Hydrogen is considered a promising clean energy carrier for sustainable energy systems. Catalytic methane decomposition (CMD) provides a COx-free pathway for hydrogen production while simultaneously generating valuable carbon nanostructures. In this study, Ni-supported activated carbon (AC) catalysts were synthesized using three different preparation methods: wet impregnation (WI), sonicated wet impregnation (SWI), and hydrothermal (H) synthesis. The catalytic performance of the prepared catalysts (30Ni/AC) was evaluated in a fixed-bed reactor at 850 °C with 40% methane (CH4) at a gas hourly space velocity (GHSV) of 12,000 mL/h.gcat. Structural and morphological properties of fresh and spent catalysts were investigated using XRD, SEM, TEM, EDX, and Raman spectroscopy. The hydrothermal catalyst exhibited the smallest Ni crystallite size (~20 nm) and the highest initial methane conversion (~77%), followed by the SWI catalyst (~73%). Both catalysts demonstrated higher hydrogen production rates and improved catalytic stability compared with the WI catalyst, which showed rapid deactivation due to larger crystallite size and carbon encapsulation. Structural analyses confirmed the formation of graphitic carbon nanotubes with varying degrees of crystallinity. Overall, the study highlights the strong influence of catalyst preparation method on metal dispersion, catalytic activity, and carbon quality during methane decomposition.
Coal tar pitch, a low-cost industrial byproduct with high carbon yield, is a superior precursor for hard carbon. Pre-oxidation and carbonization are two core procedures for pitch-derived hard carbon, yet most previous works focus on pre-oxidation while neglecting carbonization optimization. Conventional slow carbonization using a muffle furnace lacks flexibility in tailoring interlayer spacing, intrinsic defects, and closed pores, thus limiting the improvement of electrochemical performance of hard carbon. Herein, Joule heating flash carbonization is employed to treat pre-oxidized coal tar pitch at 1300 °C. This strategy effectively immobilizes pyrolytic free radicals and promotes ester group formation, meanwhile increasing structural defects, expanding the carbon interlayer spacing, enlarging the closed pore size (from 1.69 to 1.97 nm) and increasing the closed pore volume (from 0.037 to 0.122 cm3 g−1). These structural advantages collectively accelerate Na+ diffusion, enrich active adsorption sites and boost pore-filling capacity. The increased surface activity also induces more electrolyte decomposition and forms a thicker solid electrolyte interphase (SEI), leading to a slight decline in initial Coulombic efficiency (ICE). The resultant HC@F delivers a reversible specific capacity of 328.4 mAh g−1 at 0.1 C with an ICE of 83.9%, and an excellent rate performance of 245.4 mAh g−1 at 4 C, while maintaining good capacity retention of 84.3% over 2500 cycles. Multiple in-situ and ex-situ characterizations verify the “adsorption-intercalation-pore filling” sodium storage mechanism. This work reveals that flash carbonization regulates pitch-based hard carbon, offering a facile thermal strategy for high-performance, low-cost anodes in practical sodium-ion batteries.
Dry reforming of methane (DRM) converts primary greenhouse gases (CH4 and CO2) into valuable syngas, offering a critical pathway toward achieving global carbon neutrality. However, conventional high-temperature thermocatalysis persistently suffers from severe carbon deposition and rapid metal sintering. Photothermal catalytic DRM (PDRM) effectively overcomes these fundamental limitations by synergistically coupling photonic and thermal energy inputs, thereby significantly lowering apparent activation energies and sustaining long-term operational stability. While recent literature heavily emphasizes macroscopic reactor engineering and techno-economic modeling, this review provides a distinctive, bottom-up deconstruction of PDRM catalysts ranging from atomic precision to macro-structural functionalization. We systematically clarify the dual-path (photochemical and photothermal) synergistic mechanisms and critically analyze active site engineering, spanning the electronic modulation of precious metals, cost-effective non-precious metal alloying, and maximum atom utilization in single-atom catalysts. Furthermore, we highlight the pivotal role of active site-support interactions, specifically dissecting how dynamic defect engineering, precise pore engineering, and robust confinement effects within diverse core-shell nanostructures inherently suppress catalyst deactivation pathways. Finally, we highlight essential future commercialization frontiers such as full-spectrum responsive materials, multi-field coupled reactors, and rigorous lifecycle assessments to accelerate the industrial-scale deployment of highly efficient DRM technologies
Sugarcane vinasse, a by-product of ethanol industries, is rich in organic matter and salts. While its environmental release as wastewater causes considerable pollution, it also represents a viable feedstock for valorization through microbial fermentation, a potential explored herein. The study evaluated the acidogenic potential of bovine ruminal microbiota on vinasse supplemented with dried domestic organic waste (DDOW) under different temperature conditions (25 and 39 °C), substrate sterility, and oxygen availability (oxic and microoxic). Changes in pH values were monitored over 28 days, and the results showed that non-sterile vinasse with DDOW at 39 °C achieved the most significant pH reduction, from an initial 4.1 to 3.8 under microoxic conditions. Response surface methodology (RSM) was applied to optimize sterile vinasse- and DDOW concentrations, and incubation time to achieve maximum volatile fatty acids (VFA) production, demonstrated by pH reduction. Statistical optimization analyses showed that the optimal vinasse- and DDOW amount, to achieve significant pH decreases (p < 0.001), was found at concentrations of 102 g L−1 and 20 g L−1, respectively. Total VFA were measured by High Performance Liquid Chromatography (HPLC) during the incubation period, and there was an increase from 14.8 ± 2.5 g L−1 to 27.3 ± 0.9 g L−1 after 28 days of incubation. The concentration of four essential amino acids after 28 days of inoculation showed notable variation, among them tyrosine exhibited the most pronounced increase (1.47-fold) and lysine also increased considerably (1.23-fold). Isolation of microorganisms and microscopic examinations confirmed the presence of diverse morphotypes of acidogenic bacteria and yeasts. Re-inoculation experiments with isolated microorganisms highlighted that a diverse microbial community and its interactions drive acidogenic activity. Metabarcoding analysis showed the microbial shift from Bacteroidota to Bacillota in inoculated sterile vinasse. These results demonstrate that bovine rumen microbiota can efficiently convert the acidic composition of the vinasse and increase total VFA production, providing a basis for its sustainable valorization.
Ethyl lactate can be produced from bio-derived feedstock such as ethanol and lactic acid via a catalytic esterification reaction. Here, TiO2-Al2O3 support was employed as a catalyst, synthesized by mixing derived precursor Al (aluminum isopropoxide) and Ti (titanium tetraisopropoxide), and acid treatment (H2SO4 and H3PO4), followed by loading of tungsten. The WO3 supported on H2SO4 or H3PO4-modified TiO2-Al2O3 were then evaluated in terms of improving catalytic performance and durability. The catalysts were characterized by X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET), scanning electron microscopy–energy dispersive X–ray spectroscopy (SEM–EDX), and X-ray photoelectron spectroscopy (XPS). The reaction was carried out at 80 °C for 4 h in a batch system. The findings highlighted in particular that 0.5 M of H2SO4 treated WTA highly enhanced the yield of ethyl lactate (57.15%) and reusability over three cycles. The sulfation leads to higher medium to strong acid sites (332.8 μmol/gcat) and increased surface area (130.1 m2/g), also increasing oxygen vacant sites. The catalyst stability declined upon structural degradation over three cycles, which might be attributed to acid site loss and leaching of W and Al. However, the WO3 supported on 0.5 M H2SO4-modified TiO2-Al2O3 maintained superior long-term reusability compared with Amberlyst-15. These findings provide crucial insights into catalyst design strategies, optimizing acid functionality and structural stability for esterification reactions.
Biogas is a promising renewable energy source, but conventional CO2 removal technologies are costly and energy-intensive, limiting widespread adoption. Biological CO2 conversion into acetic acid by acetogenic bacteria via the Wood-Ljungdahl (WL) pathway offers a sustainable alternative for simultaneous biogas upgrading and carbon valorization. However, slow autotrophic growth and low productivity remain critical bottlenecks. Biochar derived from agricultural residues has shown potential to enhance microbial fermentation; however, its role in biological CO2 fixation to acetic acid has not been investigated. This study evaluated sugarcane leaf biochar (BSL) and bagasse biochar (BSB) for enhancing CO2 conversion to acetic acid by Clostridium thailandense. BSL demonstrated superior performance, achieving rapid H2 consumption (89.8% within 48 h vs. 0% for controls) and upgrading biogas from 38.4% to 84.2% CH4 content while producing 2.0 g/L acetic acid. BSL's higher Fe content (2.1-fold compared to BSB) and superior pH buffering capacity were associated with enhanced bacterial performance, with optimal loading at 15 g/L. Genome-based analysis identified putative transport systems for Fe, Ca, and Mg, suggesting the capacity of C. thailandense to utilize mineral species released from BSL. These minerals may support acetogenic metabolism by supplying physiologically relevant cofactors and by contributing to cellular stability and relief of acid stress, which is consistent with the enhanced biogas upgrading performance observed under BSL supplementation. Overall, BSL represents a promising low-cost functional material for enhancing biological biogas upgrading and acetic acid production through improved mineral availability and fermentation stability.
The utilization and conversion of carbon dioxide is a key strategy for achieving the “Dual Carbon” goals. The heterogeneous catalytic hydrogenation of carbon dioxide has predominantly centered on the synthesis of low-carbon olefins. However, the transformation of CO2 into high-carbon unsaturated hydrocarbons (HCUHCs) holds significantly greater practical relevance and economic potential. The paper systematically reviews the latest advancements of Fe-based and Co-based catalysts in the hydrogenation of CO2 to produce HCUHCs, such as C5+ alkenes and aromatic hydrocarbons. It focuses on analyzing the structure-performance relationship of the catalysts. The reaction pathways and mechanisms of CO2 hydrogenation were first determined, followed by a detailed discussion on active phases in Fe-based and Co-based catalysts. The regulatory effects of promoters and supports on the selectivity and catalytic stability were analyzed. This review can help researchers better understand the mechanism and application of CO2 catalytic conversion.
Household food residues (HFRs), a substantial yet underexplored fraction of lignocellulosic waste, were evaluated as potential substitutes for conventional substrates (wheat straw-WS and barley straw-BS) in the process of P. ostreatus basidiocarps cultivation. Prior to basidiocarps cultivation, the lignocellulosome was profiled during solid state fermentation of WS and BS supplemented with HFRs (almond seed coats, peanut shells, spent espresso grounds, spent immuno mix tea or spent milk thistle seeds). Laccases were dominant in the ligninosome, with a peak activity (9260.52 U/L) measured after fermentation of wheat straw mixed with spent espresso grounds. Xylanases were dominant in the P. ostreatus hemicellulosome, with activities exceeding 2000 U/L observed on several HFRs supplemented substrates. Although the highest delignification rates were recorded on pure WS and BS (about 70%), their substitution with spent espresso grounds slightly decreased delignification levels, while hemicellulose removal was increased by HFRs. Rapid substrate colonization and basidiocarps formation were observed on all tested substrates. The highest yields (169.95 g/kg and 156.91 g/kg) and biological efficiencies of cultivation (89.33% and 85.33%) were recorded on BS-based substrates. The structure of the spent substrates and obtained basidiocarps was characterized using Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). These results demonstrate the strong potential HFRs for conversion into P. ostreatus basidiocarps through sustainable and commercially relevant cultivation strategies.
Photocatalytic conversion of carbon dioxide (CO2) into value-added fuels and chemicals is commonly considered as one of the promising solutions to reducing greenhouse gas emissions and at the same time, to make carbon recycling a viable solution in the energy infrastructure of the future. Nevertheless, the effective application of CO2 photoreduction is still limited by low quantum efficiencies, poor product selectivity, and stability problems. These problems are inherently connected with the design of the underlying catalyst. Specifically, catalyst structure and band alignment interplay play a critical role in controlling light harvesting, charge generation and separation, CO2 activation and surface reaction pathways. In recent developments, the combination of structural design and specific band modulation engineering is shown to be used rationally to provide unprecedented chances to overcome the existing efficiency bottlenecks and provide selectivity in products. The synergetic roles of the two factors on catalytic performance are still crucial to the process of fast-tracking the formation of the next generation of photocatalysts. This review specifically focuses and comprehensively discusses catalyst structural design, band engineering strategies, characterization techniques, computational methods, and their combined impact on CO2 photoreduction performance and selectivity towards scalable energy conversion systems.
Formic acid (FA) is regarded as a potential liquid organic hydrogen carrier due to its relatively high hydrogen density and stability. It is crucial to explore efficient, stable and recyclable non-precious metal heterogeneous catalysts to achieve efficient and highly selective dehydrogenation of FA. Herein, biomass waste-derived γ-Mo2N catalyst is prepared by one-step pyrolysis, which from waste egg liquid by solid reaction with ammonium molybdate (AHM) for addition-free FA dehydrogenation. The results show that the E-Mo2N-0.05-750 catalyst produced with a weight ratio of AHM to waste egg of 0.5/10 with the pyrolysis temperature of 750 °C exhibits the best performance. The catalyst achieves a 388.3 mL/gcat./h gas production rate and the dehydrogenation selectivity over 99% in the additive-free aqueous FA with a high concentration (40 vol.%). Meanwhile, the catalyst demonstrates good stability during five consecutive cycles and the long-term test (45 h).
The intrinsic catalytic activity of single-atom catalysts (SACs) can be enhanced by incorporating other elements. However, understanding the roles of these heteroatoms is crucial for maximizing catalytic efficiency. In this study, we focused on the electrochemical CO2 reduction reaction (CO2RR) over Ni-based dual-atom catalysts (DACs) containing Zn or Mn using in situ Raman spectroscopy and ab initio molecular dynamics simulations. The NiZn DAC achieved a CO faradaic efficiency of > 99.8% up to a current density of − 300 mA cm−2. Compared with the Ni SAC and NiMn DAC, the NiZn DAC more effectively facilitated electron transfer by tuning the electronic structure of the catalytically active Ni center, stabilizing the chemisorbed CO2 intermediates, and accelerating proton transfer by biasing the electron density of the chemisorbed CO2 intermediates. This study provides insights into the roles of heteroatoms in catalytic activity and will aid the development of highly efficient catalysts.
Carbon nanostructures are emerging as advanced functional materials for pharmaceutical removal from wastewater. In this study, N-doped multi-walled carbon nanotube (N-MWCNT) hybrids were synthesized via CVD using an Fe catalyst at 750 °C for 1–3 h to degrade ibuprofen (IBF). The 3-hour sample (CN3) showed the best performance, with a high surface area (205.4 m2/g) and pore volume (0.824 cm3/g), achieving 92% IBF removal under 300 W VL irradiation for 60 min. Increasing CN3 dosage from 10 to 40 mg further enhanced degradation. Stability tests revealed only a 3% decline in efficiency after four cycles, indicating excellent durability. Scavenger and EPR analyses indicate O2•− is the dominant oxidizing species, with •OH contributing secondarily under visible-light irradiation. These findings highlight synthesis conditions’ critical role in photocatalytic activity
Improving the dispersibility and recoverability of powdered catalysts is essential for developing efficient and cost-effective photocatalytic systems. Herein, silver-loaded β-FeOOH/quaternized cellulose nanofibrils composite hydrogel, denoted as Ag@β-FeOOH/QCNF, was successfully prepared via an in-situ synthesis approach combined with photodeposition for environmental remediation. The composite hydrogel consisted of a three‑dimensional porous network, with β-FeOOH photocatalysts and Ag nanoparticles uniformly distributed. The composite hydrogel not only exhibited adsorption capacity toward organic pollutant but also established multidimensional electron‑transport pathways that facilitated the migration of photo-generated charge carrier, thereby significantly enhancing light-harvesting efficiency. The synergistic effect between adsorption and photocatalysis enabled hydrogel to achieve nearly complete degradation of tetracycline (100%) within 30 min under simulated visible light, while maintaining a removal efficiency above 94% over five consecutive cycles, demonstrating outstanding stability and reusability. Free radical scavenging experiments demonstrated that ·OH and h+ were the primary reactive species responsible for pollutant degradation. Overall, this study presents a straightforward approach to construct 3D network-structured hydrogel materials with efficient photocatalytic performance, which holds significant potential for applications in water purification.
Polyhydroxybutyrate (PHB), a biodegradable polymer, offers a promising eco-friendly alternative to petroleum-based plastic. Cupriavidus necator is a well-known PHB producer that can accumulate about 80% of PHB of its dry cell weight. However, the high cost of carbon sources remains a major barrier to commercial-scale production. Waste cooking oil (WCO), being rich in carbon and abundantly available, represents a low-cost substrate for PHB biosynthesis. In this study, C. necator DSM428 was used to convert sunflower oil-based waste cooking oil (SF-WCO) to PHB, and process optimization was performed by examining the effects of phosphorus limitation, SF-WCO concentration (2–10%), nitrogen source (ammonium sulfate, sodium nitrate, ammonium nitrate, ammonium chloride, peptone, urea, and yeast extract), and incubation time (24–120 h) on PHB production. Results demonstrated that C. necator DSM428 could efficiently metabolize SF-WCO, achieving a PHB accumulation of 22.88% under initial conditions. Optimization revealed that the best conditions for PHB production were 0.04% of phosphorus, 2% SF-WCO, yeast extract as a nitrogen source, and 72 to 96 h of incubation. Under these conditions, PHB concentration reached 6.75 g/L, biomass 7.42 g/L, and the maximum PHB accumulation was 93%, the highest reported for this strain. Characterization analysis of the produced PHB showed similar properties to the standard PHB. Overall, the findings confirm that the SF-WCO is an effective substrate for PHB production, with potential for industrial-scale application following further optimization.Abbreviations: PHB, Polyhydroxybutyrate; WCO, Waste cooking oil; SF-WCO, Sunflower oil-based waste cooking oil; FAME, Fatty acid methyl ester; PV, Peroxide value; AV, Acid value; GC–MS, Gas Chromatography-Mass Spectrometry; FTIR, Fourier Transform Infrared Spectroscopy; NMR, Nuclear magnetic resonance; DSC, Differential Scanning Calorimetry.
Cassava pulp (CP), a lignocellulosic side stream from starch extraction, is generated at approximately 2.5 tons per ton of starch, creating significant disposal challenges for the industry. Although anaerobic digestion (AD) offers a promising valorization pathway, the complex structure of CP limits microbial accessibility during hydrolysis and acidogenesis, the upstream stages that dictate overall AD performance. Kinetic parameters for CP bioconversion remain largely unexplored, particularly for Clostridium manihotivorum CT4T (CT4T), a hydrolytic–acidogenic bacterium not previously studied for CP bioconversion kinetics. In this study, the degradation kinetics of individual CP components (cassava starch, cellulose, and hemicellulose) were systematically compared with actual CP using CT4T. The strain displayed the highest maximum specific growth rate (μmax) on CP, with a μmax of 0.155 1/h, compared with 0.141 1/h on cassava starch, 0.027 1/h on cellulose and 0.032 1/h on hemicellulose. At 15 g/L initial CP, CT4T achieved 66.75% overall degradation, complete starch utilization, and a final biomass concentration of 4.43 g/L. Kinetic modeling showed strong agreement with experimental observations (R2 > 0.90), while carbon balance analysis indicated high recovery (90.04–95.47%), confirming metabolic consistency. Butyric acid (BA) was the predominant fermentation product across all substrates. Simulations based on individual component kinetics consistently overestimated CP highlight the influence of substrate interactions and structural complexity in real biomass systems. Overall, this study provides quantitative kinetic parameters describing the hydrolysis and acidogenesis of CP mediated by CT4T, contributing critical data for improved modeling and the design of hydrolysis-focused or two-stage bioprocesses for CP valorization.
This study investigates the valorization of recycled carbon black (rCB) recovered from end-of-life tires by vacuum pyrolysis through in situ surface functionalization via a new catalytic ethylene oligomerization. Short polyethylene-like chains are grafted directly onto the rCB surface, transforming an inherently incompatible, low-value recycled filler into a functionalized reinforcing agent modified for integration into a bio-based polymer matrix. The functionalized rCB (rCB-F) is incorporated into an eco-friendly thermoplastic composite using bio-based high-density polyethylene (Bio-HDPE) derived from sugarcane and characterized by a low carbon footprint. The particle size distribution and morphology of both commercial carbon black (cCB), recycled carbon black (rCB), and functionalized recycled carbon black (rCB-F), were characterized using laser diffraction, scanning electron microscopy, and transmission electron microscopy. Composites containing 3 wt% and 15 wt% CB were manufactured and analyzed using X-ray diffraction, differential scanning calorimetry, mechanical testing, and microscopy techniques. The results indicate that both filler type and concentration affect crystallinity, lamellar structure, and mechanical properties. Notably, the bio-composite containing 15 wt% rCB-F exhibited a 45% increase in tensile modulus and a 14% increase in hardness relative to neat Bio-HDPE. Crystallinity measurements obtained from both XRD and DSC were correlated with tensile performance, highlighting the influence of differences between the two analytical techniques. These findings suggest that rCB-F provides a sustainable reinforcement alternative to fossil fuel-derived cCB, offering competitive performance in environmentally responsible composite material applications.
Detecting metal ion pollutants at low concentrations requires high sensitivity and selectivity, posing a significant challenge. Carbon dots have emerged as a successful substrate, demonstrating their efficacy in sensing a wide range of metal ions, including iron, mercury, cadmium, aluminum, lead, and many others. Carbon dots that are functionalized with oxygen ligands, including hydroxyl and carboxylic acid, exhibit distinct sensitivity to metal ion pollutants. Furthermore, carbon dots doped with elements such as nitrogen, sulfur, and phosphorus have featured prominently in numerous studies focused on detecting metal ions. Theoretical studies have proven to be a valuable tool in understanding the sensing mechanism of CDs for metal ion pollutants. Through computational simulations and calculations, we reviewed the complex interactions between CDs and metal ions at the molecular level, revealing the underlying principles that control the sensitivity and selectivity of CDs towards specific metal ions. In this review, we examine the mechanisms, sensing, and computational modeling that underlie carbon dot metal ion sensing capabilities. These CD-based sensors will continue to make significant contributions to real life applications covering environmental, industrial, biomedical diagnostics, and therapeutics fields.
This study evaluates the biological conversion of starch-based waste into value-added organic acids and ethanol using a native rumen consortium microbiota (RCM) and its enriched counterpart (IRCM), focusing on how inoculum conditioning influences carbon flux, product selectivity, and conversion efficiency. Inoculum preparation resulted in a lower initial pH in IRCM compared to RCM, suggesting that starting pH, including pretreatment carryover effects, may impose a first-order constraint on microbial community trajectories and product profiles. Batch fermentations were conducted at 10, 15, and 25 g/L starch, as well as at 100 g/L under a substrate shock (high organic loading) condition. Results showed that RCM exhibited more vigorous acidogenic activity, producing up to 5.1 g/L lactate and 2.7 g/L acetate, with respective yields of 0.33 g/g and 0.24 g/g. In contrast, IRCM showed lower overall acid production and a relative shift toward ethanol formation. However, the absolute ethanol concentration increased only moderately (1.03 g/L in IRCM versus 0.83 g/L in RCM at 10 g/L substrate, corresponding to ∼24% higher concentration), and ethanol accounted for a larger fraction of total soluble products due to reduced acid synthesis. A significant interaction between inoculum type and substrate load was observed (p < 0.001). At a moderate substrate concentration (25 g/L), compared with the high organic loading condition (100 g/L), RCM supported balanced redox metabolism, achieving approximately 5.1 g/L lactate and 2.7 g/L acetate with around 35% carbon recovery, indicating integrated hydrolytic and fermentative processing under increasing substrate load. Conversely, enrichment in nutrient-defined medium altered metabolic behavior and reduced overall conversion performance. Overall, RCM demonstrated robust, low-cost biocatalytic capability for the acidogenic valorization of starch waste, with higher acid yields and a broader product distribution than IRCM. These findings advance the understanding of rumen-based mixed-culture fermentation and highlight its potential as a biological carbon-conversion strategy within low-carbon and circular bioresource frameworks.
This study systematically investigates the synthesis of mesoporous δ-Al2O3 supports via a controlled sol–gel method and their application in NiMo-catalyzed hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). Advanced characterization reveals that the textural and acidic properties of the δ-Al2O3 supports can be precisely tailored, which subsequently modulates the metal-support interaction, governs the sulfidation behavior, determines the active phase morphology, and ultimately regulates the HDS performance. Among the series, the catalyst supported on δ-Al2O3 aged at 50 °C (denoted as NiMo/δ-50) demonstrated an optimal combination of high surface area, large pore volume, and moderate acidity. This optimal support structure, accompanied by an appropriate metal-support interaction, facilitated the formation of a highly active phase characterized by a superior Mo sulfidation degree (69%), a high proportion of NiMoS sites (90.2%), and MoS2 slabs with optimal stacking. Consequently, this catalyst achieved outstanding HDS activity, with near-complete DBT conversion (99.9%) and 94.3% conversion of the sterically hindered 4,6-DMDBT. This work underscores the pivotal role of support engineering in regulating metal-support interaction and provides a rational design strategy for advanced HDS catalysts.
The growing global demand for clean and sustainable energy has intensified the search for renewable alternatives to fossil fuels, with lignocellulosic biomass emerging as one of the most abundant and environmentally favorable resources. As a carbon–neutral feedstock available from agricultural, forestry, and industrial residues, lignocellulosic biomass supports the production of diverse biofuels, including biodiesel, bioethanol, biogas, and biohydrogen. However, its complex and recalcitrant structure, dominated by tightly interlinked cellulose, hemicellulose, and lignin, requires efficient catalytic systems to enable effective bioconversion. Biocatalysts, including lignocellulolytic enzymes and engineered microorganisms, play a central role in overcoming these structural barriers by enhancing hydrolysis, saccharification, and fermentation processes. Recent innovations in pretreatment methods, enzymatic technologies, microbial engineering, and consolidated bioprocessing have significantly improved the efficiency and sustainability of lignocellulosic biofuel production, though challenges remain in cost, enzyme stability, and process integration. This review provides a comprehensive examination of lignocellulosic biomass composition, the structural barriers limiting its conversion, and the current landscape of biocatalyst-driven technologies for biofuel production. Emphasis is placed on enzymatic hydrolysis, fermentation strategies, anaerobic digestion, and emerging integrated platforms that streamline processing and reduce operational complexity. By analyzing recent progress and existing limitations, this review outlines pathways toward economically viable, environmentally sustainable biofuel systems that support the broader transition to renewable global energy solutions.
