Soot Oxidation Reaction Research Articles

Soot oxidation activity and stability of NMxCe1-xO2-y nanoparticles (NM = Pd, Rh, Ru) supported on functionalized alumina

NMxCe1-xO2-y (NM = Pd, Rh, Ru) nanoparticles deposited on functionalized alumina were studied as catalysts of soot oxidation reaction. The activity and stability of ceria nanoparticles increased with the dopant content and adequate method of the alumina functionalization. Using the support functionalized with a decane layer increased the nanoparticles' dispersion and improved the catalyst stability. After the first run of the reaction, some deactivation occurred in all doped systems, while in the subsequent runs, the catalysts were stable. The deactivation was caused by the shape and structure changes (decrease in the number of oxygen defects, exposure of less active (111) planes, and formation of large NMOx particles). The catalyst containing ceria particles doped with x = 0.05 ruthenium was the most active in all three soot oxidation runs with T50% = 448, 480, and 483 °C.

Effect analysis on passive and active regeneration performance of catalytic diesel particulate filters at the equilibrium point in the presence of ash layer

AbstractCatalytic diesel particulate filters (CDPF) form the main post‐processing devices for the diesel engines. Particulates trapped by CDPF can be oxidized by nitrogen dioxide (NO2) and oxygen (O2). The CDPF passive and active regeneration model on platinum‐based catalyst in the presence of ash layer, including the mass, momentum, and enthalpy balances of the gas and the solid phase, the gas diffusion, and the kinetic of the soot oxidation reaction is performed and validated by the bench test. The effects of different temperatures on CDPF passive and active regeneration at the equilibrium point are analyzed. Further, the effective analysis of ash loading and ash layer distribution on the equilibrium state is conducted. The research on CDPF passive and active regeneration at the equilibrium point in the presence of ash layer provides a theoretical basis for CDPF application.

Design strategies for MOFs-derived Ce10-xZrxOy catalysts with polyhedral coordination to enhance soot combustion

Various cerium-based metal–organic frameworks (Ce-MOFs and Ce10-xZrx-MOFs) and their derivatives (Ce10-xZrxOy complex oxide catalysts) with different structures and properties by modulating the organic ligands (i.e., trimesic acid (BTC), 1,2,4,5-benzenetetracarboxylic acid (PMA), and terephthalic acid (BDC)) and transition metal elements via the solvothermal method. The performance of these catalysts was tested in the diesel soot oxidation reaction. In contrast, morphology engineering and the introduction of heteroatom zirconium to modify CeO2 can significantly improve the catalytic activity and stability of the catalyst. Among them, the best Ce5Zr5Oy-BDC shows remarkable catalytic performance for soot oxidation, converting 90% of soot particles into CO2 at about 410 °C. A series of characterization results demonstrate that the engineering of morphology provides a highly active polycrystalline surface for the adhesion of reactants, and the electron transfer system caused by Zr doping weakens the Ce-O bond. With the help of their combined action, the exposed polycrystal surfaces greatly enhance the oxygen vacancy content and the ability to generate reactive oxygen species. The DFT investigations shows that the presence of Zr can weaken the Ce-O link, result in favorable defect structures, and the reactive oxygen species of formation were promoted. This study provides an idea for the design of non-precious metal catalysts with high activity and stability.

Effects of ammonia addition on the soot nanostructure and oxidation reactivity in n-heptane/toluene diffusion flames

Co-firing NH3 with conventional hydrocarbon fuels is an important approach for reducing CO2 emissions in existing combustion systems. Besides CO2, the blending of NH3 would also notably affect soot formation and its oxidation behaviors. In the present study, we focus on the effects of NH3 on the nanostructure and oxidation characteristics of soot produced in diffusion flames of n-heptane/toluene mixtures. Two configurations of laminar co-flow diffusion flame, including both normal and inverse diffusion flames (NDF and IDFs), were used for investigation. High-resolution transmission electron microscopy (HRTEM), Raman spectroscopy (Raman), and Thermogravimetric analysis (TGA) were employed for soot characterization. The HRTEM and Raman spectra showed that with the increase of NH3 blending ratio, the fringe length (La) and the degree of graphitization decreased while the microcrystal tortuosity (Tf) increased. The results are in consistent with TGA analysis which suggests the promoting effects of NH3 on the soot oxidation reactivity. Difference between NDF and IDF with respect to the soot nanostructure and oxidation activity were discussed. It is our hope that the present results could deepen our understanding on the effects of NH3 on soot nanostructure and oxidation behavior and benefit the design of particulate filters for combustion devices fueled with hydrocarbon/NH3 mixtures.

Modification of SmMn2O5 Catalyst with Silver for Soot Oxidation: Ag Loading and Metal–Support Interactions

A series of Ag-modified manganese-mullite (SmMn2O5) catalysts with different Ag contents (1, 3, and 6 wt.%) were prepared via a citric acid sol–gel method for catalytic soot oxidation. The catalysts were characterized by powder X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Raman spectroscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy analysis (HRTEM), X-ray photoelectron spectroscopy (XPS), and H2 temperature-programmed reduction (H2-TPR). The soot oxidation activity of the mullite was significantly promoted by the addition of silver and affected by the loading amount of the metal. Herein, the influences of silver loading on the metal size distribution and its interactions with the mullite were studied. Based on these characterizations, a possible soot oxidation reaction mechanism was proposed for silver-modified SmMn2O5.

Study on the morphology, nanostructure and fragmentation properties of diesel and diesel-DMM soot particles oxidized in the air/air-NO environment

As an alternative fuel for diesel engines, dimethoxymethane (DMM) has attracted wide attention in recent years, but its impact on the post-treatment process of diesel exhaust particles has been rarely studied. To get a better understanding of the oxidation kinetics of soot in diesel particulate filters (DPFs), the oxidation process of soot emitted from a modern compression ignition (CI) fueled by diesel (D100) and its blend with 11 vol% dimethoxymethane (DMM11) at the same working conditions were investigated by a thermogravimetric analyzer in the air and air-NO atmospheres in this study, respectively. Soot samples at different oxidation degrees (0 %, 20 %, 50 % and 80 % mass loss) were tested by a high-resolution transmission microscopy to characterize the variations of physical properties (morphology, fractal dimension, primary particle diameter and nanostructure) and oxidation-induced fragmentation properties over the oxidation process. The results showed that DMM11 soot had higher oxidation reactivity than D100 soot, and the oxidation reactivity of soot was enhanced by NO involved in the air atmosphere. During the oxidation process, the fractal dimension of D100 and DMM11 soot aggregates gradually increased, and the number and diameter of the primary particles in an aggregate became smaller. This variation trends became more obvious with the presence of NO in the air environment. The nanostructures of D100 and DMM11 soot particles gradually become ordered (characterized by longer fringe length, narrower separation distance and less tortuosity) as the oxidation proceeds. While, when NO added in the air atmosphere the possibility of microcrystals oxidation inside the particles decrease to slow down the getting-ordered rate of soot. Moreover, the fragmentation probability of D100 and DMM11 soot aggregates decreases gradually as oxidation proceeds. During the oxidation process, the probability of primary particle fragmentation for D100 soot increases continuously, while the probability of DMM11 primary soot particles fragmentation showed an increase-then-decrease trend. Compare with D100 soot, DMM11 soot are more likely to occur the fragmentation behavior over the oxidation process. It is worth noting that the addition of NO to the air atmosphere increases the possibility of aggregate fragmentation, while it decreases the possibility of primary particle fragmentation. This work can provide theoretical basis for the development of high efficiency purification technology for diesel exhaust particles.

Investigation of the nanostructure and reactivity of soot particulates from diesel/methanol dual-fuel combustion with and without EGR

Independently of the methanol substitutions, introducing EGR for diesel/methanol dual-fuel combustion lowers soot oxidation reactivity and this trend is highly linked with the more ordered nanostructure.

Low temperature oxidation of diesel soot particles over one-dimensional 2 × 3 tunnel-structured Na2Mn5O10 catalysts

Tunnel-structured manganese oxides have drawn widespread research attention due to their excellent oxidation properties for the soot oxidation reaction. In this study, a series of romanechite Na2Mn5O10 catalysts with a 2 × 3 tunnel structure were synthesized via a facile hydrothermal method. The as-synthesized catalysts were investigated using X-ray diffraction, scanning and transmission electron microscopy, H2 and soot temperature-programmed reduction, O2 temperature-programmed desorption, NO temperature-programmed oxidation, X-ray photoelectron spectroscopy, and other measurements. Among all the catalysts, the Na1MnyOδ-120 catalyst exhibited the best catalytic performance for soot combustion, with T10, T50, and T90 values of 281 ℃, 317 ℃, and 343 ℃, respectively, which were considerably reduced to 271 ℃, 310 ℃, and 335 ℃ in the existence of 10% H2O. The results of multiple characterization methods indicated that the Na2Mn5O10 catalysts exhibit good reducibility, strong oxygen adsorption and activation capacity, and NO to NO2 oxidation ability. Moreover, the active sites (Mn and oxygen vacancies) and reaction mechanism (Langmuir–Hinshelwood) were also revealed by in-situ DRIFT and density functional theory calculations results. This study details a new strategy for the design and synthesis of efficient soot oxidation catalysts with practical application prospects.

Evolution of physicochemical characteristics of soot in a single coal combustion flame

This study experimentally investigated the evolution of the nanomorphology, graphite crystals, oxidation reactivity, and functional groups of soot in a single coal combustion flame. Nascent (sample #1), young (sample #2), and mature (sample #3) soot were collected from a Shenhua single coal combustion flame. The soot samples were then tested and analyzed using high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy to determine their physicochemical characteristics. The results showed that the nascent soot was an individual particle, the mature soot was a highly agglomerated soot aggregate, and the young soot was a transitional particle. The primary particles of sample #1 comprised several randomly orientated individual polycyclic aromatic hydrocarbon (PAH) crystal sheets, whereas the primary particles of samples #2 and #3 were typical core-shell graphite structures. The sp2/sp3 content, volatile organic fraction, and oxidation rate constant of samples #1, #2, and #3 decreased, resulting in successively weakened reactivity. The infrared spectrum absorption of 2800–3000 and 1700–900 cm−1 indicated that the hydrogen in the three coal-derived soot samples was mainly aromatic rather than aliphatic. Furthermore, the proportion of solo and duo aromatic out-of-plane (OPLA) CH bending in samples #1, #2, and #3 increased, whereas the proportion of trio-quatro OPLA CH bending decreased.

Incorporating of TiO2 with oxygenated fuel and post-injection strategy in CRDI diesel engine equipped with EGR: A step towards lower NOX, PM and enhance soot oxidation reactivity

A mixture of diesel, biodiesel (from algae), and butanol was mixed with nano-titanium dioxide at 50 and 100 parts per million in this study under post-injection (PI) strategy and two rates (10 % and 20 %) of exhaust gas recirculation (EGR). In the literature, few studies have investigated how PI strategies effect on engine emissions and combustion performance from mixture of B16M20 by butanol (16 %), microalgae biodiesel (15 %) and diesel with variable EGR rates. To gain a better understanding of the effects of EGR rates on diesel engines running with B16M20 mixture, this study was conducted. The final fuel type test used B16M20 treated with 50 ppm and 100 ppm of nano-TiO2. Fuel specific fuel consumption (BSFC) increased by 3 % for both diesel and B16M20 when EGR was used, but PI reversed this trend. Nanoparticles added to B16M20 blend significantly contributing in decreased BSFC to 6.47 %. 100 ppm nano-TiO2 added to 10 % of EGR, along with PI, can achieve the same or enhance better brake thermal efficiency (BTE) by 4.53 % than pure diesel. The lowest NOX levels by 26.48 % were achieved with 100 ppm nano-TO2 and B16M20 with 20 % EGR. Because of EGR's high heat capacity and dilution effect, higher EGR rates result in higher soot levels. As a result of the PI strategy, the soot levels emitted from B16M20 reduced by 28.57 % compared with diesel fuel. At PI strategy presence (W PI) and adding 100 ppm nano-TiO2 into the B16M20 blend resulted in the lowest PM concentrations by 59 % compared to the diesel and without PI (W/O PI). PM emissions were significantly reduced at temperatures below 600 °C from B16M20 blend combustion with delay injection, 10 % EGR, and 100 ppm nano-TiO2. Soot oxidation was minimized through EGR, and enhanced by nano-TiO2. Adding this 100 ppm of nanoparticles to diesel fuel produced more reactive soot than diesel fuel alone.

H2/NH3 Addition Effects on Flame Characteristics and Soot Formation in Ethylene Inverse Diffusion Flame

Zero-carbon alternative fuels such as hydrogen and ammonia are gaining popularity. Blending these fuels with hydrocarbons is an intermediate approach to mitigate soot and carbon dioxide production. Recent studies have concentrated their attention to the effects of ammonia and hydrogen on the soot production of hydrocarbon fuels. It is still necessary to completely comprehend how this influence is dependent on the type of fuel and flame configuration. In this work, the effect of hydrogen and ammonia addition on soot production in ethylene laminar inverse diffusion flames (IDF) was numerically examined for the first time. The thermal, chemical, and combined effects of hydrogen and ammonia were assessed by fictitious species. The experimental results from the literature were used to validate the temperature and soot volume fraction profiles. Results indicated that the flame temperature and the production of radicals are promoted chemically by hydrogen addition but inhibited under the thermal effect of ammonia. The principal source of the reduction in OH-represented flame height, soot volume fraction, average diameter, and primary particle number density in the IDF is the thermal effect of additives, and hydrogen addition performs better than ammonia. The major and intermediate species, the aromatic hydrocarbons, and the soot formation or oxidation reaction rates are decreased mainly by the hydrogen and ammonia thermal effect while increased moderately by the chemical effect. Therein, the reduction in soot generation is mainly due to the polycyclic aromatic hydrocarbon condensation rate being slowed down by additives. The inhibition is attributed to the thermal effect of additions, and hydrogen behaves better than ammonia.

Pivotal role of MnOx physicochemical structure in soot oxidation activity

Arising an interest in climate and health problems, catalytic soot oxidation and its mechanism need to be understood, in order to effectively reduce PM (particulate matter) emissions from industry and transportation. Here, a synergistic effect of the Mn physicochemical structure on the soot oxidation activity of Ti-based oxide catalysts is investigated. To unravel the structural change and role of different Mn species, a comparison of different Mn loading and pretreatment conditions was done. While a fine loading with different Mn arrangements is observed by XRD analysis, a comparative XPS study of these Mn catalysts reveals the predominant presence of Mn3+ oxidation state and optimal combination of surface adsorbed and lattice oxygen species (ratio of 1.07) imparts a promotional role in soot oxidation activity. Furthermore, the TPR, O2-TPD, and TEM analysis represent that the increased Mn amount with different configurations led to a decreased reducibility, difficulty in lattice oxygen accessibility, and changed the morphology of MnOx species from cubic to hexapod and/or truncated octahedra associated with the presence of α-Mn2O3-C, β-MnO2 and/or α-Mn2O3-TO, respectively. The presence of smaller segregated cubic particles, ease of reducibility, and predominant presence of Mn3+ species led to superior performance even at lower 10 %Mn supported TiO2 catalyst and was revealed with an activation energy of 112.9 kJ mol−1. This proves the consequence of a proper design of an optimum Mn structure on oxide supports for an efficient soot oxidation reaction.

Formation and Evolution of Soot in Ethylene Inverse Diffusion Flames in Ozone Atmosphere.

Ozone is a prospective additive for enhancing and controlling combustion under lean or very lean conditions, and reduces NOx and particulate matter emissions simultaneously. Typically, in studying the effects of ozone on combustion pollutants, the focus is on the final yield of pollutants, while its detailed effects on the soot formation process remain unknown. Here, the formation and evolution profiles of soot containing morphology and nanostructures in ethylene inverse diffusion flames with different ozone concentration additions were experimentally studied. The surface chemistry and oxidation reactivity of soot particles were also compared. The soot samples were collected by a combination of the thermophoretic sampling method and deposition sampling method. High-resolution transmission electron microscopy analysis, X-ray photoelectron spectroscopy and thermogravimetric analysis were applied to obtain the soot characteristics. The results showed that soot particles experienced inception, surface growth, and agglomeration in the ethylene inverse diffusion flame within a flame axial direction. The soot formation and agglomeration were slightly advanced since the ozone decomposition contributed to promoting the production of free radicals and active substances in the ozone added flames. The diameter of primary particles in the flame with ozone addition was larger. With the increase of ozone concentration, the content of soot surface oxygen increased and the ratio of sp2/sp3 decreased. Furthermore, the addition of ozone increased the volatile content of soot particles and improved soot oxidation reactivity.

Soot formation in asymmetrical ethylene jet flame-wall interactions

Soot from asymmetrical flame-wall interactions in inclined ethylene jet diffusion impinging flames was studied. The soot morphology, nanostructure and oxidation reactivity were acquired via transmission electron spectroscopy, high resolution transmission electron spectroscopy and thermogravimetric analyzer. Effects of oblique burner angles (θ), Reynolds numbers (Re) and nozzle to plate distances (H) on soot formation and evolution were analyzed. The results showed soot from downhill position presented the higher crystallization degree and the lower oxidation reactivity than soot from uphill position due to the asymmetrical FWI. With θ increased, the promoting effect of the plate on combustion was enhanced at the downhill side and was impaired at the uphill side. The oxidation reactivity of soot with lower crystallization degree from uphill position was improved, while the opposite variation trend was observed from downhill position. Soot from both uphill and downhill positions has the higher carbonization degree and the lower reactivity when Re increased. Soot particles had the shorter fringe length and larger fringe tortuosity and presented the higher reactivity with the augment of H. The reduction of the velocity perpendicular to the wall with the extension of free jet region suppressed soot formation and evolution at uphill and downhill sides.

Synthesis and catalytic properties of praseodymium oxide (Pr6O11) nanorods for diesel soot oxidation

In this study, a series of praseodymium oxides (Pr6O11) was developed by CTAB-assisted coprecipitation method. The praseodymium oxides were deeply characterized by XRD, N2 adsorption, SEM, HR-TEM, H2-TPR, soot-TPR, NO-TPO and in situ DRIFTS, and tested for soot combustion in absence/presence of NO atmospheres under tight/loose contact conditions. As a non-noble metal and single element oxide, the Pr6O11 catalysts exhibited excellent catalytic performances for both soot oxidation (T10 = 341 ℃, T50 = 395 ℃) in O2 and NOx adsorption (NAC, 906 μmol/g) at low temperature. It was believed that the relatively large surface area, strong NO oxidation ability and high intrinsic activity contributed to the superior performances. A promoting effect on soot oxidation was found when NO introduced, which was ascribed to the NOx-assisted mechanism. The in situ DRIFTS was used to explore the possible mechanism in the soot oxidation reaction process. The carboxyl was detected over Pr6O11 and was speculated as carbon-oxygen intermediate in soot oxidation.

Advances in soot particles from gasoline direct injection engines: A focus on physical and chemical characterisation

With an increasing market share of gasoline direct injection (GDI) vehicles, high particulate emissions of GDI engines are of increasing concern due to their adverse impacts on both human health and the ecological environment. A thorough understanding of GDI nanoparticulate properties is required to develop advanced particulate filters and assess the exhaust toxicity and environmental impacts. To this end, this paper aims to provide a comprehensive review of the physical and chemical characteristics of GDI nanoparticles from a distinctive perspective, including soot oxidation reactivity, morphology, nanostructure, surface chemistry, chemical components, and their correlations. This review begins with a brief description of nanoparticle characterisation methods. Then, the nanoparticle characteristics of GDI engines are reviewed with the following aspects: in-cylinder soot, exhaust particulate features, and a comparison between GDI and diesel nanoparticles. Previous studies showed that exhaust nanoparticle presents a more stable nanostructure and is less prone to oxidation if compared with in-cylinder soot. Additionally, GDI particles are less-ordered, more inorganic and metallic containing, and more reactive than diesel particles. Afterwards, the impacts of engine operating parameters and aftertreatments on GDI soot features are discussed in detail. Finally, the conclusions and future research recommendations are presented.

Relevance of soot formation characteristics to equivalence ratio and CO2 addition of acetylene flame

Soot is a common byproduct of fuel combustion that not only blocks machine operation but damages the environment and human health. A premixed acetylene flame was used to investigate the effects of equivalence ratio (2.30–2.66) and CO 2 addition (10% ∼ 50%) on soot formation characteristics evaluated by TG, SEM, TEM, Raman, FT-IR, and XPS. In the flame at φ = 2.47, the produced soot exhibits a higher activation energy with a larger particle size, less disordered structure, lower level of aliphatic carbon and higher degree of graphitization. The addition of 25% CO 2 results in the formation of soot with low activation energy, large particles, more disordered carbons, low sp 2 /sp 3 ratio and low surface oxygen content. Furthermore, it is found that the soot oxidation reactivity is correlated to the disorder structure, graphitized degree and oxygen-containing groups. Rate of production (ROP) analysis was conducted by kinetic simulation to better understand the characteristics of acetylene soot formation. • Characteristics of acetylene soot at various equivalent ratios and CO 2 are studied. • Natures of soot show volcano curves with flame equivalence ratio and CO 2 addition. • Soot reactivity is related to disorder carbon, graphitization and oxygen content. • Effects of equivalent ratio and CO 2 on rate of production of benzene are exhibited.

Soot characteristics from diffusion flames coupled with plasma

The study of soot characteristics in plasma-flame interaction was necessary to improve combustion efficiency and reduce pollutant emissions. This work experimentally investigated effects of plasma on soot formation, evolution and characteristics in ethylene diffusion flames by both optical diagnostic and sampling methods. The optical diagnostic method was employed to capture the two-dimensional distribution of soot temperatures and concentrations. Moreover, the nanostructure, crystallite properties and oxidation reactivity of soot from diffusion flames with plasma addition were obtained using transmission electron microscopy, Raman spectroscopy, thermogravimetric analysis and X-ray diffraction spectroscopy. The flame shapes and luminosity varied depending on the electrical parameters and oxygen concentration. It was found that the overall temperature increased somewhat with plasma activation, but remained roughly constant when the discharge frequency or applied voltage increased. The soot concentration immediately reduced with plasma on and then displayed different trends as the discharge frequency or applied voltage increased. The variation in soot concentration was caused by the combination of several parameters, including flame behavior, soot temperature and the effect of the electric field by energetic and chemically active species. The generated soot showed typical chain-like aggregates without plasma, but more film-like materials were presented with plasma acting on flames. The soot graphitization degree decreased notably with plasma generation resulting in higher oxidation reactivity because the shorter residence time and the plasma activation were simultaneously obtained, which both illustrated an inhibition effect of plasma on soot emissions. The disordered carbon content related to soot oxidation reactivity.

Impact of PODE3 on soot oxidation reactivity at different stages in n-heptane/toluene diffusion flames

PODE3, with the molecular formula of CH3O(CH2O)3CH3, is considered a highly competitive alternative fuel due to the absence of CC bond and its high oxygen content, and have been shown to significantly reduce soot emission when applied as a diesel fuel additive. However, the effect of PODE3 addition on the oxidation reactivity of soot generated in the flame remains unclear which is of great importance for the optimal design of the post-treatment devices during its application. In this work, the impact of PODE3 (0 %, 10 %, and 20 % by volumetric fraction) addition on the oxidation reactivity of soot at different maturity and oxidation degrees in n-heptane/toluene co-flow diffusion flames was specially investigated combining information on thermogravimetric analysis, high-resolution transmission electron microscope, and Raman spectroscopy. Results showed that PODE3 substitution significantly shrank soot generation region, and increased the flame temperatures before height above burner (HAB) < 45 mm. The addition of PODE3 improved the soot oxidation reactivity, which had a strong ability to hinder the growth of the microcrystalline carbon layers and resulted in a high content of amorphous carbon in soot particles. Specifically, it had more significant impacts on the soot in the oxidation stage than the surface growth stage. These can be explained that with PODE3 addition, on the one hand, the “reliable carbon atom” for soot formation is significantly reduced and the amount of oxidizing species is increased, resulting in a smaller particle size and a higher content of disordered and amorphous carbon in soot particles. On the other hand, the flame temperatures increased where HAB < 45 mm, which would promote the soot formation reactions. The combined effects of these factors make PODE3 have more significant inhibitory impacts in reactivity of soot sampled at oxidation stage than that at surface growth stage. Therefore, the impact of PODE3 addition on soot nanostructures and oxidation reactivity is not only reflected in its chemical effect but also in temperature effect.

Diesel/methanol dual-fuel combustion: An assessment of soot nanostructure and oxidation reactivity

The use of renewable methanol partly substituting diesel fuel can support the transition to low-carbon engines, in the form of diesel/methanol dual-fuel combustion. Particulate filters are still required for diesel/methanol dual-fuel combustion engines to meet the emission standard. Their periodical regeneration depends on the soot oxidation reactivity and nanostructure. We therefore assessed the influences of premixing methanol on soot oxidation reactivity and nanostructure at both engine loads. The results showed that increasing methanol substitution ratio shifted thermogravimetric profiles towards low temperature direction. The average activation energies of M20 and M40 samples (the methanol substitutions of 20% and 40%) dropped by 41.1–43.9 kJ/mol and 53.2–99.7 kJ/mol compared to diesel one at both engine loads, respectively. With an increase in methanol substitution ratio, a notable reduction in primary particle size was observed, with the shorter and more tortuous fringes as well as larger separation distance between the stacked fringes. The increasing trend in soot oxidation reactivity with methanol addition correlated well with the changes in primary particle size and fringe parameters, which means that soot oxidation reactivity highly depends on its morphology and nanostructure. It can be expected from the results that diesel/methanol dual-fuel operation has the advantages in engine fuel economy improvement regarding the regeneration of particulate filters.