The extensive emission of greenhouse gases, primarily CO₂ and CH₄, has contributed to intensified global warming. Dry reforming of methane (DRM, CH₄ + CO₂ → 2CO + 2H₂) offers a pathway for the synergistic utilization of these two major greenhouse gases, presenting important implications for both environmental protection and energy sustainability. However, the catalysts still face the challenges such as carbon deposition and sintering of active metals, which adversely affect the catalytic performance and long-term stability. Oxygen vacancies, which are common lattice defects in metal oxides, have been demonstrated to improve the DRM performance by modulating the surface and interfacial properties of the catalysts. This review systematically summarizes research progresses in DRM over the past decade, outlines the major challenges and emphasizes the critical roles of oxygen vacancies in suppressing carbon deposition and inhibiting metal sintering. Furthermore, the mechanisms through which oxygen vacancies influence DRM reactions are discussed, combined with their formation pathways and regulation strategies. These insights provide essential theoretical foundations for the design and synthesis of highly efficient and stable DRM catalysts.

Para-xylene (PX), as a pivotal chemical feedstock, plays an indispensable role in ensuring nation energy strategic security and propelling the low-carbon and green development of the chemical industry. The review systematically summarizes the recent advancements in catalysts for the direct conversion of syngas into p-xylene-enriched aromatics, focusing on three distinct catalytic systems: the Fischer-Tropsch synthesis catalyst/zeolite coupling system, the methanol synthesis catalyst/zeolite synergistic system, and the dual engine driven/zeolite catalytic system. Through a comprehensive and in-depth analysis of critical parameters, including the electronic structure features of active components, the synergistic action mechanism of promoters, and the pore topology of zeolite within each catalytic system, the governing principles of catalytic activity, selectivity, and stability are thoroughly revealed. Simultaneously, based on the reaction intermediate evolution pathways, the reaction mechanisms involving olefin, methanol, and olefin-methanol dual intermediate routes are systematically explored. The current scientific bottlenecks confronted by the catalyst systems, such as the intricate challenge of achieving coordinated optimization of activity and stability, and the lack of clarity in the regulatory mechanism of PX directional selectivity, are meticulously expounded. Building upon these identified issues, prospective research directions are comprehensively summarized.

Co-pyrolysis of oil-rich coal and biomass is an effective approach to maximize the oil and gas production from oil-rich coal. To address the challenge of unclear mechanisms for the enhancement of synergistic effects during the co-pyrolysis of oil-rich coal and biomass, a Huangling coal (H) and an enzymatic hydrolysis lignin (E) were used as the research samples and the structural evolution of raw materials and those by hydrothermal pretreatment (HTP) was systematically investigated using a suite of techniques such as proximate analysis, ultimate analysis, scanning electron microscopy (SEM), inductively coupled plasma optical emission spectrometry (ICP-OES) and nuclear magnetic resonance (¹³C-NMR). Combined with fixed-bed pyrolysis experiments, the mechanism by which hydrothermal pretreatment strengthens the co-pyrolysis synergistic effect of the Huangling coal and enzymatic hydrolysis lignin blend was explored. The results indicate that after hydrothermal pretreatment, the oxygen content of the raw materials decreases, the pore structure becomes more developed, and the concentrations of inorganic metal ions (e.g., calcium, potassium, and iron) in the aqueous phase increase. The structure of Huangling coal and enzymatically hydrolyzed lignin undergoes significant modification, with the contents of aliphatic carbon, aromatic carbon and carbonyl/carboxyl carbon in enzymatically hydrolyzed lignin approaching those in Huangling coal, and with the bridge carbon ratio increasing, resulting in improved thermal stability for the enzymatically hydrolyzed lignin and a pyrolysis temperature approaching that of Huangling coal. By the hydrothermal pretreatment, the co-pyrolysis of Huangling coal and enzymatic hydrolysis lignin generally exhibit an increase in tar yields. When the H/E ratio is 8∶2 and hydrothermal pretreatment is conducted for 24 h, the co-pyrolysis tar yield increases by 80.52%, with significant increases in the contents of aliphatic compounds and monocyclic aromatic hydrocarbons in the tar. Meanwhile, the yields of H₂, CO and CH₄ in the gas increase by 5.47%, 10.98% and 9.27%, respectively, the generation of CO₂ and pyrolysis water is inhibited, and the pore structure of semi-coke is enriched. This is primarily attributed to the multiple mechanisms of “component interaction-structural modification-catalytic cracking” during hydrothermal pretreatment, which enhance the co-pyrolysis synergistic effect of the H/E blend. The findings provide theoretical support for developing the technologies to enhance the co-pyrolysis synergistic effect between oil-rich coal and biomass, and expand new avenues for the low-carbon, high-quality utilization of oil-rich coal.

The improper disposal of plastic waste represents both the loss of valuable resources and significant environmental threat. To address this issue, this study investigates the thermal liquefaction of high-density polyethylene (HDPE) using low-pressure superheated methanol. It systematically evaluates the effects of the reaction temperature and the ratio of reactant to methanol on the liquefaction efficiency and product characteristics. Results indicate that the complete conversion of HDPE could be achieved in low-pressure superheated state methanol (<0.5 MPa) at a minimum external heating temperature of 260 °C. Under this condition, the oil yield reached 77.1% with alkanes comprising 62.3% of the product alongside minor oxygenated compounds. As temperature increased, the average carbon number of hydrocarbons gradually decreased. Below 260 °C, the HDPE conversion decreased significantly, and the products were primarily waxy. At 290 °C, the proportion of gasoline-like fractions (C6–C12) increased markedly from 16.6% to 80.9%. Furthermore, reactant ratio plays a critical regulatory role; extremes in ratio—either too high or too low—diminish heat transfer efficiency and reduce conversion. Mechanistically, the liquefaction primarily involved the cleavage of secondary C−C bonds, where the resulting oligomers further cracked into free radicals to form diverse hydrocarbons through secondary reactions. This work demonstrates that low-pressure superheated methanol liquefaction is a mild, efficient, and pretreatment-free method to upcycle polyethylene into valuable fuels. Optimizing these process parameters can pave the way for industrial application, aiding in both plastic pollution management and sustainable resource recovery.

Volatile organic compounds (VOCs) originating from diverse sources, exert a profound detrimental impact on the atmospheric environment and pose grave threats to human health. Manganese (Mn)-based catalysts, celebrated for their exceptional structural diversity and abundant redox versatility, are extensively employed in the catalytic combustion of VOCs. This review summarizes the catalytic performance of diverse Mn-based catalysts. It emphasizes strategies for preparing high-performance Mn-based catalysts and provides a systematic analysis of how the construction of active sites influences their catalytic combustion performance for VOCs. Furthermore, the catalytic oxidation mechanisms of VOCs are expounded in detail. This work offers valuable insights and practical guidance for the remediation of VOCs pollution.

The coupling of CO₂ with olefins to produce cyclic carbonates has emerged as an important research topic in sustainable chemistry, owing to its high atom economy and the wide applicability of the resulting products. However, this reaction faces a significant challenge due to the mismatch between the rates of the epoxidation and cycloaddition steps. In this work, a series of TS-1 zeolite catalysts encapsulating different amounts of molybdenum acetylacetonate were prepared through hydrothermal synthesis followed by post-treatment, with the aim of elucidating the rate balance between the epoxidation and cycloaddition steps and the underlying regulation mechanism. Characterization results show that the Mo species were present as highly dispersed molybdenum acetylacetonate complexes that were stably confined within the TS-1 framework. These complexes interact electronically with the tetra-coordinated Ti sites to form synergistic active centers, while imposing negligible effects on the zeolite structure and porosity. In the CO₂-styrene coupling reaction, tuning the Mo loading enabled effective control over the epoxidation rate, thereby achieving an appropriate balance with the subsequent cycloaddition step. The optimized catalyst delivered excellent performance under mild conditions, with a styrene conversion of 83.4% and a selectivity of 75.3%, and also exhibited outstanding recyclability. Overall, this encapsulated catalyst successfully addresses the dual challenges of rate matching and active-site stability in CO₂–olefin coupling, providing valuable insights for the rational design of efficient, durable bifunctional catalysts.

Ni/Al₂O₃ is regarded as one of the most promising catalysts for industrial application in CO₂ methanation, but is still plagued by issues of inadequate low-temperature activity and thermal sintering. In response to these challenges, an Ni/CaO-ZrO₂-Al₂O₃ catalyst with high low-temperature activity and robust high-temperature sintering resistance was prepared by introducing Ca and Zr promoters. Under the reaction conditions of 250 °C and a space velocity of 30000 mL/(g·h), the CO₂ conversion and methane space-time yield reached 96% and 257.5 mmol/(g·h), respectively. In addition, the Ca-Zr dual-promoted Ni/CaO-ZrO₂-Al₂O₃ catalyst exhibited a smaller increase in the Ni particle size and less activity loss than the Ca-promoted catalyst in a 200 h aging test at 600 °C. The Ca and Zr promoters can not only improve the Ni dispersion but also enhance the surface basicity, resulting in excellent low-temperature activity. Moreover, the Zr promoter suppresses the transformation of Ca species into CaCO₃ through solid-phase reaction under operating conditions, thereby inhibiting Ni sintering and ensuring high-temperature stability. This work provides a new promoter design strategy for the development of high-performance Ni-based catalysts for CO₂ methanation.

Carbon deposition caused by mass transfer limitations is a key challenge for traditional microporous ZSM-5 zeolites in the process of coal tar catalytic cracking. To address this problem, benzene was selected and used as a model compound for coal tar in the study. The parent ZSM-5 (NL-ZSM-5) was modified with tetraethylammonium hydroxide (TEAOH) to prepare hierarchical ZSM-5 zeolites with different mesopore sizes. A suite of characterization techniques (XRD, FT-IR, BET, TEM) were combined with fixed-bed experiments and molecular simulations to systematically investigate the effects of pore structure, acidic properties, and reaction temperature on the coking mechanism. The characterization results confirmed that mesopores were successfully introduced via the selective desilication with TEAOH, while the original MFI topological structure was retained. When TEAOH concentration is 0.4 mol/L (ZSM-5-C), the total pore volume increases from 0.24 to 0.43 cm³/g, and the amount of Brønsted acid (B acid) increased from 0.28 to 0.67 mmol/g. Moreover, the acid site accessibility was significantly improved. Analysis of catalytic experiments and carbon deposition indicate that carbon deposition is effectively inhibited in the hierarchical pore structure through a synergistic effect of “diffusion enhancement and adsorption-site regulation”. The coke amount of ZSM-5-C is 4.0%, which is only one-third of that of the pure microporous NL-ZSM-5 (11.9%). The results of molecular dynamics simulations confirm that the diffusion coefficient of benzene in the 3.0 nm mesopore model is an order of magnitude higher than that in the 2.0 nm model. Furthermore, the adsorption capacity decreases with the increasing in mesopore size, resulting in a shorter residence time of molecules within the pore channels. In addition, although increasing the temperature can enhance the molecular diffusion rate, it also exponentially intensifies surface condensation reactions (Arrhenius effect), which becomes the dominant driver of coke formation. The hierarchical pore structure, however, can effectively mitigate this negative effect. This research provide a theoretical basis for the design of high-efficiency and coke-resistant catalysts for coal tar conversion.

Aldehydes and ketones, valuable oxygen-containing organic intermediates, play a fundamental role in the synthesis of fine chemicals, fuels and materials. Renewable carbon resources, represented by lignocellulosic biomass, enable the green production of platform carbonyl compounds such as furfural, 5-hydroxymethylfurfural, and low-molecular-weight aliphatic ketones via pyrolysis. This approach is of great significance for mitigating dependence on fossil resources and reducing carbon emissions. This review provides a systematic overview of recent progress in the catalytic pyrolysis of biomass for aldehyde and ketone production. First, the structural features, types, and biomass-derived origins of typical carbonyl platform molecules are summarized. Second, the decomposition pathways and intermediate evolution behaviors of cellulose-rich, hemicellulose-rich, and lignin-rich biomasses under non-catalytic pyrolysis conditions are compared, clarifying the influence of multicomponent synergistic effects on aldehyde and ketone formation. On this basis, particular emphasis is placed on the mechanistic roles and dominant reaction pathways of metal salts, metal oxides, and carbon-based catalytic systems in regulating key steps such as dehydration, decarbonylation, C−O/C−C bond cleavage, and skeletal rearrangement. Finally, the main challenges in biomass catalytic pyrolysis toward aldehydes and ketones are analyzed, including unclear catalyst structure-activity relationships, inadequate active site stability, and limited product selectivity. Future perspectives are proposed regarding the rational design of multilevel structured catalysts for efficient and controllable conversion, the integration of in situ characterization with multiscale simulation to elucidate reaction mechanisms, and the development of green scale-up and process integration strategies. This work aims to provide a systematic theoretical reference and research guidance for the high-value utilization of biomass and the conversion of renewable carbon resources.

Inherent minerals play a significant role in the thermal conversion of coal. However, the influence mechanism of the interactions among minerals on the generation of tar during coal pyrolysis remains unclear. To investigate the mechanism of the effect of acidic mineral components on the behavior of Ca²⁺ during coal pyrolysis, several samples were prepared by HCl and HF washing and Ca²⁺ ion exchanging. The pyrolysis behaviors of the experimental coal samples were examined in a fixed-bed reactor. During the acid washing process, the ash content was effectively reduced, while the contents of organic elements such as carbon and hydrogen were also decreased. The loading of ion-exchangeable calcium enhanced the thermal weight loss rate of the coal sample in the 500–550 °C range, and the corresponding peak temperature shifted from 530 to 514 °C for the coal without Ca. When coal was pyrolyzed at a final temperature of 600 °C with a slow heating rate, kaolinite in acidic mineral components undergoes dehydroxylation to form metakaolin, and the content of small aromatic rings (<6 rings) in the char pyrolyzed by Ca-loaded coal sample was lower than that of the coal sample after acid washing. Due to the coexistence of acidic mineral components with ion-exchangeable Ca, the content of aliphatic hydrocarbons in the pyrolysis tar of YL-HCl-Ca reached 21.98%, significantly higher than 13.60% in the corresponding pyrolysis tar of YL-De-Ca. From the apparent results, it can be found that the acidic mineral components inhibit the adverse effect of ion exchangeable Ca²⁺ on the lightening of coal tar.

Coal gasification fine slag (CGFS) is a solid waste generated from entrained-flow coal gasification, characterized by fine particles and rich in silicon and aluminum elements. Using CGFS as a raw material for the preparation of ZSM-5 molecular sieves enables the high-value utilization of coal-based solid waste, offering significant economic and environmental benefits. This study proposes a simple and economical hydrothermal synthesis process for ZSM-5 using CGFS as the raw material. In this process, impurities in CGFS were first removed by acid washing, which facilitated the subsequent alkaline extraction of silicon and aluminum species. The extracted Si-Al precursors were then converted into ZSM-5 via hydrothermal crystallization at 170 °C for 48 h, yielding a product with a high specific surface area of 358 m²/g. Adsorption experiments demonstrated that the synthesized ZSM-5 exhibited excellent adsorption performance for Pb²⁺ in aqueous solutions. At 25 °C, the removal efficiency for a 50 mg/L Pb²⁺ solution reached 83.7%, with an adsorption capacity of 104.625 mg/g under optimized conditions. The adsorption process is mainly governed by chemisorption mechanisms, including surface complexation, precipitation, and ion exchange. The synthesized ZSM-5 shows promising potential for application in the treatment of lead-containing wastewater.

To investigate influence of mixing modes on integrated process of co-pyrolysis of coal and biomass with CO₂ reforming of methane (CP-CRM), Naomaohu coal (NMH) and elm (ELM) were chosen and three mixing modes (NMH/ELM, ELM/NMH and Blends) were examined over Ni-based reforming catalysts prepared by ball milling, and compared with co-pyrolysis under N₂ atmosphere (CP-N₂). The results show that the products distribution was significantly affected by the mixing mode. Tar yield during CP-CRM under Blends model was higher than those of NMH/ELM and ELM/NMH, increasing by 35.29% compared with CP-N₂. Meanwhile, light oil content in the tar was higher than those of NMH/ELM and ELM/NMH, but the pitch content was opposite. Phenols content in tar from Blends model was 19.52% higher than that of CP-N₂, along with more free radicals in tar than that of CP-N₂, which was mainly ascribed to the enhanced heat and mass transfer between raw material particles by mechanical mixing, making the co-pyrolysis process more complete. At the same time, the mechanical mixing was conducive to more efficient action of hydrogen-rich free radicals (such as ·H, ·CH_x) on pyrolysis products, suppressing the secondary cracking and polymerization. The results provide a good guidance for regulating tar yield and compositions of the co-pyrolysis process.

The catalytic conversion of C1 molecules (e.g., CO, CO₂) represents a pivotal technology in the energy and chemical sectors, essential for achieving sustainable C1 chemistry and low-carbon transformation. A profound understanding of the underlying microscopic reaction mechanisms necessitates systematic support from both theoretical and experimental data support. This study constructs a “Computational Dataset for C1 Molecular Catalytic Conversion Based on Iron-Based Catalysts,” focusing on Fe₅C₂-based catalysts and systematically integrating multidimensional information on C1 molecular adsorption, dissociation, and formation reactions across different crystal surfaces (001, 111, 510). The dataset includes: the number of polycrystalline surface structures (Fe₅C₂(001) with 96 configurations, Fe₅C₂(111) with 93, and Fe₅C₂(510) with 472); species involved in the full reaction pathways under complex co-adsorption environments (adsorbed states such as COH and H₂, dissociated states like CO under 2H conditions, and formation states such as CH/CH₃ under 2H and H₂O conditions); and a standardized hierarchical storage system categorizing reaction types, crystal surfaces, and structural parameters. This dataset not only serves as a benchmark for validating quantum chemical calculation methods but also provides critical data support for catalyst design and reaction pathway optimization in C1 molecular catalytic conversion by uncovering the coupling effects of crystal surfaces and reaction mechanisms.

The carbonylation of glycerol with carbon dioxide (CO₂) to produce glycerol carbonate is an effective route for the resource utilization of CO₂, which can not only alleviate the carbon emission but also enable the synthesis of value-added chemicals. As this reaction process suffers from low glycerol conversion due to the thermodynamic limitation, introducing a coupling agent besides an appropriate catalyst is necessary to achieve the efficient synthesis of glycerol carbonate. This article systematically reviews the recent research progress in the homogeneous catalysts (inorganic bases and organic bases) and heterogeneous catalysts (Zn, Cu, Ce, La, Mg, noble metal, modified zeolite, non-metallic materials, etc.) for the direct carbonylation of glycerol with CO₂. The strategies such as metal oxide modification, support optimization, precursor selection, and construction of acidic-basic sites to enhance the catalytic performance are analyzed, while the effects of coupling agents (acetonitrile, adiponitrile, 2-cyanopyridine, MgCO₃, CaC₂, NaHCO₃, etc.) are summarized. Among them, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), Zn(QTf)₂, and metal composite oxides such as ZnO-CeO₂ have demonstrated promising catalytic performance in the carbonylation of glycerol with CO₂. To enhance the efficiency for the carbonylation of glycerol with CO₂, following measures should be taken in the future: developing organometallic complexes or composite metal oxides with highly dispersed active sites and specially tailored morphologies to modulate the surface area, pore size, and surface acidity/basicity of the catalysts; optimizing coupling agents or designing novel membrane reactors to improve the glycerol conversion; introducing polar solvents to improve the adsorption and activation capabilities of reactants and thereby to boost the catalytic activity. All these would provide valuable references for the catalyst design and reaction system optimization in the carbonylation of glycerol with CO₂.