Heteropolyacid Research Articles

Formic Acid Production via One-Pot Hydrolysis-Oxidation of Starch over Quaternary Ammonium Salts of Vanadium-Containing Keggin-Type Heteropoly Acids

Bifunctional solid acidic quaternary ammonium salts of Keggin-type vanadium-containing heteropoly acids, such as R3.5H0.5PVMo11O40 (R: (C2H5)4N, (C4H9)4N, (C6H13)4N), and [(C4H9)4N]4.5H0.5SiW11VO40, are capable of one-pot hydrolysis-oxidationconversion (OxFA-processing) of starch to biogenic formic acid. The impact of the reaction conditions and catalyst type was revealed. The highest formic acid yield of 50% was achieved over the best [(C2H5)4N]3.5H0.5PVMo11O40 catalyst, which was active and stable in seven reaction cycles. The kinetic computational model, which described formic acid formation well, was proposed in the presence of the most active [(C2H5)4N]3.5H0.5PVMo11O40 catalyst.

Durability and Performance Study of Chemically Anchored Heteropoly Acid with Perfluorinated Sulfonic Acid-Expanded Polytetrafluoroethylene Composite Membrane for Proton Exchange Membrane Fuel Cells

Chemical degradation and mechanical degradation are the major challenges for heavy-duty vehicle fuel cell commercialization. Perfluorinated sulfonic acid is the benchmark material that has high proton conductivity and robust mechanical properties. However, chemical degradation can occur through radical formation during the fuel cell operation. Chemical degradation can also have a synergetic effect with mechanical degradation. Recent studies have used cerium and manganese additives to suppress the radical formation or chemical degradation caused by radicals. The limitation of the metal and metal oxide additives was the migration and agglomeration of the additives. Both migration and clustering can lead to changes in membrane morphology, resulting in a loss in proton conductivity. Our group has previously reported that immobilization of heteropoly acid to a fluoroelastomer can be used to both enhance proton conductivity and chemical degradation. The durability test has shown that the chemical durability was significantly enhanced, but the mechanical durability remained the challenge.In this study, we hypothesized that when a heteropoly acid can be chemically bound to the perfluorinated polymer and cast on a composite membrane with expanded polytetrafluoroethylene (e-PTFE) will enhance the chemical and mechanical durability without migration. Proton conductivity was measured using impedance spectroscopy. The structure-property relationship was studied using multi-scale morphology analysis methods such as scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), and small-angle x-ray scattering (SAXS). The chemical degradation will be tested under the highly accelerated standard test (HAST) condition, a more severe fuel cell operation condition than the accelerated standard condition (AST). The mechanical durability of the composite membrane will also be tested on the HAST condition with humidity cycling.

Rational design of single tungsten/cobalt atom oxide anchored on the TiO2-rGO: A highly efficient electrocatalyst for water splitting and photocatalyst for decomposition of pharmaceutical pollutant

Single metal atom oxide catalysts (SMAOs) have impressive catalytic efficiency because they maximize the use of atoms, and their unique electronic structures in the reactions. We developed a single tungsten/cobalt atom oxide anchored on the TiO2-rGO catalyst (TPWCoR) from TiO2 P25-rGO and heteropoly acid with tungsten and cobalt. Electron microscope characterization showed that a significant amount of single tungsten/cobalt atom oxide (ST/CAO) was uniformly deposited on TiO2 P25 nanoparticle. The transition metal atoms are equally spread throughout on TiO2 P25-rGO material, according to aberration corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The hydrogen evolution reactions and oxygen evolution reactions (HER/OER) are crucial for electrochemical water splitting, and the TPWCoR nanocatalyst is extremely active and stable for these processes. The TPWCoR possessing a higher number of active sites, offers current densities of 10 mA cm−2 at 144 mV for HER and 10 mA cm−2 at 366 mV for OER in alkaline medium with a Tafel slope of 114.2 mV dec−1 (HER) and 62.6 mV dec−1 (OER), respectively. Superior cycling ability was also obtained throughout the alkaline HER and OER processes, showing its potential for use in real-world scenarios in the future. The simple synthetic strategy for producing efficient ST/CAO based HER and OER electrocatalysts for electrochemical water splitting presents a cost-effective approach. Additionally, the prepared TPWCoR nanocatalyst achieves around 96.87 % ciprofloxacin (CF) photodegradation after 60 min of UV irradiation. Analytical definitions of the best catalyst photodegradation processes may be made as variables of catalysts, dosage, and pH of the reaction media. All of these discoveries reveal novel understanding of how to construct low cost, reusable electro-photocatalysts with high water splitting and photodegradation efficiency.

Ionometric sensor for express determination of hexamethylenetetramine

The article is devoted to the development of an ionometric sensor for the determination of hexamethylenetetramine (HMTA). It was found that poorly soluble complex compounds with the composition (HMTA)3(PMo12O40)2 and (HMTA)3(PW12O40)2 are formed as a result of the interaction of the cation of the test substance with the anions of heteropoly acids. The obtained compounds were used as electrode active substances for polyvinyl chloride membranes of ionometric sensors. Phthalic acid derivatives (dibutyl and dioctyl phthalates) were used as solvents for plasticized membranes. The optimal composition of the membranes was established. The dependences of the electrochemical properties of the obtained sensor membranes on various factors were studied. This made it possible to choose the optimal conditions for the operation of the ionometric sensor. The response time of the sensor does not exceed 3 minutes, and the service life of the membrane (about 40 days) allows performing determination without replacement. The detection limit of hexamethylenetetramine using this sensor is 1.010–5 mol/l, and quantitative determination can be carried out in a fairly short time (5–10 min).

Design of γ-Alumina-Supported Phosphotungstic Acid-Palladium Bifunctional Catalyst for Catalytic Liquid-Phase Citral Hydrogenation

This study primarily addresses the development of dynamic, selective and economical metal–acid (bifunctional) catalysts for one-pot menthol production by citral hydrogenation. Specifically, various metals such as Pd, Pt, Ni, Cs and Sn were doped over alumina support. Additionally, bifunctional composite catalysts were also prepared with the impregnation of heteropoly acids and Pd precursors over alumina support. Analytical techniques (e.g., BET, PXRD, FT-IR, pyridine adsorption and amine titration methods) were applied for characterization of the most efficient and selective catalysts (e.g., Al2O3 and PTA-Cat-I). Similarly, most of the essential operational variables (e.g., loading rate of metal precursor, type of heteropoly acid, temperature, gas pressure and reaction time) were examined during this study. The experimental data shows that the bifunctional catalyst (PTA-Cat-I) produced 45% menthol at full citral substrate conversion (r = 0.038 mmoles.min−1) in liquid-phase citral hydrogenation (at optimized operating conditions: 70 °C, 0.5 MPa and 8 h). However, the heteropoly acid-supported bifunctional catalysts (e.g., PTA-Cat-I, PMA-Cat-I, SMA-Cat-I and STA-Cat-I) resulted in cracking and the dehydration of isopulegol/menthol by the generation of side products (e.g., 4-isopropyl-1-methyl, cyclohex-1-ane/ene); therefore, menthol yield was extensively diminished. On the other hand, non-acidic catalysts (e.g., Cat-I, Cat-II, Cat-III, Cat-IV and Cat-V) readily promoted hydrogenation reactions. The optimum menthol yield occurred due to the presence of strong Lewis and weak Bronsted acid sites. Mass transfer and reaction rate were substantially diminished due to acidity strength, heteropoly acid type and blockage of pores by the applied bifunctional catalysts.

Synthesis of energy rich fuel additive from biomass derived levulinic acid and furfuryl alcohol using novel tin-exchanged heteropoly acid supported on titania nanotubes as catalyst

Biomass feedstocks are available in a wide variety. It is an alternative source to fossil fuels to meet higher energy demand and a renewablefeedstock for many industrial products and chemical substances. Furfuryl alcohol and levulinic acid are both biomass-based chemicals that can be valorized for use in various applications. In the current study, we have introduced esterification reaction of furfuryl alcohol with levulinic acid to produce furan-2-ylmethyl 4-oxopentanoate, which can be used to synthesize biofuels, perfumes, flavouring agents, and other industrially useful compounds. For this conversion, a novel and highly efficient catalyst, 20 % (w/w) Sn metal exchanged dodecatungstophosphoric acid (TPA) with titania nanotubes (TNT) support was used under environmentally benign solventless reaction conditions. Partially substituted protons of TPA with Sn (x = 1) increased the acidity of the catalyst, and resulted into higher activity than 20 % (w/w) TPA/TNT. Protons of TPA were substituted with Sn metal at different proportions (i.e., H = 1, 2, 3 of TPA exchanged with Sn = 0.5, 1, 1.5, respectively). Amongst all, 20 % (w/w) Sn1-TPA/TNT was found to be the most efficient catalyst for the esterification reaction of furfuryl alcohol and levulinic acid due to its higher acidity. Fresh and reused catalysts were well-characterized using various analytical techniques. Using LHHW (Langmuir–Hinshelwood–Hougen–Watson) mechanism, a kinetic model was developed. The activation energy was found to be 7.85 and 13.58 kcal/mol for esterification (step 1) and self-etherification (step 2) reactions, respectively. The activation energy of esterification is lower than that of self-etherification and the rate of esterification is higher than that of self-etherification.

In situ generated micro-catalytic system for the epoxidation of allyl chloride with hydrogen peroxide

The epoxidation of allyl chloride and H2O2 catalyzed by heterogeneous catalyst suffers from inadequate mixing between organic phase, aqueous phase and solid catalyst. This work describes a novel micro-catalytic system for the intensification of this multiphase reaction process. Aqueous phase is capsulated with the loaded phosphotungsten heteropoly acid catalyst to produce microdroplets in situ, the oil-water interface consisting of the catalyst particles facilitates the epoxidation reaction. The regulation of microdroplet size can be achieved by changing the hydrophobicity of the catalyst surface, with a suitable hydrophobicity reducing the diameter of microdroplets and exhibiting optimal catalytic activity. The ECH conversion and selectivity in the micro-catalytic system can be reached as high as 98.02 % and 99 %, respectively. The structure and stability of the catalyst are illustrated by SEM, XPS, FT-IR and TGA. Furthermore, inexpensive commercial polystyrene was used as catalyst carriers, and the synthesis process of the catalyst is simple, which enables the large-scale synthesis of the catalyst. This strategy is a promising approach to designing catalysts for oil-water multiphase reactions.

Nanocomposites Use for the Creation of a Nanocomposite Fuel Cell Membrane in Advanced Hydrogen Technology

Development of high-impact base metal catalysts as an alternative to their platinum analogs in fuel cells for Oxygen Reduction Reaction (ORR) and Hydrogen Evolution Reaction (HER) is a desirable but extremely challenging task. Cutting-edge technology and improvements in nanocomposites open the way for use of nanocomposite-based membranes, which facilitate the hydrogen and oxygen reduction reaction to increase the stability of reactions in fuel cell at high temperatures but have drawbacks due to unstable conditions of the relative moisture level, which affects the change in nanocomposite properties. This paper focuses on research into CsPW-Nafion nanocomposite membrane with stable structure and properties for fuel cell applications for hydrogen production purposes. Rather low efficiency of membranes in hydrogen and oxygen evolution reactions in the fuel cell is a pressing problem, which requires alternative solutions in development of nanocomposite membranes to improve stability and conductivity properties. The findings of experimental research into the oxidation stability of nanocomposite membrane suggest that CsPW nanocomposite membrane has a high stability to oxidizing agents by reducing the diffusion of H2O2. Nanocomposite membrane has a fairly reliable performance at low relative humidity and high temperatures, which is due to compound with hydrophilic CsHP particles that tend to retain large amounts of water to maintain the membrane in a hydrated state. The authors were the first to suggest methodology for creating a nanocomposite cesium hydrogen salt membrane based on heteropoly acid with Nafion (CsPW-Nafion) for hydrogen technology fuel cell.

Effect of Different Supported Heteropoly Acid on the Catalytic Hydrothermal Conversion of Cellulose into Formic Acid

Cellulose, an abundant biomass, has received considerable attention as a renewable precursor to the formation of valuable chemicals. The overall strategy in this research is to produce formic acid from cellulose by using direct catalytic hydrothermal method. In this study, a heterogeneous catalyst system was developed by preparing different types of HPA on hydrotalcite. The three types of HPA- HT are phosphotungstic acid-hydrotalcite (PTA-HT), phosphomolybdic acid-hydrotalcite (PMA-HT) and silicotungstic acid-hydrotalcite (STA-HT); were prepared by the impregnation method. These prepared catalysts were characterized using FTIR, XRD and FESEM-EDX. The catalytic reaction was carried out in a hydrothermal reactor and the FA production was determined using HPLC-DAD. Comparison was made during the investigation where calcined HT was used for cellulose conversion and compared with each HPA-HT. All three catalysts were successfully impregnated on the calcined HT, as proven by XRD, FTIR, and EDX. According to the finding, PMA-HT give the highest cellulose conversion (48%) and FA yield (9.61%) followed by PTA-HT (32% converted cellulose with 7.35% FA yield) and STA-HT (17% cellulose converted and 2.87%). This phenomena occur due to the acidity and moderate redox properties of molybdenum in PMA. Herein, we reported effects of different HPAs on HT towards FA yield.

Effect of interfacial activity of quaternary ammonium cation on kinetics of epoxidation of allyl chloride with hydrogen peroxide

A series of quaternary ammonium phosphotungstic heteropoly acid catalysts with different carbon chain lengths [(CnH2n+1)2(CH3)2N]3{PO4[W(O)(O2)2]4} (n = 8, 10, 12, 14, 16) were synthesized for the epoxidation of allyl chloride with H2O2. The hydrophilic and hydrophobic structure of the catalysts were regulated to optimize the interfacial activity by changing the carbon chain lengths of the quaternary ammonium cations. The reaction system using catalyst [(C10H21)2(CH3)2N]3{PO4[W(O)(O2)2]4} showed the lowest interfacial tension between oil and water, the smallest particle size of emulsion droplets and the largest interfacial area, which resulted in the highest catalytic performance. The reaction kinetics and interface properties studies, including the activation energy, interfacial tension, and microscopic imaging of droplets, were conducted to provide strong proof. The epoxidation reaction rates were significantly associated with the surface activity of different carbon chain length catalysts and their effects on the allyl chloride-H2O2 interfacial properties.

Highly efficient heteropoly acid decorated SnO2@Co-ZIF nanocatalyst for sustainable biodiesel production from Nannorrhops ritchiana seeds oil

In this study, TPA-impregnated SnO2@Co-ZIF catalyst was synthesized to employ for biodiesel production from locally available Mazari palm feedstock. The morphological and structural properties of the synthesized catalyst were studied by different analytical techniques such as Thermal gravimetric analysis (TGA/DTA), X-Ray diffraction analysis (XRD), Scanning electron microscopy (SEM), Energy dispersive X-Ray (EDX) analysis, Fourier transform infrared spectroscopy (FT-IR), Brunauer Emmett Teller (BET) and Temperature Programmed Desorption of ammonia (NH3–TPD) and carbon dioxide (CO2–TPD) to identify suitable catalyst formulation for efficient biodiesel production from Mazari palm oil.The important variables such as molar ratio of alcohol to oil, reaction temperature, amount of catalyst, reaction time and agitation speed were also investigated to achieve best parameters setup for highest biodiesel yield. The results showed that the highest biodiesel yield of 94.05% was obtained at the 18:1 methanol to oil molar ratio, 100 °C reaction temperature, reaction time of 180 min, 5% catalyst dosage and agitation speed of 500 rpm. Moreover, the catalyst possesses high stability and can be recycled up to 5 consecutive biodiesel reactions without any loss in activity and additional treatment.

Preparation and photocatalytic properties of β2-SiW11Mn/TiO2 nanomaterials

With manganese substituted heteropoly tungstate β2-K6[SiW11Mn(H2O)O39]·xH2O as the active component, a composite photocatalyst β2-SiW11Mn/TiO2 was prepared by impregnation method. The composite catalyst was characterized by FT-IR, UV-Vis, XRD, SEM and X-ray photoelectron spectroscopy. The catalytic activity was evaluated by the degradation of malachite green solution. The results showed that the degradation of malachite green under ultraviolet light reached 92.7% and the degradation effect under sunlight is better than that under ultraviolet light, reaching 97.2%. This indicates that polyoxometalates and titanium dioxide produced a synergistic effect to make the light response range expanded and reduced the reaction requirements. The catalytic degradation performance of pure titanium dioxide, heteropoly acid salt β2-SiW11Mn and the prepared catalyst β2-SiW11Mn/TiO2 on malachite green were studied. The results showed that the composite photocatalyst exhibited the best photocatalytic activity, confirming the significance of the material being compounded. Finally, the kinetics of the reaction were studied, and the reaction is a first-order reaction.

Advances in novel activation methods to perform green organic synthesis using recyclable heteropolyacid catalysis

Abstract Highly functionalized, high value added bioactive molecules are generally obtained by synthetic procedures that are highly selective, economical, with high atom economy, and environmentally friendly. Following these guidelines, the use of recoverable solid catalysts, nonpolluting substrates, or toxic organic solvent contributes greatly to these demands. In the last three decades, heteropolyacids (HPAs) and its derivatives have received great attention as recyclable solid catalysts, due to their strong Brönsted acidity, excellent oxidizing capacity under mild conditions, and various reuse cycles without appreciable loss of their catalytic activity. However, new activation methods should be investigated to improve the sustainability of a process using HPAs. In this review, we report the latest advances associated with the synthesis of potentially bioactive molecules using more energy efficient alternatives such as microwaves, ultrasound, mechanochemistry, and photochemistry to minimize the energy consumption associated with organic synthesis. The transformations studied include construction reaction, heterocycle synthesis, selective oxidation, and biomass recovery.

Chemiluminescence based on UV-assisted persulfate activation for sensitive detection of triphenyl phosphate.

Triphenyl phosphate (TPHP), a typical kind of organophosphorus flame retardants (OPFRs) with aryl groups, has been recognized as an emerging contaminant that causes environmental and health hazards. It is a pervasive threat that can be frequently detected in the environment and living organisms. Hence, establishing an efficient analytical method for TPHP is an urgent issue. In this work, a heteropolyacid (HPA)-luminol chemiluminescence strategy coupled with UV-assisted persulfate (PS) activation was proposed for the sensitive and selective detection of TPHP. The UV-assisted PS oxidation pretreatment could decompose the water-insoluble TPHP into smaller orthophosphates, which were further converted into HPA with the subsequently introduced vanadium‑molybdenum acid. The formed HPA served as a catalyst to oxidize luminol, and strong chemiluminescence at 425 nm was generated immediately. Furthermore, the degradation process of TPHP and chemiluminescence mechanism were also investigated. The results demonstrated that some reactive oxygen radicals such as SO4-, OH, 1O2, and O2-, were involved in the degradation and chemiluminescence reaction. Notably, this proposed chemiluminescence analytical strategy realized a highly sensitive detection for TPHP, and granted the limit of detection down to 0.38 ppt. This study provides an attractive perspective for the detection of emerging OPFRs.

V-Containing Heteropoly Acids with Keggin Structure as Precursors of Sulfide Catalysts: Regularities of the Convertion of Dibenzothiophene and Naphthalene on Nonpromoted Mo–V Catalysts

Mixed PMoV heteropoly acids with Keggin structures H3+xPMo12–xVxO40 (x = 1–6) and modified sulfide catalysts on their basis were synthesized, their physicochemical characteristics were determined, and their performance in the reactions of hydrodesulfurization (HDS) of dibenzothiophene (DBT) and hydrogenation of naphthalene was evaluated. Modification of the Mo-containing catalysts with vanadium by impregnation with a solution of mixed heteropoly acids was found to enhance their catalytic activity in the studied reactions, as well as to increase the selectivity for the direct hydrodesulfurization route of the DBT HDS reaction.

Oxidation of Organic Sulfur Compounds in the Presence of Heteropoly Acids Immobilized on Mesoporous Silicates

Oxidation of Organic Sulfur Compounds in the Presence of Heteropoly Acids Immobilized on Mesoporous Silicates

Synthesis of heteropolyacid (HPA) functionalized graphitic carbon nitride as effective catalysts for converting polysaccharides into high-value chemicals

Using renewable biomass resources to replace fossil resources has been regarded as an effective way to restore and protect the natural environment. Cellulose as a polysaccharide exists in nature or environmental pollution control facilities in the production process. To recover and effectively transform cellulose or other polysaccharide substances into more valuable products, a series of heteropolyacid (HPA) functionalized graphitic carbon nitride (g-C3N4) HPA/g-C3N4 (n wt%) was synthesized, which was evaluated their catalytic performance in the conversion of polysaccharides as cellobiose, sucrose, starch, and cellulose. The high yield (58.6%) of 5-hydroxymethylfurfural (5-HMF) was obtained in one-pot upon H3PW12O40(HPW)/g-C3N4(30) at 100% cellulose conversion, which was contributed to the nature of HPW/g-C3N4(30). HPW/g-C3N4 was determined as an efficient, recyclable solid catalyst with high stability and long duration for high selectivity to 5-HMF in one-pot. The design of novel HPA with the functionalized candidate will be necessary for polysaccharides hydrolysis to selectively obtain high-value products.

Comparative Catalytic Performance Study of 12-Tungstophosphoric Heteropoly Acid Supported on Mesoporous Supports for Biodiesel Production from Unrefined Green Seed Canola Oil

In this study, three solid acid catalysts, namely mesoporous aluminophosphate-supported 12-tungstophosphoric heteropoly acid (HPW/MAP), mesoporous aluminosilicate-supported 12-tungstophosphoric heteropoly acid (HPW/MAS), and gamma alumina-supported 12-tungstophosphoric heteropoly acid (HPW/γ-Al2O3) were prepared and characterized. Mesoporous aluminophosphate (MAP) and mesoporous aluminosilicate (MAS) were synthesized via sol-gel and hydrothermal methods, respectively, and 25 wt.% of 12-tungstophosphoric heteropoly acid (HPW) was immobilized on the support materials using the wet impregnation method. The features of the fabricated catalysts were comprehensively investigated using various techniques such as BET, XRD, NH3-TPD, TGA, and TEM. The surface area of the supported catalysts decreased after HPW impregnation according to BET results, which indicates that HPW loaded on the supports and inside of their pores successfully. The density and strengths of the acid sites of the support materials and the catalysts before reaction and after regeneration were determined by the NH3-TPD technique. Accordingly, an increase in acidity was observed after HPW immobilization on all the support materials. The catalytic performance of the catalysts was studied through alcoholysis reaction using unrefined green seed canola oil as the feedstock. The maximum biodiesel yield of 82.3% was obtained using 3 wt.% of HPW/MAS, with a methanol to oil molar ratio of 20:1, at 200 °C and 4 MPa over 7 h. The reusability study of HPW/MAS showed that it can maintain 80% of its initial activity after five runs.

Electrocatalytic oxidation of toluene into benzaldehyde based on molecular oxygen activation over oxygen vacancy of heteropoly acid

Benzaldehyde is much easier to be oxidized with respect to toluene, making the selective oxidation of toluene to benzaldehyde extremely challenging. Herein, a series of heteropoly acid catalysts with different ratios of molybdenum and vanadium supported on carbon paper (CP) were synthesized. The oxygen vacancy concentration and dispersion of heteropoly acid on CP can be changed by regulating the ratio of molybdenum and vanadium. Due to the suitable oxygen vacancy concentration and most uniform dispersion on CP, HPMoV2 has the highest electrocatalytic oxidation performance, showing the benzaldehyde selectivity of 83.5% at the toluene conversion of 83.4%. In-situ Raman spectroscopy proved that toluene was initially activated into benzyl cation and further oxidized by active oxygen species (O22-ads, O2-ads) to form benzaldehyde. The active oxygen species generated by electro-activation of molecular oxygen adsorbed on oxygen vacancies of heteropoly acid, mainly contribute to the selective oxidization of toluene into benzaldehyde. This work develops a new electrochemical strategy to achieve highly selective conversion of toluene into benzaldehyde with molecular oxygen under mild conditions.

Green Synthesis of Dimethyl Carbonate from CO2 and Methanol: New Strategies and Industrial Perspective

AbstractDimethyl carbonate (DMC) is a commonly used and environmentally sustainable chemical compound and intermediate in a variety of industrial applications. To date, several large‐scale industrial DMC synthesis routes have been developed, including methanol phosgenation, transesterification, and oxidative carbonylation of methanol. However, these manufacturing routes have several disadvantages, such as the use of hypertoxic phosgene as raw material, costly processing, and explosion risks. The most encouraging and ecofriendly path is the green production of DMC from CO2 and methanol. Various catalytic materials have been examined concerning their suitability for DMC synthesis. The issues of low yield and difficulty in tests have not been resolved fundamentally, which is caused by the inherent problems of the synthetic pathway and limitations imposed by thermodynamics. The search for more efficient production routes has driven the activation of CO2 via electro‐assisted synthesis as well as membrane reactors, which can isolate products in real‐time to maximize DMC yield. The green synthesis of dimethyl carbonate catalyzed by different catalysts including Zr/Ce/Cu‐based nanocomposites, organometallic compounds, heteropoly acid, ionic liquid, metal‐organic frameworks, etc, is discussed in detail. Further, the structure–activity relationships and insights into molecular activation and catalytic mechanisms, as well as the identification of active sites on catalysts are addressed.