Hydropyrolysis has been identified as a promising approach for generating fuels and high-value chemicals. However, the reaction mechanism under hydrogen conditions remains to be explored. In this study, ReaxFF molecular dynamics simulations were employed to investigate the detailed reaction pathways of a structurally representative Adler softwood lignin model. By systematically varying hydrogen pressure and temperature, the influence of hydrogen availability on product distribution, bond cleavage behavior, and the evolution of reactive intermediates was elucidated. The simulations, supported by our previous experimental observations, demonstrate that elevated hydrogen pressures enhance deoxygenation efficiency and selectively promote the formation of low-oxygen hydrocarbons. Key radical species such as H center dot, CHO center dot, and CH3 center dot were identified as crucial participants in the dominant reaction pathways, with their generation significantly facilitated under high hydrogen concentrations. Additionally, higher temperatures further intensified bond dissociation and product evolution. In summary, this study offered valuable insights into lignin pyrolysis with the introduction of hydrogen.

Flame morphology's characteristics and self-acceleration phenomenon are the basis for flame instability experimental research, but their relationship has not been quantitatively investigated. This work developed a 3D reconstruction technique based on binocular shadow imaging and computer vision to reconstruct bio-jet fuel (1,3-dimethylcyclohexane) unstable flame cracks and cellularity. The experiment was conducted in a constant volume combustion chamber with an initial temperature of 400 K and equivalence ratios of 1.3-1.5 and 1.2-1.4 corresponding to initial pressures of 2 bar and 4 bar, respectively. The 3D measurement has significant advantages over the 2D measurement. The increase in initial cracks does not greatly influence the flame surface area and speed. The flame speed and morphology parameters have unstable transition and saturation stage characteristics. The transition and saturation critical Peclet numbers obtained from them are consistent within the error range of this study, indicating that the unstable development stages of flame speed coincide with those of flame morphology. The fractal dimension of the unstable flames was experimentally determined through the flame surface area for the first time and compared with that obtained by flame acceleration. This study contributes to a deeper understanding of the two characteristics of flame hydrodynamic instability, namely the interrelationship between flame speed and morphology, and provides new methods for the three-dimensional reconstruction of flames.

The valorization of polyethylene terephthalate (PET) waste into value-added chemicals coupled with hydrogen production presents a promising sustainable solution, yet is hindered by inefficient electrocatalysts. Herein, we engineer a bifunctional cobalt oxide nanoflower catalyst anchored on Ni foam (Co₃O₄-F@NF) with tailored spinel structure and morphology. The hierarchical nanoflowers provide abundant active sites and enhanced mass transport, while the mixed Co²⁺/Co³ ⁺ valence states enable dual-functionality: Co³ ⁺ drives selective ethylene glycol (EG) oxidation in PET hydrolysate to formate (96.97% FE) via a glycolaldehyde-glyoxal pathway, and Co²⁺ optimizes hydrogen evolution reaction (HER, Tafel slope = 140 mV/dec). DFT calculations confirm Co³ ⁺ enhances *OCH₂CH₂OH adsorption (ΔE = -2.07 eV) for anodic oxidation, while Co²⁺ achieves near-thermoneutral ΔGH* (0.59 eV) for HER. In a coupled electrolyzer, Co₃O₄-F@NF simultaneously produces formate (90.50% FE) and H₂ at 1.4 V, outperforming Pt. Crucially, recovered terephthalic acid (PTA) shows high purity, enabling a net profit of $583.4/ton PET. This work establishes a sustainable paradigm for plastic waste upcycling and energy storage.

Nitrogen oxides (NOx) reduction is of great significance for further reducing both PM2.5 and ground-level ozone concentrations. Controlling nitrogen oxide emissions from coal-biomass cocombustion is an urgent challenge. This study develops a novel standalone Chemical Reactor Network (CRN) model to mechanistically elucidate the distinct nitrogen transformation pathways in cocombustion environments. This work reveals an enhanced bidirectional NO-N2O interconversion in the dilute phase, mediated through both direct NCO/NH radical routes and indirect pathways involving NO2 intermediates. The key distinction arises from biomass-volatile induced pathway switching: biomass-derived HCN significantly elevates NCO radical pools, establishing parallel NO-to-N2O conversion channels that create the characteristic emission profile of simultaneous NO reduction and N2O accumulation. Temperature exerts precise regulation, with NO-N2O conversion showing unidirectional characteristics in specific ranges, where higher temperatures promote NO formation via enhanced CH3 radical chemistry. Furthermore, the proposed biomass-coal balancing theory reveals that moderate blending ratios favor HCN → N2O conversion, reducing NO emissions, while excessive biomass shifts equilibrium toward HCN → NO pathways. This threshold behavior provides a theoretical foundation for targeted NOx control in multifuel combustion systems.

Modeling gas diffusion in porous adsorbents with disordered internal pore structures is inherently challenging. This study investigated on CO2 adsorption kinetic performance of moisture-swing adsorbents in direct air capture (DAC). The adaptability of the fractal theory was verified through the calculation of fractal dimension. A relationship between the effective porosity and the optimal specific surface area was proposed. Two kinetic parameters (diffusion coefficient D and reaction rate constant k) were derived and corrected based on the fractal theory. The improvement effects of the two were quantified at the theoretical level, and based on this, a quantitative optimization strategy for the hydrophobicity/pore structure of porous adsorbents was proposed. That is, the hydrophobicity optimization interval was 1.5-2.5 times the original, achieving an increase of 3-3.5 times in the reaction rate constant k. By constructing a regular hierarchical pore structure, the average pore diameter optimization interval is 30-60 nm, achieving an increase of 2-3 orders of magnitude in the diffusion coefficient D. Both the analysis of the conventional rate-limiting kinetic models and the fractal modified Thiele modulus indicated that the diffusion process was the dominant link restricting CO2 adsorption. The derivation of intrinsic parameters and the formulation of corresponding improvement strategies provide a theoretical foundation for the targeted synthesis and optimal design of adsorbent materials.

The valorization of plastic waste via electrocatalytic conversion into value-added chemicals and hydrogen represents a promising sustainable technology, yet is hindered by the lack of efficient and cost-effective bifunctional catalysts. Herein, we develop a hierarchically structured cobalt phosphide nanoflower catalyst anchored on nickel foam (CoP-F@NF) through fluoride-mediated morphology control. Comprehensive characterization confirms the successful synthesis of crystalline CoP nanoflowers with homogeneous elemental distribution. When applied to polyethylene terephthalate (PET) hydrolysate electro-oxidation, CoP-F@NF exhibits exceptional activity, high formic acid selectivity (>95 %) and Faradaic efficiency (>86 %), attributed to synergistic effects of the CoP phase and nanoflower architecture that optimize mass/charge transport (Tafel slope: 110.12 mV dec(-1)). Mechanistic studies reveal the dominant reaction pathway: ethylene glycol -> glycolaldehyde -> glyoxal -> formic acid. Simultaneously, CoP-F@NF demonstrates efficient hydrogen evolution reaction (HER) activity (Tafel slope: 117.7 mV dec(-1)), leveraging PET oxidation to replace energy-intensive oxygen evolution. In an integrated two-electrode system, CoP-F@NF achieves concurrent formic acid production (FE: >92 %, selectivity: >92 % at 2.0 V) and H-2 generation with superior stability over five cycles. Control experiments with CoO-F@NF and density functional theory calculations reveal that P-modulation elevates the Co d-band center (epsilon d = -1.295 eV vs. -1.601 eV for CoO), optimizing intermediate adsorption strength for both anodic oxidation (weakened *CHOCHO binding) and cathodic HER. This work establishes a noble metal-free route for plastic waste upcycling and green hydrogen production via electronic and morphological catalyst design.

Efficient utilization of lignocellulose is crucial for carbon emission reduction and decreasing reliance on fossil fuels. Building on a previously proposed methanol-based functional group protection strategy, which simplifies lignin-carbohydrate separation and prevents lignin condensation, this study thoroughly assesses its environmental impacts using life cycle assessment principles. Compared with that of six established pathways, the novel process can reduce composite environmental impact by up to 54%. Subsequently, integrated energy-environment-economy evaluation models were innovatively developed for an in-depth analysis. Across various comprehensive assessment frameworks, integrated modeling reveals certain ranking variations but enables robust decision-making. Notably, lignin valorization can enhance significant benefits of biorefineries. Corn-stover cellulosic biorefinery, which integrates lignin gasification-syngas fermentation to produce ethanol, and poplar cellulosic biorefinery, which integrates lignin depolymerization for antioxidants co-production, perform optimally. Finally, the study proposes optimization recommendations and underscores the importance of further research to develop innovative models or tools to improve the policy support system.

Focusing on enhancing the performance of the( 14)C method in determining biomass-coal co-combustion ratios, this study developed two novel sample preparation systems: a direct flue gas injection benzene synthesis system based on Liquid Scintillation Counting (LSC) and a direct flue gas sealing graphitization system based on Accelerator Mass Spectrometry (AMS). These systems reduced sample preparation time from 20-24 h to 6-8 h. Experimental validation showed relative errors in biomass blending ratios (1-40%) below +/- 4% for LSC and +/- 3% for AMS, except at the 1% blending condition. Compared with conventional methods, both accuracy and efficiency were significantly improved. An enhanced C-14-based industrial measurement scheme was established and successfully applied for monitoring biomass blending ratios (15-50%) in industrial facilities. Deviations between AMS and LSC were within +/- 3%, confirming the method's accuracy, despite discrepancies with the Distributed Control System (DCS) estimates. Additionally, predictive formulas for C-14 activity in biomass and air CO2 reduced economic investment, with relative errors from +/- 0.04% to +/- 3.25%. Overall, the new scheme improved accuracy by 50%, efficiency by 60%, and reduced detection costs by 60-80%, demonstrating feasibility and practical value for industrial applications.

Hydropyrolysis vapor upgrading (HP-VU) is a promising route for producing high-quality fuels from biomass, yet the migration of external hydrogen within the reaction network remains unclear. In this study, the reaction pathways of three guaiacyl phenolic compounds were investigated over a NiMo/gamma-Al2O3 catalyst during HP-VU. Product analysis coupled with D2 isotopic tracing were employed to elucidate hydrogen transfer mechanisms. It was found that during hydropyrolysis, hydrogen radicals from H2 dissociation preferentially attack the aromatic carbon bearing methoxy group, promoting the removal of methoxy group and creating internal methyl groups for alkylation. Subsequently, during catalytic vapor upgrading, external hydrogen moves between metal and acid sites in the form of Ni-H species. These species drive two competing pathways: direct deoxygenation to aromatics and hydrogenation-dehydration to cycloalkanes. Under D2 atmosphere, a pronounced kinetic isotope effect suppressed the direct deoxygenation route, thereby enhancing the selectivity to cyclohexane and methylcyclohexane. Deep deuterium incorporation, the presence of D2O, and deuterated light hydrocarbons confirmed that extensive H/D exchange and hydrogen migration occurred on the catalyst surface. These findings offer new insight into hydrogenation and deoxygenation pathways of lignin-derived compounds during HP-VU.

This study establishes an integrated framework that combines multi-method experimental kinetics with interpretable automated machine learning for predicting and elucidating the activation energy of biomass pyrolysis. Thermogravimetric analysis and kinetic modelling of three representative feedstocks (poplar, pine, corn straw) were performed using Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, Starink, Friedman, and Coats-Redfern methods. Gaussian multi-peak deconvolution clarified the stepwise decomposition of pseudo-components, revealing the thermal stability order: lignin > cellulose > hemicellulose. A robust, interpretable machine learning model was developed using the Fast Library for Automated Machine Learning based on a curated dataset of 1749 samples from 59 studies. The model achieved high prediction accuracy (test set: coefficient of determination = 0.74-0.89, Root Mean Square Error = 19.01-27.75 kJ/mol) and identified conversion degree, nitrogen, hydrogen, and lignin content as the dominant features governing activation energy. SHapley Additive exPlanations analysis, three-dimensional partial dependence plots, and interaction analysis further quantified nonlinear feature interactions, revealing that high hydrogen and lignin contents synergistically elevate activation energy, whereas high oxygen content mitigates lignin's stabilizing effect. This work bridges component-specific kinetic analysis with explainable machine learning, providing both a predictive tool and mechanistic insights for the targeted optimization of biomass pyrolysis.

Lignin catalytic hydropyrolysis has garnered significant interest for its potential to convert lignin into valuable biofuels and chemicals. However, the underlying mechanisms of this process, particularly the role of catalysts and hydrogen influence reaction pathways and product distribution, has not yet been fully elucidated. This study aims to address these gaps by investigating the mechanism of lignin catalytic hydropyrolysis with a nickel catalyst, employing both experimental and simulation approaches. Experimental results demonstrated that the catalyst effectively promoted demethylation and hydrodeoxygenation, with increased hydrogen pressure further facilitating C-O bond cleavage and enhancing hydrodeoxygenation. Simulation results revealed that both the catalyst and elevated temperature promoted C-C and C-O bond cleavage in lignin, accelerating reactant decomposition and the formation of light weight products. It was found that while a moderate increase in hydrogen pressure facilitated hydrodeoxygenation of liquid products, excessive pressure suppressed bond cleavage, thereby hindering further enhancement of liquid product quality. Notably, the simulations provide direct evidence that high-pressure hydrogen mitigates catalyst deactivation by suppressing carbon accumulation. This study highlights the complex interplay between temperature, hydrogen molecules, and the catalyst during lignin catalytic hydropyrolysis. This approach offers insights into lignin catalytic hydropyrolysis and supports the development of efficient catalysts for biomass conversion.

This study investigates the co-combustion dynamics of biomass-derived syngas and coal in a 600 MW tangential pulverized coal (PC) boiler through integrated experiments and numerical simulations, with a focus on NO emission mechanisms and operational optimization. Besides, this paper treats biomass gasification gas as a core process parameter, comprehensively investigating and elucidating the effects of various common operating conditions-including gas flow rate, injection location, and boiler loads-on boiler performance and pollutant formation characteristics. Key findings reveal that NO concentration profiles along the furnace height exhibit a multi-stage trend: initial increase due to volatile nitrogen release and thermal NO formation, followed by reduction in transition zones via homogeneous/heterogeneous reactions, and a final stabilization as fuel-NO dominates. Introducing biomass syngas enhances post-SOFA zone temperatures while advancing coke nitrogen release and amplifying NO reduction through gas-phase reactions, ultimately lowering total NO emissions by 8.03 % compared to pure coal combustion. Notably, reduced boiler load intensifies the syngas-induced NO reduction effect (up to 7.3 % at 13 % load) due to prolonged NO reduction residence times and enhanced gas-solid interactions. Optimal performance is achieved at 6-8 % biomass thermal ratio, with lower injection positions maximizing utilization of transition zone reductants, thereby suppressing 8 % of peak NO formation. These results establish actionable strategies for emission control, demonstrating that strategic biomass syngas integration enables simultaneous NOx mitigation (248 -> 191 mg/Nm3) and operational flexibility across load ranges, providing critical insights for retrofitting conventional coal boilers toward sustainable co-firing systems.

The ultralow atmospheric partial pressure of CO2 (similar to 40 Pa) presents a significant challenge for direct air capture (DAC). In this study, high-performance porous aerogel adsorbents are prepared using the unidirectional freezing-ice-templating method. The dispersion of the mixed solution is effectively improved by particle size modulation, and functionalized materials with abundant gas channels are constructed by the rapid cooling of liquid N-2. The adsorbents feature a cross-structure comprising monolayer active components and nanoscale layered carriers. The unique micro/mesoporous composite structure of the adsorbents facilitates gas-phase transport. When the functional group efficiency is increased by 5.8 times, the prepared adsorbents demonstrate excellent CO2 capture capacity (1.17 mmol/g and 148 mol/m(3)) and a low adsorption half-time (1.28 min). The unique cross-structure of the adsorbents renders them hydrophobic; thus, they show higher adsorption capacity at high humidity than other moisture swing adsorbents. At the molecular scale, quantum chemical calculations show that appropriate coordination between the active components and carriers enhance the water vapor hindering ability of the adsorbents. The developed aerogel adsorbents significantly expand the application scenarios for moisture swing adsorbents and enhance the efficiency of DAC.

To achieve efficient and clean utilization of biomass fuels in high-altitude regions, understanding the effects of low-pressure and low-oxygen conditions on their combustion characteristics is crucial. This study investigates the combustion characteristics of yak manure under simulated high-altitude conditions using a concentrating photothermal combustion system. A high-speed camera, thermocouples and a flue gas analyzer were employed to monitor particle behavior, temperature and flue gas components during combustion. Devolatilization products (chars) were analyzed using nitrogen adsorption/desorption, Electron Paramagnetic Resonance (EPR), and Raman spectroscopy. Results reveal that low pressure enhances the volatiles release by promoting side chain cleavage and aromatic structure formation, increases the char porosity and stable free radical concentration, and decreases the char specific heat capacity. These changes lead to higher combustion temperatures, earlier ignition and faster burnout. In contrast, low oxygen levels inhibit reactions with volatiles and char, resulting in delayed ignition and lower peak temperatures. When both low pressure and low oxygen conditions are applied simultaneously, compared to atmospheric combustion, an earlier and lower peak concentration of CO and NO emissions is detected. Additionally, slight reductions in ignition and burnout times, along with increased combustion temperatures, are observed, indicating a combined effect dominated by low pressure. These findings provide essential insights for the efficient use of biomass fuels in high-altitude regions.

Studying chemical production from biomass is essential for developing sustainable and eco-friendly alternatives to fossil-derived chemicals, reducing greenhouse gas emissions, and promoting a circular bioeconomy. In this study a new biomass upgrading route was proposed including extraction of phenolic fraction followed by catalytic hydroconversion and then dehydration to olefins. The conversion of bio-oil fraction into olefins was developed using a continuous-flow setup with two reactors for tandem hydrogenation - dehydration process (225 degrees C in the 1st reactor with 2 % Ru over titanosilicalite-1 (TS-1) catalyst, 160 degrees C in the 2nd reactor with BEA catalyst, 5 MPa H2, LHSV 1.5 h- 1 ). The optimized mild conditions were determined for each stage of the catalytic conversion process, which allowed us to obtain cyclohexene from bio-oil-derived compounds with a selectivity of up to 70 %. The olefin fraction was further transformed to silicon-organic chemicals via hydrosilylation on Pt catalyst. Using in situ DRIFT technique and in situ X-ray absorption spectroscopy (XAS) we determined the mechanism of selective hydrodeoxygenation and evolution of Ru species.

Co-processing bio-oil with petroleum fractions in existing petrochemical refining facilities is a promising approach for the low-carbon transition of the petrochemical industry. However, the high oxygen content, viscosity, and acidity of crude bio-oil limit its compatibility with conventional refining infrastructure. In this study, we reported a strategy for co-processing high-quality bio-oil, obtained via catalytic fast hydropyrolysis (CFHP) with straight-run gas oil (SRGO). A cost-effective metal oxide catalyst, NiMo/TiO2, was selected as an optimal catalyst achieving an optimal balance between deoxygenation efficiency and carbon yield. CFHP was also conducted in a continuous-flow reactor, yielding 40.08 C% yield of C4+ products while maintaining a low oxygen content of 7.34 wt%. The resulting bio-oil with improved quality can be blended with SRGO at a high ratio of 15 vol% without compromising catalyst performance during co-processing.

Direct air capture (DAC), postcombustion capture (PCC), and CO2-to-methanol technologies utilizing renewable energy are increasingly recognized for reducing CO2 emissions and producing high-value chemicals. To enhance economic feasibility, the integration of the CO2 capture and methanol synthesis (IN-CC-MS) has been demonstrated using dual-function materials. Currently, economic savings associated with integrated processes are controversial. In this work, a comprehensive techno-economic analysis for IN-CC-MS processes using in situ reactors with a shortcut model was implemented with optimization methods. Compared with tandem CO2 capture and methanol synthesis (TD-CC-MS) processes, the results show that the levelized cost of methanol (LCOM) for IN-PCC-MS processes decreases by 7.73%, while it increases by 17.04% with low adsorbent working capacity (1 mol/kg-ads). Conversely, IN-DAC-MS systems experience an LCOM increase ranging from 15.98 to 69.45%, primarily due to a larger increase in heating consumption and CAPEX caused by in situ reactors. Moreover, IN-DAC-MS processes exhibit a lower LCOM under mild hydrogenation conditions. These results indicate that in situ layouts for DAC-MS processes face economic challenges, hinging on adsorbent/catalyst performance, reactor parameters, and operation conditions. By 2050, in situ processes are expected to be economically feasible with declining hydrogen price and increasing methanol price. These findings provide novel insights into ICCU technologies.

The high viscosity and oxygen content of pyrolysis crude oil hinder the advancement of pyrolysis technology. To address the issue, this study conducted hydrodeoxygenation upgrading experiments on pyrolysis crude oil using hydrothermal directional conversion. A variable analysis was performed to assess the differences in upgrading effects based on the active metal (Ru, Pt) and the supports (activated carbon, Nb2O5, MgO) of the supported catalyst, and further investigations were conducted on the catalyst with bimetallic doping modification. Optimal reaction conditions were determined by adjusting the reaction temperature. Additionally, directional conversion studies of model compounds were carried out to elucidate the reaction pathway. The results indicated that the Pt/MgO catalyst achieved the highest yield of stable and combustible compounds (hydrocarbons, alcohols, ethers, esters, and ketones), with a yield of 17.8 wt%. Upon modification with Ni doping, the yield increased by 49.5%. The upgrading effect improved with an increase in reaction temperature, and the yield of target compounds was 26.7 wt% at 290 °C, with an energy conversion rate of 72.6% and a selectivity of 75.8%. Moreover, the physicochemical properties of the upgraded oil were similar to those of ethanol. All three model compounds underwent 100% conversion. This study provides both experimental support and a theoretical foundation for the further development of biomass conversion technology.