To achieve the efficient conversion of lignin-derived phenolic compounds into high-value hydrocarbon fuels, a series of NiCo bimetallic catalysts with N-doped biochar and Al₂O₃ composite supports (NiCo/NC-Al₂O₃) were designed and synthesized in this study. Comprehensive characterizations (XRD, TEM, XPS, H₂-TPD) were conducted to reveal the superior catalytic activity in the HDO reaction of lignin-derived phenolic compounds. The optimized Ni₈Co₂/NC-Al₂O₃ catalyst exhibits good metal dispersion and excellent hydrogen dissociation adsorption capacity. Under mild reaction conditions (240°C, 1 MPa H₂), it achieves complete conversion of guaiacol and 99.9% selectivity of cyclohexane product, significantly outperforming the monometallic Ni₁₀/NC-Al₂O₃ and Co₁₀/NC-Al₂O₃ catalysts. Comparative studies indicate a synergistic effect between Ni and Co, where the introduction of Co effectively promotes the hydrogenation of aromatic rings and the cleavage of C−O bonds. This study elucidates the regulatory mechanism of the Ni-Co synergistic effect on catalytic performance, providing new insights for the development of efficient non-noble metals HDO catalysts.

Catalytic oxidation represents a pivotal technology for the valorization of light hydrocarbons, where oxidative dehydrogenation (ODH) and epoxidation reactions using molecular oxygen have garnered substantial interest owing to their high atom economy and environmental friendliness. This review systematically summarizes recent advances in the oxidative dehydrogenation of light alkanes (ethane, propane) and the aerobic epoxidation of light olefins (ethylene, propylene). In terms of rational catalyst design, this review elaborates on performance regulation strategies for metal oxide catalysts such as MoVNbTeO_x mixed oxides, NiO-based, and V-based systems, as well as carbon/boron-based non-metal catalysts in alkane oxidative dehydrogenation, along with silver-based and copper-based catalysts in alkene epoxidation. These strategies include regulating the oxidation state of active sites, strong metal-support interactions, particle size and crystal facet engineering, and promoter modification. At the mechanistic level, combining density functional theory calculations with in situ characterization techniques, this review delves into the C−H bond activation and alkene desorption pathways in oxidative dehydrogenation, along with the oxygen insertion routes and competing side reactions in epoxidation. Special attention is given to the dynamic evolution of electrophilic and nucleophilic oxygen species and their decisive role in reaction selectivity. Finally, the review outlines persistent challenges in the field, including suppressing over-oxidation and overcoming the trade-off between conversion and selectivity and proposes future research directions such as the precise design of active centers, development of inherently safer processes, and in-depth analysis of complex reaction networks, aiming to support the green transition of the chemical industry.

In this work, a Cu-based carbon catalyst (H-Cu/C) with an octahedral morphology was synthesized by pyrolyzing the metal-organic framework (MOF) precursor HKUST-1, where Cu(0) nanoparticles were uniformly dispersed in the carbon matrix, alongside the formation of island-like Cu₂O structures as the active sites. Multiple characterization techniques, including XPS, XRD, SEM and HRTEM, reveal the critical role of carbon matrix in stabilizing the metal nanoparticles. In combination with TEMPO and using molecular oxygen as a green oxidant, the H-Cu/C catalyst is highly efficient in the selective oxidation of aromatic alcohols to the corresponding aldehydes under alkali-free conditions. Using benzyl alcohol as a model substrate, an alcohol conversion of 99.2% and a benzaldehyde yield of 94.1% were achieved under mild reaction conditions (100 ℃, 0.5 MPa O₂, 1 h). The catalytic system displays excellent universality for various mono- and ortho/para-disubstituted aromatic alcohols, affording an alcohol conversion of over 99% and a yield of corresponding aromatic aldehydes of above 95%. In addition, the H-Cu/C catalyst can be regenerated via H₂ reduction and reused without significant loss of activity. This work provides a new strategy for designing green and efficient non-noble metal catalytic systems for the oxidation reactions.

Hydrodenitrogenation (HDN) process is an effective method for removing nitrogen-containing heteroatom compounds from inferior feedstocks. Its core lies in developing catalysts with both low cost and high performance. In this study, a FeZn-supported catalyst was modified by introducing six different metal promoters (La, Ti, Ce, Mn, Mg and Cr). It was found that Cr exhibited a pronounced promotional effect on HDN performance. The promoting effect of Cr on the FeZn catalyst’s activity originates from its electronic interaction with sulfided Fe species, rather than functioning as an independent active site. Specifically, Cr and Zn species act synergistically as electron donors, transferring electron density to the sulfided Fe species. This thereby modulates the electronic structure of Fe, rendering it in an electron-rich state. The increased electronic density weakens the Fe−S bonds in the active phase, thereby promoting their cleavage. Consequently, it promotes the formation of hydrogenation active sites, known as coordinated unsaturated sulfur vacancies (CUS). After introducing 3% Cr, under conditions of 340−380 °C, 4 MPa pressure, and a high weight hourly space velocity (WHSV) of 8.7 h⁻¹, the catalyst’s HDN conversion rate for the basic nitrogen compound quinoline increased by 14.5%−19.7% compared to the unmodified catalyst. The HDN conversion rate reached 81.9% at 380 °C. Furthermore, the introduction of Cr increased the number of medium-strength Lewis acid sites. These acid sites work synergistically with the increased CUS sites, enhancing the overall hydrogenation activity of the catalyst. Cr addition effectively governs the selectivity of the HDN pathway. Consequently, the reaction rate constant for the deep hydrogenation pathway over the FeZn3Cr@GA catalyst reaches 3.2 times higher that of the unmodified FeZn@GA catalyst. In summary, using Fe as the primary active metal component and regulating its electronic structure through promoters represents an effective approach for designing low-cost, high-performance HDN catalysts.

Polycarbonate (PC) is a widely utilized polymer in the chemical industry. Because toxic bisphenol A (BPA) leaches into the environment, the accumulation of waste PC poses a detrimental effect on both human health and the environment. To meet the demand for sustainable resource utilization and address environmental concerns, it is necessary to recover BPA from waste PC. In this work, methanol was used as the solvent to depolymerize PC via alcoholysis under the catalyst-free and mild condition. Experimental results demonstrated that PC could be depolymerized into BPA monomer at moderate temperature (120−160 °C). 100.0% degradation of PC plastic could be achieved with high BPA yield of 95.0% at 160 °C without the addition of catalysts or auxiliary solvents. In a scaled-up experiment of 10 g PC, a facile separation process of BPA was designed, and the recovery of BPA was more than 85.0%. Additionally, this method was also effective in depolymerizing actual plastic mixtures, such as ABS-PC and other polyesters such as polylactic acid, polyglycolic acid, and polyethylene terephthalate. Based on SEM and GPC results, a probable alcoholysis depolymerization mechanism for PC was proposed. These results indicated that methanol had a wide range of universality for the alcoholysis of various polyesters. This work presents a facile, green, and efficient approach for the alcoholysis recovery of polyesters plastics.

Oxidative coupling of methane (OCM) is an important way for the high-value utilization of methane (CH₄), but there are still some problems such as insufficient conversion and selectivity under traditional thermal catalysis. Herein, a new Mn₂O₃-TiO₂-Na₂WO₄/SiO₂+SiC microwave catalyst was developed for the oxidative coupling of methane under microwave irradiation. The results indicate that the calcined Mn₂O₃-TiO₂-Na₂WO₄/SiO₂+SiC catalyst is superior to the uncalcined counterpart in performance and the microwave catalytic reaction mode (MCRM) is significantly advantageous to the conventional reaction mode (CRM) for the OCM. For OCM at 700 ℃ in MCRM, the conversion of CH₄, the selectivity to C₂–C₃ hydrocarbons, and the yield of C₂–C₃ are 26.6%, 76.5% and 20.4%, respectively, much superior to the values of 12.3%, 61.9% and 7.5% in CRM under identical reaction conditions. That is, microwave irradiation can significantly enhance the yield of C₂–C₃ for OCM at a lower reaction temperature. The Mn₂O₃-TiO₂-Na₂WO₄/SiO₂+SiC catalyst shows favorable stability at 700 °C during the OCM reaction in MCRM for 20 h, with a methane conversion of above 25% and a selectivity of above 76% to C₂–C₃ hydrocarbons. Further study illustrates that the microwave irradiation can significantly reduce the apparent activation energy to 27.5 kJ/mol, compared with the value of 173 kJ/mol in the conventional mode, promote the free radical coupling and inhibit deep oxidation of OCM products. These results provide a new idea for the efficient conversion of CH₄ at a low temperature and for the sustainable development of green chemical industry.

Polyoxymethylene dimethyl ethers (DMM_x) are highly promising clean diesel additives. Compared to the traditional aldol condensation route, the one-step oxidative method for producing DMM_x directly from methanol is a green synthesis route offering significant advantages. However, due to the complexity of the reaction, a balance must be struck between oxidation depth and C–O chain growth efficiency. This imposes specific requirements on the design of catalysts with multifunctional active sites: the catalyst should possess appropriate oxidative activity, suitable acid strength distribution, and effective synergy between these two functions. To address these challenges, this study designed a sulfuric acid-modified molybdenum-doped NASICON catalyst, which demonstrated favorable catalytic performance in the one-step oxidative synthesis of DMM_x from methanol. Over the NSC-Mo-0.5-30% catalyst, methanol conversion rate of 81.3% and the DMM_x selectivity of 58.7% were achieved, along with the formation of heavier molecules, as evidenced by the DMM_2–6 selectivity of 11.3%. The NH₃-TPD, Py-IR and XPS results indicate that the introduction of molybdenum increases the number of weak Lewis acid sites, while sulfuric acid impregnation not only generates gradient-distributed Brønsted acid sites but also promotes the formation of Mo⁵⁺/Mo⁶⁺ redox pairs. The cooperation of the two types of active sites significantly enhances catalyst performance.

Biomass is considered as a sustainable green coal alternative, and its thermochemical conversion—particularly hydrogen-rich gasification technology—represents an effective pathway for achieving high-value utilization. Co-gasification of biomass with coal gangue enables synergistic utilization of carbon resources, offering significant potential for emission reduction and efficiency enhancement. To elucidate how typical biomass components govern the gasification process, three feedstocks with distinct, dominant characteristics were selected: pine stick (high cellulose content, representing highly reactive volatiles), soybean straw (high nitrogen, exemplifying feedstock prone to nitrogenous tar formation), and corn stover (high ash with abundant K⁺, reflecting catalytically active inorganics). Under fixed conditions (850 °C, steam flow rate of 2 mL/min, N₂ flow rate of 75 mL/min), their co-gasification with coal gangue was investigated. Results indicated that the compositional differences led to distinct synergistic patterns and product distributions. All systems achieved the highest hydrogen yield in the syngas at a 5∶5 raw material mass ratio. The high-cellulose pine stick system yielded the most H₂ (9.06 mmol/g) and H₂+CO yield (15.25 mmol/g), exhibiting a “three high, three low” advantage due to efficient volatile reforming. In contrast, the high-ash/K⁺ corn stover system showed the strongest synergy for CO (SI = 1.22, where the Synergy Index (SI) > 0 indicates a synergistic promoting effect), promoted by the catalytic Boudouard reaction. The high-nitrogen soybean straw system, while achieving an optimal H₂/CO ratio (2.00), suffered from suppressed syngas yield due to the inhibitory effect of nitrogenous tars. This study confirms that biomass composition-specifically cellulose, ash/K⁺, and nitrogen content-differentially regulates syngas production and synergy by steering dominant reaction pathways, providing a theoretical basis for the targeted conversion of waste resources.

Iron-based catalysts often undergo dynamic carburization and oxidation phase transitions in a CO₂/H₂ atmosphere. The identification of the active phase and the control of stability remain key challenges affecting their industrial application. This study employed a gas-solid carburization method to prepare high-purity single-phase χ-Fe₅C₂ (Hägg carbide) and θ-Fe₃C (cementite), with their structural purity systematically confirmed by XRD and Mössbauer spectroscopy (MES). Using techniques including fixed-bed reactor tests (H₂/CO₂=1, 0.1 MPa, 270–420 °C), pulse experiments (270 °C) and in situ XRD (10% CO₂/He, 340 °C), the catalytic performance and structural evolution pathways of these carbides in the reverse water-gas shift (RWGS) reaction were thoroughly investigated. The results indicate that χ-Fe₅C₂ exhibits higher RWGS activity but is more susceptible to oxidation during the reaction. In contrast, θ-Fe₃C demonstrates stronger anti-oxidation stability but lower RWGS activity. Under RWGS conditions with H₂, θ-Fe₃C can partially transform into χ-Fe₅C₂. However, in 10% CO₂ atmosphere, both carbides are directly oxidized to Fe₃O₄, with no observed phase transformation between the iron carbides. These findings reveal the differences in the evolution mechanisms of χ-Fe₅C₂ and θ-Fe₃C under different atmospheres, providing experimental basis for the regulation of phase structure and optimization of operational stability in iron-based Fischer-Tropsch and RWGS catalysts.

As a clean fuel and important chemical raw material, the efficient production of liquefied petroleum gas (LPG) has attracted widespread attention. This manuscript summarizes the current research progress on the hydrogenation of CO and CO₂ (CO_x) to produce LPG. Specifical emphasis is focused on the design and optimization of bifunctional catalysts, evaluating the adsorption and activation of CO_x on different metal oxide surfaces, as well as the influence of pore structure and acidity of zeolites on LPG selectivity. The synergistic effects between metal oxide and zeolite components in promoting LPG production and enhancing catalyst stability are elucidated, aiming to provide theoretical guidance for the development of highly efficient catalytic systems.