Ni-based catalysts serve as a momentous candidate for syngas production from dry reforming of methane (DRM), which is limited due to the serious sintering and carbon deposition. Herein, we demonstrated two attapulgitebased ZSM-5 (AZ) supported Ni-Sm bimetallic catalysts, and systematically compared the influences of Sm spatial distribution including surface dispersion and skeleton incorporation on catalyst microstructure. Importantly, it was elucidated that adding Sm could create abundant Sm3+-O2- pairs and oxygen vacancies, and promote to the construction of electron-rich metallic Ni sites via Ni-O-Sm electronic interaction. Due to the highest concentration of active centers consisted of electron-rich metallic Ni sites, Sm3+-O2- pairs and oxygen vacancies, the surface dispersion of Sm contributed to the highest initial CH4/CO2 conversions of 84.3 % and 84.4 % in NiSm/AZ. Notably, Sm incorporated into zeolite skeleton endowed Ni/Sm-AZ with superior catalytic stability and anti-sinter/anti-coke capabilities during 100 h of DRM reaction at 700 degrees C than NiSm/AZ. This is attributed to the enhanced metal-support interaction that can effectively stabilize the active metallic sites. CH4/ CO2-TPSR-MS coupled with in-situ DRIFTS techniques revealed that both the surface dispersion and skeleton incorporation of Sm could decline the CH4/CO2 activation temperature and facilitate the breaking of C-H and C=O bonds into more CHx* and O* species, thus achieving highly efficient and stable syngas production through the formation of CHxO* intermediates. The molecular level insights in the microstructure modulation of NiSm bimetallic catalysts reported in this work supplies an inspirational method for designing high-performance DRM catalysts.

Dry reforming of methane (DRM) is a green and highly efficient carbon valorization technology to simultaneously convert the two greenhouse gases (CH4 and CO2) into synthesis gas, but catalyst deactivation remains a persistent challenge for its industrialization. Herein, a series of NiFeCaAl-T (NFCA-T, T = 200, 400, 600) catalysts were synthesized using the co-precipitation method, and the synergistic roles of calcination temperature regulation, Fe species and Ca promoter in tuning the physico-chemical properties and DRM reaction behavior of assynthesized catalysts were investigated. Results showed the proper calcination temperature and Ca promoter contributed to the formation of stabilized Ni3Fe1 alloy with abundant oxygen vacancies, thereby the optimal NFCA-400 could maintain 77.5%/81.9% of CH4/CO2 conversion accompanied by only 2.3% and 3.1% decreases from initial values, respectively, after 100 h stability tests at 700 degrees C. Moreover, NFCA-400 demonstrated exceptional sinter resistance and coke tolerance, due to the improved metal dispersion and abundant CO2 activation centers of oxygen vacancies on the catalyst surface. Furthermore, based the CH4/CO2-TPSR-MS and insitu DRIFTS results, NFCA-400 was found following a HCOO*-intermediated pathway during DRM process. Alone, the OH* species derived from the formation/decomposition of HCOO* intermediates could collaborate with the O* species from CO2 dissociation to efficiently transform the carbonaceous intermediates (CHx*, C*) from CH4 dehydrogenation into syngas. This work offers a new perspective for constructing a stable NiFe bimetallic catalyst with superior anti-sinter/anti-coke ability for DRM.

The development of Fe-based catalysts with controllable iron carbide phases and product selectivity for Fischer-Tropsch to olefins (FTO) is a research hotspot and remains some challenges. Herein, the physical mixture of as-prepared zeolites (SAPO-18 and CoAPO-18) and iron carbide (K-FeCx) catalysts was directly used for FTO. The impact of zeolites on the phase transformations, reduction behaviors, H2 and CO adsorption, and FTO performance of K-FeCx has been investigated via a series of characterization techniques. The results demonstrated zeolites promoted the conversion of Fe7C3 (the dominant phases in fresh K-FeCx) into Fe5C2 and suppressed the agglomeration of active phases during FTO. Furthermore, the addition of zeolites significantly increased the CO conversion and served as catalytic cracking sites to reduce the carbon chain growth, resulting in the components of C5+ products concentrated in C5-C16. It also revealed that the acid strengths of zeolites altered the distributions of C2=-C4= and C5+ products. Among them, K-FeCx/CoAPO-18 exhibited 25.0% selectivity for C2=-C4= products, which was higher than that over K-FeCx/SAPO-18, while K-FeCx/SAPO-18 favored the production of C5=-C10 = products. Additionally, in situ FTIR revealed that physically mixed zeolites promoted the dissociation of HCOO-to CHX*, removal of O atoms and C-C coupling reactions.

Lignin valorization is crucial for obtaining sustainable fuels and chemicals, however its complex structure challenges efficient conversion. Herein, we designed a Ru-modified Co/attapulgite (CoRux/ATP) catalysts for achieving the catalytic depolymerization of lignin (CDL) under ethanol coupled with H2 medium to liquid fuel and guaiacols. CoRu1/ATP exhibited exceptional catalytic efficiency under optimal conditions, where the yields of liquid product and guaiacols reached 82.82% and 584.67 mg/g, respectively. Experiments with model compounds demonstrated that the addition of Ru could effectively reduce the activation energy of the (3-O-4 bond cleavage, which decreased from 78.6 kJ & sdot;mol- 1 to 73.5 kJ & sdot;mol- 1. Characterization results indicated that the Ru additive yielded Co-Ru interfaces and its hydrogen spillover effect promoted the reduction of Co3O4 to CoO and metallic Co (Co0) to produce more oxygen vacancies (VO). Additionally, the research on reaction mechanisms revealed VO and CoO phases in CoRu1/ATP enhanced the breakage of C-O bonds of lignin and the adjacent metallic Co and Ru sites and Co-Ru interfaces improved the activation of ethanol and molecular hydrogen into active hydrogen (H*) species to stabilize reactive intermediates and enhance hydrogenation reaction. The findings provide a potential method for directional lignin conversion.

Dry reforming of methane (DRM) offers a promising route for the valorization of two major greenhouse gases (CH4 and CO2), but its large-scale applications remain restricted by the development of high-performance catalysts. Herein, we report a CO2-treated Sm-modified Ni/MCM-41 catalyst (N1S/M-RCO2) exhibits high CH4 (78.13%) and CO2 (84.19%) conversions and superior resistance to sintering and carbon deposition. The catalytic behavior of the catalyst is close to the state-of-the-art in this field. Various characterization results reveal that Sm promoter coupled with CO2 treatment induced electronic interaction of nickel species with Sm additive to stabilize active components and yield cationic Niδ+ (0 < δ < 2) sites and suitable oxygen vacancies (VO), which efficiently improving the CH4/CO2 adsorption-activation and the resistances to sintering and carbon deposits. A combination of in situ DRIFTS spectra and DFT calculations uncovered that Niδ+ sites as the intrinsically active centers could significantly inhibit CH4 deep cracking (*CH → *C) and facilitate *CH oxidation (*CH + *O → *CHO). Additionally, the DRM mechanism over N1S/M-RCO2 has been clarified. In which, Niδ+ sites rapidly decomposed CH4 into *CHx (0 < x < 4) and simultaneously surface VO dissociated CO2 to generate *O, thereby boosting the formation of *CHxO intermediates to produce syngas. The designed dual tuning strategies for catalyst microstructure optimization have opened up an effective pathway for developing high-performance catalysts for DRM.

The valorization of crude glycerol from biodiesel production is essential for sustainable development. Aqueous phase reforming and in-situ hydrogenolysis of glycerol (ARHG) for producing green hydrogen and chemicals has emerged as a promising yet challenging strategy. Herein, we employed NaOH coupled with high-temperature treated attapulgite (A-OH) to prepare transition metals modified A-OH supported Pt catalysts (Pt-MOx/A-OH, M = Fe, Co, Ni or Cu) for ARHG. The introduction of transition metal oxides promoted the reduction of Pt and effectively mitigated the leaching of Pt. Amongst, Pt-FeOx/A-OH achieved the optimal hydrogen production rate of 795.87 mu mol/gcat/min at 240 degrees C during 1 h reaction. Upon extending the reaction time to 3 h, it exhibited the highest glycerol conversion (51.82 %) and the superior selectivity of 1,2-propanediol reached to 48.27 %. Characterizations revealed that, in Pt-FeOx/A-OH, the specific SiIV-O-Al(4) of A-OH could interact with Fe to form SiIV-O-Fe interfaces, effectively improving Pt species distribution. Additionally, the electron transfer from Fe to Pt led phase transformation from Fe3O4 to Fe2O3 and promoted the formation of electron-enriched Pts and increased lattice oxygen concentration (OL). Combination of in-situ DRIFTS spectrum and the distribution of gas/ liquid products, it demonstrated that the synergistic effect of Pts /Pt0 sites with OL facilitated the adsorption and activation of glycerol. Notably, the presence of Pts facilitated the desorption of hydrogen species (H*) to promote their recombination to form molecular hydrogen (H2). Additionally, the generated H* further reacted with acetol intermediates from glycerol dehydration to yield 1,2-PDO. Pts species accelerated H* species desorption to inhibit excessive hydrogenolysis of 1,2-PDO.

A series of Na-modified SiO2-supported Fe catalysts synthesized via different preparation methods including physical mixing, impregnation and precipitation, and applied into Fischer-Tropsch synthesis (FTS). Amongst, the Na-Fe/SiO2-p prepared by precipitation achieved the highest CO conversion (87.9

Although lignin is an abundant industrial by-product with intrinsic UV-blocking capabilities, its high-value valorization is severely hampered by its undesirable dark coloration and aggregation-induced quenching effects. Herein, this study presents a facile and eco-friendly biomacromolecule-assisted assembly strategy to upgrade lignin waste into visible-light transparent nanocomposites Z2L for advanced photoprotection. By leveraging the deprotonated phenolic sites of lignin as nucleation templates, molecular-level confinement of lignin chains within the Zeolitic Imidazolate Framework-8 was achieved. This spatial isolation effectively disrupts the extensive π-π stacking of lignin aggregates, simultaneously resolving the aesthetic bottleneck and amplifying UV absorption efficiency by 5.9-fold compared to pristine lignin. The engineered nanocomposites exhibit enhanced hydrophilicity, excellent thermal stability, and improved biocompatibility. Evaluations using murine models and porcine skin demonstrate that Z2L acts as a robust physical barrier effectively preventing UV-induced epidermal damage. Furthermore, the nanocomposites demonstrate integrated multifunctionalities, offering potent antioxidant activity and antibacterial defense against Staphylococcus aureus and Escherichia coli. This work presents a sustainable biorefinery paradigm for transforming industrial biomass waste into high-performance functional materials, offering a value-added alternative to synthetic UV filters.

In order to enhance the production of aromatic hydrocarbons, this study systematically investigated synergistic effects on pyrolysis behavior, kinetics, and product component distribution of co-pyrolysis of microalgae Chlorella pyrenoidosa (CP) and waste plastic polyethylene (PE) with and without HZSM-5 by thermogravimetric analysis (TGA) and pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). Reaction mechanism for the formation of aromatic hydrocarbons during the catalytic co-pyrolysis of CP and PE was elucidated. The thermal behavior indicates that the co-pyrolysis process of CP and PE can be distinctly divided into two stages, which mainly correspond to the pyrolysis of CP and PE, respectively. In comparison with co-pyrolysis of CP and PE, the catalytic co-pyrolysis can slightly reduce the first-stage CP pyrolysis, while significantly lowering the second-stage PE pyrolysis, which expands the overlap of the pyrolysis temperature ranges between CP and PE, thereby favoring the occurrence of synergistic effects, promoting devolatilization. The kinetic analysis results show that the activation energy values of the two thermal decomposition stages in catalytic co-pyrolysis are, respectively, lower than those of the corresponding stages in co-pyrolysis. Py-GC/MS results reveal that during the catalytic co-pyrolysis of CP and PE, the experimental values of oxygeneous and nitrogenated compounds are lower than the calculated values, while the experimental values of aromatic hydrocarbons are higher than the calculated values, which exhibit a significant synergistic effect between CP and PE, substantially promoting the production of aromatic hydrocarbons through the hydrocarbon pool mechanism and the Diels–Alder reaction, with the latter proposed to play a vital role in aromatic hydrocarbon formation.

In this work, attapulgite-based silicon (AS) with unique active silicon was employed to prepare La-modified ASsupported Ni-based catalysts for Dry reforming of methane (DRM). The effects of ultra-high temperature calcination (CT, 1000-1400 degrees C) and La content on catalyst structure and their DRM performance were in-depth studied. It was found that 15N1L/AS-1200 (1 wt.% La and 1200 degrees C CT) exhibited the highest conversions of CH4 (91%) and CO2 (89%) at 700 degrees C. Various characterizations demonstrated that 15N1L/AS-1200 increased the contents of surface active Ni0 sites, strong CO2 adsorption sites and lattice oxygen, which significantly enhanced the adsorption-activation of CH4/CO2 and the oxidization of carbonaceous species yielded during DRM. Consequently, 15N1L/AS-1200 achieved the negligible metal sintering and carbon deposits, and the DRM reaction mechanism over 15N1L/AS-1200 were revealed. This work is expected to supply expanding application of clay materials and a possible approach to develop high-performance catalysts for DRM.

Obtaining green hydrogen from glycerol steam reforming (GSR) is a promising approach for the efficient utilization of crude glycerol derived from the biodiesel market, while it faces significant challenges. Herein, Mo-modified attapulgite-based zeolite (AZc)-supported Ni-based catalysts (named as NixMo/AZc) were prepared for GSR. It demonstrated that AZc could reduce the proportion of strong acid sites and promote the reduction of nickel species; meanwhile, the Mo additive yielded an intermetallic interaction between nickel and molybdenum to facilitate the formation of Ni-Mo alloy phases and abundant oxygen vacancies (OV). These characteristics effectively inhibited the dehydration of glycerol, the sintering of active Ni metals, and the formation of carbon deposits during GSR process. Among them, Ni3Mo/AZc achieved the highest glycerol conversion (95.3%) and hydrogen yield (77.3%) and maintained the superior catalytic stability during 50 h of GSR at 600 degrees C. Additionally, the reaction pathway investigation exhibited that Ni3Mo/AZc promoted the dehydrogenation of glycerol and the acetol intermediate and the breakage of C-C bonds; then, its metallic Ni and Ni-Mo alloy sites coupled with OV enhanced the water-gas shift reaction and the steam reforming of various intermediates to yield more hydrogen. This study provides a feasible strategy for the high-value utilization of glycerol through steam reforming along with the efficient production of green hydrogen.

Iron - based Fischer - Tropsch synthesis (FTS) catalysts with a carbon - encapsulated core - shell structure have been a popular research focus on account of their remarkable performance and stability. Here, in order to explore the effect of K and/or N modification on the structure, evolution, and catalytic performance of Fe/Fe3C based catalysts, we synthesized a graphitic carbon-encapsulated Fe/Fe3C core-shell catalyst via direct pyrolysis of a ferric citrate and electron-donating reagent mixture. The effect of N doping and/or K promotion was studied using a combination of physicochemical methods. Results revealed that one-step pyrolysis and self-assembly of ferric citrate led to in situ redispersed formation of graphitic carbon-encapsulated iron oxides nanoparticles. In situ N doping facilitated reduction/carburization and formation of Fe/Fe3C, similar to K promotion, formed defective-rich surfaces that can enhance CO dissociative adsorption and promote Fe/Fe3C carburization evolution to Fe5C2. The synergy of N and K promoted higher Fe5C2/Fe3C active sites on the obtained K-Fe/NC catalysts, resulting in higher olefin/paraffin (O/P) ratios and chain growth capacity. Furthermore, there were no drastic changes in the catalyst morphology and performance during 120 h time on stream.

Fischer Tropsch synthesis provides a non-petroleum pathway for the production of high value liquid fuels and long-chain alpha olefins from syngas. However, regulating product distribution to promote the formation of high value product while maintaining low selectivity for C1 by-products (CH4 and CO2) remains a significant challenge. Iron based composite catalysts were prepared via dual doping and modification, i.e., alkali metals and transition metals using mesoporous silica SBA-15 as the support. The catalyst was characterized by XPS, XRD, H2-TPR, CO2-TPD, TEM, Roman and other methods, and the relationship between the catalyst structure and catalytic performance was studied. At 1 MPa and 300 °C, The CO conversion rate of Fe–Zn–K/SBA-15 (30

To investigate the deflagration characteristics of hydrogen-ammonia mixed gases, this study experimentally examines changes in flame propagating characteristics under different hydrogen blending ratios and equivalence ratios and conducts a detailed analysis of the combustion reaction mechanism using CHEMKIN software. The results reveal that flame morphology changes significantly with varying hydrogen blending ratios and equivalence ratios. At a hydrogen blending ratio of 0.2, only a single slope-type flame was observed. As the hydrogen blending ratio increases, the flame evolves into a flat and tulip-type flame, accompanied by oscillations at the flame front. Increasing the hydrogen blending ratio notably accelerates the flame propagation speed. In particular, increasing the hydrogen blending ratio significantly enhanced flame propagation speed, especially at blending ratios of 0.3 and 0.4. Initially, flame propagation speed increased steadily, but larger fluctuations emerged in the later stages. These fluctuations are likely associated with pressure wave reflections and morphological evolution of the flame front. When average flame propagation speed exceeded 1.4 m/s, tulip-shaped flames were observed, indicating a coupling between the complexity of flame propagation behavior and combustion reaction dynamics. Additionally, reactions R1: H + O2--O + OH and R9: H + O2(+M) = H2O (+M) have been identified as key elementary reactions controlling the deflagration process of the hydrogen-ammonia mixture. These reactions accelerate combustion by rapidly consuming H radicals and O2, thereby enhancing the deflagration characteristics. Therefore, this study provides important theoretical support and reference for the safe design and engineering applications of hydrogen-ammonia mixed fuel delivery systems, particularly in lean combustion conditions and pipeline environments, which are of great significance in promoting the safe development of zero-carbon emission fuels in the context of global carbon neutrality goals.

The direct oxidation of methane to methanol（DOMM） has been recognized as a significant technology for efficiently utilizing low-concentration coalbed methane（LCMM） and supplying liquid fuel.Herein,the noble metals（Pt,Pd and Ru） modified Cu/alkalized sepiolite（CuX/SEPA） catalysts were prepared and used for the DOMM in a gas-phase system at low temperatures.The CuRu/SEPA exhibited the highest methanol production of 53 μmol·g -1 ·h -1 and methanol selectivity of 90% under the optimal reaction conditions.Various characterizations demonstrated that the addition of Ru promoted the formation of Cu 2+ and the contraction of Cu—Si/Al bonds to reduce the distance between framework Al atoms of SEPA to further generate more Al pairs,which facilitated the formation of reactive dicopper species([Cu 2 O] 2+ or [Cu 2 O 2 ] 2+ ).Investigation of the reaction mechanism revealed that [Cu 2 O] 2+ or [Cu 2 O 2 ] 2+ species could adsorb and activate methane to form CH 3 O * species and ultimately generated methanol with the assistance of water.

Herein, alkali metals (Na, K, Mg and Ca) modified kaolin-supported Ni catalysts display bright prospect for ethanol steam reforming (ESR). It finds that alkali metals lower the proportion of acid sites, optimize the reduction of nickel species and create the interaction of nickel components with alkali metals. These features inhibit ethanol dehydration, Ni metal sintering and carbon deposits during ESR. Amongst, Ni-K/KL presents the highest ethanol conversion (97.5%) and H2 yield (76.3%) at 600 degrees C and almost no deactivation during 50 h of ESR. It demonstrates Ni-K/KL alters the reaction path by suppressing acetaldehyde intermediates in comparison with Ni/KL. Subsequently, the K-modified metallic Ni sites fleetly rupture intermediate C-C bonds and activate CO. Additionally, the Ni-O-K interface sites achieve H2O activation to produce abundant OH*. Eventually, the synergetic interplay of Ni0 with Ni-O-K improves the water-gas shift reaction and CHx steam reforming to produce more hydrogen.

Herein, a series of Fe-based biochar catalysts (xFe/WSBC) were synthesised via impregnation using wheat straw as a carbon precursor and applied to the Fischer-Tropsch synthesis of olefins (FTO) from syngas. Various characterisations of fresh catalysts demonstrated that Fe content significantly affected the dispersion of iron particles and the surface distribution of Fe3 +/Fe2+. Among the samples, 5Fe/WSBC exhibited the highest surface Fe3+/Fe2+ ratio and thus the lowest surface electron density, which enhanced the adsorption and activation of H2. In addition, an appropriate amount of the Fe additive (5 wt%) significantly decreased the Fe3O4 particle size, which promoted the continuous reduction and carbonisation processes during FTO to generate iron carbide phases, which boosted CO activation and the subsequent C-C coupling. Therefore, 5Fe/WSBC exhibited the highest CO conversion (46.9 %) and iron time yield (348.9 mu molCO & sdot;gFe- 1 & sdot;s- 1) as well as the major enhancement of selectivity to light olefins (C2=-C4=). The results for the used catalysts demonstrated that 5 wt% Fe clearly inhibited the sintering of iron particle size and improved the catalytic stability of FTO.

Catalytic depolymerization of lignin (CDL) is a prospective technology for the efficient utilization of biomass. In this paper, novel B-Ti-modified diatomite-supported nickel phosphide catalysts (xNiP/BTD) were prepared to depolymerize lignin in a unique formic acid-assisted aqueous-phase glycerol medium. Under optimal conditions, 4NiP/BTD exhibited 100% lignin conversion and 95.4% lignin oil (LO) yield, in which the yield of petroleum ether (PE)-soluble product reached 20.6%. Based on the characterization results, the superior performance of 4NiP/BTD for CDL was attributed to the collaborative effect of metallic Ni0 centers and acidic sites within Ni3P species. Among these, metallic Ni0 sites activated formic acid and aqueous-phase glycerol to generate active hydrogen (denoted as H*); subsequently, lignin was dominantly converted into phenol and alkyl guaiacol under the comprehensive function of H*, Lewis (Ni delta+ species), and Bronsted acid sites (P-OH groups). Additionally, a potential reaction pathway for CDL with 4NiP/BTD as the catalyst was suggested. This study established a feasible approach for the efficient conversion of lignin using crude glycerol and green clay resources.