In this study, sixteen types of lignin monomer model compounds with aldehyde and carboxyl substituents at the C_α or C_β positions were selected, representing phenyl, p-hydroxyphenyl, guaiacyl, and syringyl structural units. The catalytic effects of alkaline earth metal ions (Ca²⁺ and Mg²⁺) on the formation of CO and CO₂ during lignin pyrolysis were investigated by using density functional theory (DFT) calculations. The results revealed that Ca²⁺ and Mg²⁺ readily coordinate with oxygen-containing functional groups in lignin model compounds, forming stable complexes with lower energy states. When aldehyde, carboxyl, phenolic hydroxyl, and methoxy groups coexist, the optimal binding sites for Ca²⁺ and Mg²⁺ are O(phenolic hydroxyl)–Ca²⁺/Mg²⁺–O(methoxyl) configurations. During the pyrolysis process of lignin monomers, Ca²⁺ and Mg²⁺ selectively promote the decarbonylation of benzaldehyde-type and phenylethanal-type lignin monomer model compounds (excluding phenylethanal and 4-hydroxyphenylethanal), thereby enhancing the generation of CO. Conversely, except for the Ca²⁺-catalyzed decarboxylation of 4-hydroxy-3-methoxyphenylethanoic acid, Ca²⁺ and Mg²⁺ can suppress the decarboxylation of benzoic acid-type and phenylacetic acid-type lignin monomer model compounds, resulting in the reduction of CO₂ formation.

A series of Ni-Co bimetallic oxides were synthesized via a microwave-assisted hydrothermal method. The phase structure, morphological features, valence states, and defects of the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR). The results reveal the regulatory mechanism of Ni-Co bimetallic synergy on the formation of oxygen vacancies (O_v). When the molar ratio of Ni to Co was 1∶3, the obtained NiCo₃O_x exhibited the best OER performance, delivering an overpotential of only 393 mV at a current density of 50 mA/cm², along with a low Tafel slope (172.3 mV/dec) and catalytic stability exceeding 24 h. This superior activity is attributed to the synergistic redox interplay between Co²⁺/Co³⁺ and Ni²⁺/Ni³⁺, as further verified by in situ Raman spectroscopy, which confirmed that ^*OOH intermediate adsorption promoted reaction kinetics and that O_v mediated rapid electron transfer. Density functional theory (DFT) calculations further demonstrated that electronic coupling at the bimetallic interface enhanced the material’s conductivity. This study provides a new strategy for designing efficient OER catalysts based on oxygen-vacancy regulation.

Oxygen carriers play a fundamental role in chemical looping combustion (CLC). Iron-based carriers have been extensively investigated owing to their abundance and environmentally friendly. However, the reactivity and separability of iron-based carriers require further enhancement. This study investigates the effect of the concentration of Mn doping on reactivity, elastic properties and magnetic properties based on density functional theory (DFT) calculations. Theoretical results demonstrate that Mn doping effectively enhances reactivity by reducing the oxygen vacancy formation energy ($ {{E}}_{\text{vac}} $) from 2.33 to 0.87 eV. However, Mn doping introduces lattice distortions that deteriorate elastic properties, thereby reducing wear resistance, as evidenced by a 54.54% decrease in the hardness-to-Young's modulus ratio ($ {{H}}_{\text{V}}\text{/}{{E}}_{\text{V}} $) for α-Fe₂O₃ and an 83.33% reduction for Fe₃O₄. Furthermore, Mn doping also modifies magnetic properties. The maximum of saturation magnetization ($ {{M}}_{\text{s}} $) of Fe₃O₄ reaches 121.02 emu/g at 33.33% Mn doping concentration. Finally, systematic evaluation identifies 33.33% as the optimal Mn doping concentration, achieving a balance in enhanced reactivity, superior magnetic performance, and retained elastic stability.

To deepen understanding of the evolution of coal char microstructural properties of coal char during the co-pyrolysis of coking coal with additives, this study incorporated two typical additives, coal tar pitch (CTP) and waste plastic (HDPE), into a blended coal sample and carried out pyrolysis experiments. The pyrolysis process and the microstructure of char were systematically characterized using various analytical techniques, including thermogravimetric analysis (TGA), X-ray diffraction (XRD) and Raman spectroscopy. Data correlation analysis was performed to reveal the mechanism of carbon structural ordering evolution within the critical temperature range (350−600 °C) from colloidal layer formation to semi-coke conversion in coking coal, and to elucidate the regulatory effects of different additives on coal pyrolysis pathways. The results indicate that HDPE releases free radicals during high-temperature pyrolysis, accelerating the pyrolysis reaction and increase the yield of volatile components. Conversely, CTP facilitates pyrolysis at low temperatures through its light components, thereby delaying high-temperature reactions due to the colloidal layer’s effect. XRD results indicate that during the process of pyrolysis, there is a progressive decrease in the interlayer spacing of aromatic layers (d₀₀₂), while the aromatic ring stacking height (L_c) and lateral size (L_a) undergo significant of carbon skeleton ordering. Further comparative reveals that CTP partially suppresses structural ordering at low temperatures, whereas HDPE promotes the condensation and alignment of aromatic clusters via a free radical mechanism. Raman spectroscopy reveals a two-stage reorganization mechanism in the microstructure of the coal char: the decrease in the I_D/I_G ratio between 350 and 550 °C is primarily attributed to the cleavage of aliphatic side chains and cross-linking bonds, leading to a reduction in defective structures; whereas the increase in I_D/I_G between 550 and 600 °C is closely associated with enhanced condensation reactions of aromatic structures. Correlation analysis further demonstrates progressive graphitization during pyrolysis, with a significant positive correlation (R² > 0.85) observed between d₀₀₂ and the full width at half maximum of the G-band (FWHM-G).

Biomass-based hydrocarbon fuels, as one of the alternatives to traditional fossil fuels, have attracted considerable attention in the energy field due to their renewability and environmental benefits. This article provides a systematic review of recent research progress in the chemical synthesis of biomass-based hydrocarbon fuels. It outlines the conversion pathways using feedstocks such as lipids, terpenoids, cellulose/hemicellulose, and lignin. Depending on the feedstock, various products with distinct structural characteristics can be prepared through reactions such as cyclization, condensation, and catalytic hydrogenation. Throughout the synthesis process, three key factors play a critical role: efficient catalyst development, production process optimization, and computational-chemistry-based molecular design. Finally, the article discusses future perspectives for biomass-based hydrocarbon fuel synthesis research.

Aiming at the problems of insufficient activity and selectivity of Cu-based catalysts in CO₂ hydrogenation to methanol, Al₂O₃, ZrO₂ and CeO₂ modified Cu-ZnO catalysts by the co-precipitation method were prepared, and the influence mechanism of additives on the structure-performance relationship of the catalysts was systematically explored. Through a variety of characterization methods such as XRD, N₂ physical adsorption-desorption, TEM, H₂-TPR, CO₂-TPD and XPS, combined with catalytic performance evaluation experiments, the correlation between the microstructure of catalysts and the reaction performance of CO₂ hydrogenation to methanol was analyzed in depth. The results show that metal additives significantly improve the performance of catalysts. After the introduction of additives, the specific surface area and pore volume of the catalysts increase, the grain size of Cu decreases, and its dispersion improves. The Ce-modified CZC catalyst exhibited the best performance, with the grain size of CuO as small as 11.41 nm, and the surface oxygen vacancy concentration (O_Ⅱ/O_Ⅰ = 3.15) was significantly higher than that of other samples. The reaction performance test shows that under the conditions of 2.8 MPa, 8000 h⁻¹ and 280 °C, the CO₂ conversion of the CZC catalyst reached 18.83%, the methanol selectivity was 68.40%, and the methanol yield was 12.88%, all of which are superior to other catalysts. Its excellent performance can be attributed to the fact that CeO₂ enhances the metal-support interaction, increases the surface basicity, promotes the adsorption and activation of CO₂, and simultaneously inhibits the reverse water-gas shift side reaction. This study clarifies the structure-activity regulation mechanism of additive modification on Cu-ZnO catalysts, providing a theoretical basis and technical reference for the development of efficient catalysts for CO₂ hydrogenation to methanol.

KIT-5/Beta composite supports were synthesized using an in situ self-assembly hydrothermal method, and NiW/KIT-5/Beta catalysts were prepared by impregnation. A series of characterization techniques were utilized to evaluate the influence of varying hydrothermal synthesis temperatures on the physicochemical properties of both the KIT-5/Beta supports and the resulting catalysts. The catalytic performances of catalysts were evaluated under reaction conditions of 320  °C, 4 MPa H₂ pressure, and a weight hourly space velocity (WHSV) of 4.8 h⁻¹ for hydrodenitrogenation (HDN) of quinoline. The results indicated that the specific surface area and pore structure of the materials could be effectively regulated by adjusting the hydrothermal synthesis temperature, which in turn influenced the number of active sites on the catalyst. The NiW/KB-125 catalyst, synthesized at 125  °C, presented the highest quinoline HDN efficiency (96.8%), which can be attributed to its favorable pore channel structure, greater Brønsted acid number, higher degree of metal sulfidation (80.12%) and appropriate metal-support interaction (MSI).

Needle coke, a high-performance artificial carbon material, requires precise composition control of its raw materials as this critically determines the structural characteristics and performance of the final product. In this study, needle coke samples were prepared from coal direct liquefaction pitch (CDLP) and waste engine oil (WEO) through component optimization and a co-carbonization process. The microstructure and properties were investigated using the following characterization techniques: Fourier Transform Infrared Spectroscopy (FT-IR), Polarized Light Microscopy (PLM), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Raman Spectroscopy, Thermogravimetric Analysis (TGA), Micro-Strength (MS) and Powder Resistivity (PR). The co-carbonization mechanism of CDLP and WEO was systematically investigated. The results indicated that the incorporation of WEO significantly reduced the viscosity of the co-carbonization system, and its abundant aliphatic structures provided alkyl radicals and active sites. The synergistic interaction of aromatic components between the CDLP and WEO effectively promoted the growth and order accumulation of aromatic carbon layers. When 50% WEO was introduced, the prepared needle coke exhibited an excellent microstructure and properties. The fibrous and leaflet structure content reached 76.2%, the ideal graphite lattice content reached 89.7%. These results demonstrated remarkable oxidation resistance and electrical conductivity, with a powder resistivity of 605.1 mΩ·mm. This work establishes a process with cost advantages for the production of needle coke.

In this study, a straightforward one-step hydrothermal method was successfully utilized to synthesize the solid solution Na_0.9Mg_0.45Ti_3.55O₈-Na₂Ni₂Ti₆O₁₆ (NNMTO-x), where x denotes the molar percentage of Na₂Ni₂Ti₆O₁₆ (NNTO) within Na_0.9Mg_0.45Ti_3.55O₈ (NMTO), with x values of 10, 20, 30, 40, and 50. Both XPS (X-ray Photoelectron Spectroscopy) and EDX (Energy Dispersive X-ray Spectroscopy) analyses unequivocally validated the formation of the NNMTO-x solid solutions. It was observed that when x is below 40, the NNMTO-x solid solution retains the structural characteristics of the original NMTO. However, beyond this threshold, significant alterations in crystal morphology were noted, accompanied by a noticeable decline in photocatalytic activity. Notably, the absorption edge of NNMTO-x (x<40) exhibited a shift towards the visible-light spectrum, thereby substantially broadening the absorption range. The findings highlight that NNMTO-30 possesses the most pronounced photocatalytic activity for the reduction of CO₂. Specifically, after a 6 h irradiation period, the production rates of CO and CH₄ were recorded at 42.38 and 1.47 μmol/g, respectively. This investigation provides pivotal insights that are instrumental in the advancement of highly efficient and stable photocatalysts tailored for CO₂ reduction processes.

Considering that coal quality is a key factor affecting the performance of coal water slurry (CWS), in this research, the composition and structure of five coal samples from the Xinjiang-Zhundong coal B2, B3, B5, Heishan coal (HS), Hongshaquan coal (HSQ) and Naomaohu coke (XTJ)-were analyzed, aiming to investigate the influence mechanisms of single coals and coal/coke blending on slurryability. The results showed that the HS, characterized by the aromatic carbon skeleton dominated by 2−3 rings, exhibited low oxygen content and few hydrophilic phenolic hydroxyl, carbonyl, and carboxyl groups, which contributed to its superior slurry performance compared to other coal samples. Even at a remarkably high slurry concentration of 70.98%, the apparent viscosity remained as low as 858 mPa·s. In contrast, B3 and B5 exhibited poor slurry performance due to their abundant oxygen-containing functional groups and strong hydrophilicity, which reduced free water content in the slurry. Additionally, the high content of adsorbed water indicated a thicker hydration film on coal particle surfaces, hindering dispersant adsorption. The addition of 20% HS/XTJ to B5 disrupted the three-dimensional network structure formed by clustered particles and covered the oxygen-containing functional groups. This process not only released previously encapsulated water but also reduced hydration layer thickness. Consequently, free water content increased within the slurry, enhancing dispersant performance. These effects collectively increased coal slurry concentration by approximately 2.40% (reaching 59.00%), reduced apparent viscosity by ~40%, and improved fluidity to an A⁺ rating.