counterpart with identical carbon number of alkyl chain. When 2'-hydroxypropyl-4-nitrophenyl phosphate was used as the model phosphate substrate, polyfluorinated Cn F2n+1 -Cm H2m -TACN⋅Zn2+ assemblies showed higher affinity and catalytic activity, compared to its perhyroalkyl chain-based counterpart. Coarse-grained molecular dynamic simulations have been introduced to explore the supramolecular assembly of polyfluoroalkyl chains in the presence of Zn2+ ions and to better understand their enhanced catalytic activity.

Construction of imidazole@defective hierarchical porous UiO-66 and fibrous composites for rapid and nonbuffered catalytic hydrolysis of organophosphorus nerve agents

Hydrolytic destruction of toxic organophosphorus nerve agents by metal-organic framework (MOF) catalysts is commonly reliant on bulk water and volatile liquid base, preventing real-world implementation. Poor accessibility to MOF-based active sites in heterogeneous catalysis is also a crucial factor since reactants diffusion is limited by inherently small micropores. To overcome these practical limitations, a ligand-selective pyrolysis strategy was used to construct unsaturated Zr defects and additional mesopores in UiO-66(Zr). Owing to synergistic effect of Zr defects and hierarchical pores, hydrolysis rate constant (k) of nerve agent simulant DMNP (dimethyl 4-nitrophenyl phosphate) on optimal DHP-UiO-30% (defective hierarchical porous UiO-66) is 3.2 times higher than counterpart UiO-30% in N-ethylmorpholine buffer. Encapsulating imidazole (Im) into DHP-UiO-30% affords Im@DHP-UiO, mimicking phosphotriesterase. Im-72@DHP-UiO exhibits rapid DMNP detoxification with 99% conversion in 12 min and initial half-life (t1/2) of 1.8 min in nonbuffered water. As the first example of ‘three-in-one’ detoxifier, Im@DHP-UiO is further integrated onto nonwoven fabric to construct Im@DHP/Fiber, achieving solid-phase detoxification at ambient humidity with t1/2 of 19.6 min and final conversion of 91%. This is comparable to many powdered catalysts in aqueous solution buffered by volatile bases. This unified strategy is critical and viable to efficiently hydrolyze nerve agents in practical settings.

Novel preparation of MOF derived Co(OH)2/ZnFe2O4 magnetic micro-nanoreactor with boost peroxymonosulfate activation for enhanced antibiotic contaminant oxidation

Development of highly efficient and recyclable catalysts based on peroxymonosate (PMS) activation for the degradation of dangerous antibiotic contaminants was still a challenging topic. In this study, a highly efficient and recyclable heterogeneous Co(OH)2/ZnFe2O4 (Co-ZF) catalysts derived from metal-organic frameworks (MOFs) were prepared by a facile alkaline solution hydrothermal method, a high specific surface area (100.4 m2 g−1) and soft magnetic properties (Ms=25.3 emu g−1) composite material was obtained, and used for degrading norfloxacin (NOF) via PMS activation. The effects of temperature, alkali concentration, pH, initial NOF concentration, PMS and catalyst dosage on NOF degradation were discussed in detail. The results illustrated that the degradation rate of norfloxacin by the 3Co-ZF160 catalyst synthesized under 3 M NaOH and 160 ℃ hydrothermal conditions was 97.2%, after four consecutive cycles of degradation, the degradation rate of NOF by 3Co-ZF160 remained over 91% within 60 min. In contrast, the degradation rate of the Co3O4/ZnFe2O4 (CZF-600) catalyst calcined at 600 ℃ was only 74% available. Furthermore, The results of radical quenching suggested that OH•, SO4•−, SO5•− and 1O2 functioned in the presence of the Co(OH)2/ZnFe2O4-PMS system. Eventually, NOF degradation pathways were tentatively proposed on the basis presented via LC-MS. The above results highlight that the practical application of Co(OH)2/ZnFe2O4 heterogeneous catalyst in aqueous solution was of great significance.

Synthesis of calcium lactate starting from glycerol and calcium hydroxide catalyzed by copper-based catalysts in aqueous solution

The direct synthesis of calcium lactate starting from glycerol and calcium hydroxide in an aqueous solution catalyzed by hydroxyapatite nanorod (HA)-, titanate nanowhisker-, and activated carbon (C)-supported metallic copper catalysts was investigated. The selectivity of calcium lactate was above 91% at the glycerol conversions of 92–––95% when the reaction was catalyzed by Cu(16)/HA catalyst in an aqueous solution with a Ca(OH)2/glycerol molar ratio of 0.6:1.0 at 230 °C for 2–––4 h. The Cu/HA catalyst with a higher alkalinity and a smaller copper particle size exhibited higher catalytic activity in the synthesis of calcium lactate starting from glycerol and Ca(OH)2 than the Cu/titanate and Cu/C catalysts. The reaction kinetics simulation shows that the activation energy on the Cu(16)/HA catalyst is 43.85 kJ·mol−1. When calcium lactate was separated from reaction mixture by the concentrated crystallization method, the yield of calcium lactate was up to 87.9% with the purity of 95.5%.

A Polymeric Unimolecular CO Dehydrogenase Mimic with both Inner and Outer Spheres for Enhanced Photocatalytic CO2 Reduction in Aqueous Solution.

Inspired by carbon monoxide dehydrogenase (CODH), mimicking its inner and outer spheres is a promising strategy in CO2 reduction catalyst design. However, artificialCODH-like catalysts are generally limited to the inner sphere effect and only applicable in organic solvents or for electrocatalysis. Herein, we report an aqueous CODH mimic with both inner and outer spheres for photocatalysis. In this polymeric unimolecular catalyst, the inner sphere is composed of cobalt porphyrin with four appended amido groups and the outer sphere consists of four poly(2(dimethylamino)ethyl methacrylate) (PDMAEMA) arms. Upon visible light irradiation (λ > 420 nm), the as-prepared photocatalyst exhibits a high turnover number (TONCO = 1731.2) in the reduction of CO2 into CO, which is superior to most reported molecular photocatalysts in aqueous solution. The mechanism studies indicate that, in this water-dispersible and structurally well-defined CODH mimic, the cobalt porphyrin core serves as the catalysis center, amido groups function as hydrogen-bonding pillars helping to stabilize the CO2 adduct intermediate, while PDMAEMA shell renders both the water solubility and a CO2 reservoir through reversibly capturing of CO2. The present work has clarified the significance of inner and outer coordination sphere effects for improving the aqueous photocatalytic CO2 reduction performance of CODH mimics.

Comproportionation of CO2 and Cellulose to Formate Using a Floating Semiconductor-Enzyme Photoreforming Catalyst.

Formate production via both CO2 reduction and cellulose oxidation in a solar-driven process is achieved by a semi-artificial biohybrid photocatalyst consisting of immobilized formate dehydrogenase on titanium dioxide (TiO2 |FDH) producing up to 1.16±0.04 mmolformate g -1 in 24 hours at 30 °C and 101 kPa under anaerobic conditions. Isotopic labeling experiments with 13 C-labeled substrates support the mechanism of stoichiometric formate formation through both redox half-reactions. TiO2 |FDH was further immobilized on hollow glass microspheres to perform more practical floating photoreforming allowing vertical solar light illumination with optimal light exposure of the photocatalyst to real sunlight. Enzymatic cellulose depolymerization coupled to the floating photoreforming catalyst generates 0.36±0.04 mmolformate per m2 irradiation area after 24 hours. This work demonstrates the synergistic solar-driven valorization of solid and gaseous waste streams using a biohybrid photoreforming catalyst in aqueous solution and will thus provide inspiration for the development of future semi-artificial waste-to-chemical conversion strategies.

Comproportionation of CO2 and Cellulose to Formate Using a Floating Semiconductor‐Enzyme Photoreforming Catalyst

AbstractFormate production via both CO2 reduction and cellulose oxidation in a solar‐driven process is achieved by a semi‐artificial biohybrid photocatalyst consisting of immobilized formate dehydrogenase on titanium dioxide (TiO2|FDH) producing up to 1.16±0.04 mmolformate g −1 in 24 hours at 30 °C and 101 kPa under anaerobic conditions. Isotopic labeling experiments with 13C‐labeled substrates support the mechanism of stoichiometric formate formation through both redox half‐reactions. TiO2|FDH was further immobilized on hollow glass microspheres to perform more practical floating photoreforming allowing vertical solar light illumination with optimal light exposure of the photocatalyst to real sunlight. Enzymatic cellulose depolymerization coupled to the floating photoreforming catalyst generates 0.36±0.04 mmolformate per m2 irradiation area after 24 hours. This work demonstrates the synergistic solar‐driven valorization of solid and gaseous waste streams using a biohybrid photoreforming catalyst in aqueous solution and will thus provide inspiration for the development of future semi‐artificial waste‐to‐chemical conversion strategies.

Activating Bi p‐orbitals in Dispersed Clusters of Amorphous BiOx for Electrocatalytic Nitrogen Reduction

AbstractCatalytic strategies based on main group metals are significantly less advanced than those of transition metal catalysis, leaving untapped areas of potentially fruitful research. We here demonstrate an effective approach for the modulation of Bi 6p energy levels during the construction of atomically dispersed clusters of amorphous BiOx. Bi oxidation state is proposed to strongly affects the nitrogen fixation activity, with the half‐occupied pz orbitals of the Bi2+ ions being highly efficient toward electron injection into the inert N2 molecule. With sufficient catalytic sites to adsorb and activate N2, the bonding between N2 and catalyst is able to be in situ identified. The catalyst shows an outstanding Faraday efficiency (≈30 %) and high yield (≈113 μg h−1 mg−1cat) in NH3 production, outperforming most of the existing catalysts in aqueous solution. These results lay the basis for developing the potential of p‐block elements for catalysis of multi‐electron reactions.

Activating Bi p-orbitals in Dispersed Clusters of Amorphous BiOx for Electrocatalytic Nitrogen Reduction.

Catalytic strategies based on main group metals are significantly less advanced than those of transition metal catalysis, leaving untapped areas of potentially fruitful research. We here demonstrate an effective approach for the modulation of Bi 6p energy levels during the construction of atomically dispersed clusters of amorphous BiOx . Bi oxidation state is proposed to strongly affects the nitrogen fixation activity, with the half-occupied pz orbitals of the Bi2+ ions being highly efficient toward electron injection into the inert N2 molecule. With sufficient catalytic sites to adsorb and activate N2 , the bonding between N2 and catalyst is able to be in situ identified. The catalyst shows an outstanding Faraday efficiency (≈30 %) and high yield (≈113 μg h-1 mg-1 cat ) in NH3 production, outperforming most of the existing catalysts in aqueous solution. These results lay the basis for developing the potential of p-block elements for catalysis of multi-electron reactions.

Novel magnetic catalysts for organic pollutant degradation via contact electro-catalysis

Contact-electro-catalysis (CEC) has been proposed as an efficient mechanism for organic pollutant degradation. However, the effects of chemical and physical properties of catalysts on the CEC efficiency have not been reported so far. Importantly, solving the secondary pollution caused by micro-nano catalysts due to the difficulty of recycling and inability to degrade is another bottleneck for achieving the commercial application of CEC. In this work, we synthesized a micro-nano catalyst with tunable chemical groups on the surface based on magnetic nanoparticles for the degradation of methyl orange (MO) via CEC. With the increase of the electronegativity of the chemical groups (R-F>R-CH3 >R-NH2), the degradation efficiency of MO also be improved obviously. The low surface energy of hydrophobic particles leads to the existence of a threshold (e.g., 20 mg R-F per 50 ml MO solution) for the exposed total surface area of the catalyst in aqueous solution, which is the main reason for the nonlinear increase of catalyst mass and CEC efficiency. Previously reported toxic non-degradable fluoride catalysts (e.g., FEP, PTFE) can be effectively replaced by catalysts R-CH3. Using the R-CH3 in CEC, the degradation efficiency of MO reaches 99% within 2 h. The micro-nano R-CH3 catalyst can be recycled by nearly 100% through the magnetic separator, and the catalytic efficiency can reach more than 97% after ten cycles of CEC. We expect this attractive catalyst to be a promising candidate for applications in large-scale organic pollutant degradation systems although more work on system parameter optimization needs to be further addressed.

Polymer Hydrogel Supported Ni/Pd Alloys for Hydrogen Gas Production from Hydrolysis of Dimethylamine Borane with a Long Recyclable Lifetime.

Hydrogen gas production can be produced from dimethylamine borane by the catalytic effect of metal nanoparticles. Past research efforts were heavily focused on dehydrogenation in organic solvents. In this study, hydrolysis of the borane in aqueous solutions was investigated, which bears two significant advantages: that two-thirds of the hydrogen generated originate from water and that the hydrogen storage materials are non-flammable. Polymer hydrogels serve as good carriers for metal particles as catalysts in aqueous solutions. Kinetic analysis of hydrogen production was performed for Ni/Pd bimetallic nanoclusters dispersed in a polymer hydrogel with a 3-D network structure. The reaction catalyzed by the bimetallic nanoclusters has an activation energy of only 34.95 kJ/mol, considerably lower than that by Ni or other metal catalysts reported. A significant synergistic effect was observed in the Ni/Pd bimetallic catalysts (Ni-Pd = 20/1) with a higher activity than Pd or Ni alone. This proves the alloy nature of the nanoparticles in the borane hydrolysis and the activation of water and borane by both metals to break the O-H and B-H bonds. The hydrogel with the Ni/Pd metal can be recycled with a much longer lifetime than all the previously prepared catalysts. The aqueous borane solutions with a polymer hydrogel can become a more sustainable hydrogen supplier for long-term use.

Magnetically-separable cobalt catalyst embedded in metal nitrate-promoted hierarchically porous N-doped carbon nanospheres for hydrodeoxygenation of lignin-derived species

The creation of non-noble metal magnetically-separable heterogeneous catalysts for the hydrodeoxygenation of biomass to value-added products has received substantial attention. Herein, we report a facile synthesis of magnetically-separable cobalt catalyst embedded in hierarchically porous N-doped carbon nanospheres (Co@NC) by in situ non-noble metal nitrate-promoted pyrolysis reduction strategy using nitrogen/oxygen co-doped resin polymer spheres as precursors. The facile H2O2 post-treatment process increased surface oxygen-containing groups and improved hydrophilicity to disperse catalysts in aqueous solutions. Moreover, owing to the non-noble metal nanoparticles coated with a graphitic nitrogen-doped carbon layer, the as-prepared Co@NCH2O2 catalyst exhibits excellent catalytic activity and stability of vanillin hydrodeoxygenation in aqueous solutions. This strategy can be extended to other non-noble metal nitrates like M@NCH2O2 (M = Co, Ni) within good recyclability, magnetically-separable ability, and general applicability for a broad substrate scope, further highlighting the superiority of our active catalysts.

Temperature-Controlled Selectivity of Hydrogenation and Hydrodeoxygenation of Biomass by Superhydrophilic Nitrogen/Oxygen Co-Doped Porous Carbon Nanosphere Supported Pd Nanoparticles.

Selective hydrogenation and hydrodeoxygenation (HDO) of biomass to value-added products play a crucial role in the development of renewable energy resources. However, achieving a temperature-controlled selectivity within one catalytic system while retaining excellent hydrogenation and HDO performance remains a great challenge. Here, nitrogen/oxygen (N/O) co-doped porous carbon nanosphere derived from resin polymer spheres is synthesized as the host matrix to in situ encapsulate highly dispersed Pd nanoparticles (NPs). Through N/O co-doping, the defects on the surface of carbon structure can serve as active sites to promote substrate adsorption. After a facile H2 O2 post-treatment process, the presence of abundant carboxyl groups on the porous carbon nanospheres can act as acidic sites to replace the use of acidic additives in the HDO process. Additionally, the increased surface oxygen-containing groups improve hydrophilicity to disperse catalysts in aqueous solutions. Owing to the unique highly dispersed Pd NPs and abundant surface defects, the Pd@APF-H2 O2 (2.3nm) catalysts exhibit excellent catalytic activity and temperature-controlled selectivity for hydrogenation and HDO products of biomass-derived vanillin.

Tin–chromium bimetallic metal–organic framework MIL-101 (Cr, Sn) as a catalyst for glucose conversion into HMF

5-hydroxymethylfurfural (HMF) is considered a promising platform chemical, from which numerous chemicals can be produced. Hence, developing an efficient catalytic system to convert glucose into HMF has drawn considerable attention. In this study, a series of Lewis acidic Sn–Cr bimetallic metal–organic frameworks, MIL-101(Cr, Sn), with different Sn ion loading were synthesized hydrothermally using acetic acid as the mineralizer and water as the solvent. The resulting MIL-101(Cr, Sn) was systematically analyzed as a catalyst for the conversion of sugar to HMF. Moreover, the effects exerted by various reaction parameters on HMF yield and selectivity were investigated. With glucose as the substrate and 0.5-wt% H2SO4 as a catalyst, an 85.75% glucose conversion with 22.64% HMF yield and 26.41% selectivity was achieved. Meanwhile, these parameters were improved via addition of MIL-101(Cr, Sn)-0.1. That is, glucose conversion, HMF yield, and selectivity were increased to 86.36%, 60.75%, and 70.35%, respectively, when using MIL-101(Cr, Sn)-0.1 and H2SO4 as the catalyst under the same reaction conditions. The MIL-101(Cr, Sn) structure enabled high stability of the catalyst in aqueous solutions with different pH values, while improving its thermal stability. Moreover, the catalyst could be reused several times despite a slight reduction in its catalytic activity. The current results illustrate that MIL-101(Cr, Sn) is an excellent acid and sustainable catalyst for the production of HMF from fructose, glucose, and starch.