Activation Energy Of Decomposition Research Articles

Effects of 2CL-20/HMX cocrystals on the thermal decomposition behavior and combustion properties of polyether solid propellants

Herein, the effects of cocrystals of two nitroamine explosives, namely hexanitrohexaazaisowurtzitane (CL-20) and 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane (HMX), which are denoted as CHC, on the combustion properties, heat release, and safety profiles of polyether solid propellants were systematically analyzed. The peak decomposition temperature of CHC was found to be 244.8 °C, which is lower than those of its component CL-20 and HMX. However, the thermal stability of CHC was similar to that of CL-20, and the thermal decomposition behavior of CHC was significantly different from that of a physical mixture of CL-20 and HMX. In addition, similar to CL-20, CHC was not completely decomposed upon heating, despite the decomposition activation energy of CHC (322.7 kJ·mol−1) being similar to that of HMX (322.4 kJ·mol−1). In contrast, the thermal decomposition behaviors of CHC-based propellants differed from those of solid propellants that were based on physical mixtures of CL-20 and HMX. During thermal decomposition, CHC did not decompose into CL-20 and HMX, and the heat released from the CHC-based propellants was more concentrated than that released from the other propellant mixture examined. Furthermore, the rate of combustion of CHC-based propellants fell between those of the CL-20- and HMX-based propellants at all the tested pressures. The pressure exponents of combustion rates of the examined CHC-based propellants were slightly lower than those of the CL-20- and HMX-based propellants, and the combustion rates and their corresponding pressure exponents decreased with a decrease in the CHC particle size. Moreover, the explosive heat of CHC-based propellant was between those of the CL-20-based and HMX-based propellants, and similar to that of a CL-20/HMX mixture-based propellant. Finally, the safety performance of CHC-based propellant was almost identical to that of the CL-20/HMX mixture.

Thermal Stability and Kinetics of Thermal Decomposition of Statistical Copolymers of N-Vinylpyrrolidone and Alkyl Methacrylates Synthesized via RAFT Polymerization

The thermal stability and the kinetics of thermal decomposition of statistical copolymers of N-vinylpyrrolidone (NVP) with the alkyl methacrylates, hexyl methacrylate (HMA) and stearyl methacrylate (SMA), were studied by Thermogravimetric Analysis (TGA) and Differential Thermogravimetry (DTG). Statistical copolymers of different compositions were studied, and their thermal decomposition behavior was compared to the corresponding homopolymers. The activation energies of the thermal decomposition were calculated using the Ozawa-Flynn-Wall, the Kissinger, and the Kissinger-Akahira-Sunose methodologies. The effects of the nature of the methacrylate monomer, the copolymer composition, and the rate of heating are discussed.

5‐(Chloromethyl)furfural production from glucose: A pioneer kinetic model development exploring the mechanism

AbstractConversion of glucose to 5‐(chloromethyl)furfural (CMF) is one of the well‐known high yield unit processes in lignocellulosic biomass valorization. A kinetic modeling study was not reported for the reaction, owing to the complexity in quantification of CMF. Herein we have successfully developed a rapid, sensitive, and specific HPLC method (reverse phase) to quantify the generated CMF (range: 10–650 μg/mL) in a dichloroethane solvent. The Box–Behnken design of experiment method employed for the statistical optimization. A kinetic model was developed based on the homogeneous first‐order kinetic model, and the results are in good agreement with the experiment data. The formation of CMF, 5‐(hydroxymethyl)furfural, formic acid, levulinic acid, and humins from glucose and HCl were modeled using a serial parallel reaction mechanism. The apparent activation energy (Ea) for glucose decomposition and CMF formation is 99 and 31 kJ/mol.

Evaluation of thermal hazards based on thermokinetic parameters of 2,4-dinitroanisole

ABSTRACT As a high-energy insensitive explosive which is expected to replace 2,4,6-trinitrotoluene (TNT), it is necessary to evaluate the thermal risk of 2,4-dinitroanisole (DNAN). In this article, the thermal performance of DNAN was tested using differential scanning calorimeter (DSC) and accelerating rate calorimeter (ARC). According to the test results, the decomposition activation energy (E), the pre-exponential constant (A), activation entropy (ΔS ≠), activation enthalpy (ΔH ≠), activation Gibbs free energy (ΔG ≠) at T P0 of the reaction and the critical temperature of thermal explosion (T b) were obtained. The kinetic model under adiabatic conditions was established. The thermal hazard assessment of DNAN was carried out according to the thermodynamic parameters, and the assessment results are of great significance to the application of DNAN.

Hydrogen storage properties of Mg-Li-Al composite system doped with Al2TiO5 catalyst for solid-state hydrogen storage

A systematic investigation was performed on the 4MgH2 + LiAlH4 destabilized system with the inclusion of 5 wt% Al2TiO5 that was prepared by a ball milling process, and the hydrogen sorption performances were studied for the first time. A great advancement of the onset dehydrogenation temperature and de/rehydrogenation kinetics of 4MgH2 + LiAlH4 composite was achieved by doping Al2TiO5 to the composite. For the first and second desorption stages, the 4MgH2 + LiAlH4 + 5 wt% Al2TiO5 composite began to liberate hydrogen at 85 °C and 230 °C. In comparison, the undoped system commenced to liberate hydrogen at 120 °C and 270 °C, which were 35 °C and 10 °C lower, respectively when contrasted with the undoped composite. For the rehydrogenation kinetics, about 1.9 wt% hydrogen was absorbed within 5 min for the 5 wt% Al2TiO5-doped 4MgH2 + LiAlH4 system, whereas the neat sample only absorbed about 1.2 wt% hydrogen under similar conditions. As for the dehydrogenation kinetics, 4MgH2 + LiAlH4 + 5 wt% Al2TiO5 composite desorbed 1.7 wt% hydrogen within 10 min of desorption, while the 4MgH2 + LiAlH4 system released 0.8 wt% hydrogen in the same time frame. The apparent activation energy for the MgH2-relevant decomposition decreased from 121 kJ/mol (4MgH2 + LiAlH4 system) to 102 kJ/mol, after 5 wt% Al2TiO5 was introduced into the destabilized system. The decline in particle size also enhance the hydrogen storage behaviors. The synergistic effect of Al2TiO5 on the hydrogen storage behavior of 4MgH2 + LiAlH4 sample is attributed to the formation of new species of TiH2, AlTi2 and LiTi2O4 after ball milling and heating process, which acted as a real catalyser in the 4MgH2 + LiAlH4 + 5 wt% Al2TiO5 destabilized system.

Strong yet tough, excellent thermal resistant and UV-Protective Polydopamine/Poly(vinyl alcohol) composites via hydrogen-bonding interaction

Strength and toughness are regarded to be mutually exclusive in polymeric materials. Herein, highly strong and tough polymeric materials, which simultaneously combined excellent heat resistance and UV-shielding function, were obtained by in-situ polymerization of dopamine in the presence of poly (vinyl alcohol) (PVA) solution based on hydrogen bonding interaction. Polydopamine (PDA)/PVA composites were prepared by a conventional solution-casting method. Strong hydrogen-bonding interaction between PDA and PVA was demonstrated by Fourier transform infrared (FT-IR) spectroscopy and rheological test. It is found that the addition of 2 wt% PDA has 42.6% and 104.9% increase in strength and toughness respectively compared with neat PVA. More importantly, the maximum thermal decomposition temperature of PDA-2 wt% composite was up to 389.0 °C with a remarkable increment of 79.4 °C. Accordingly, the decomposition activation energy of PDA-2 wt% composite was much larger than that of PVA. Additionally, unlike those fillers such as graphene and carbon nanotube, PDA-2 wt% composite was transparent in visible region but obviously blocked ultraviolet (UV) light. This work offers a simple and facile strategy to prepare strong, tough, thermal stable and UV-blocking polymeric materials, which will expand their applications in high-grade packaging and tissue engineering.

Synthesis and Properties of Hydrazine Picrate

Picric acid was reacted with liquid propellant anhydrous hydrazine to synthesize anhydrous hydrazine picrate. Its structure was characterized by elemental analysis, infrared spectrum analysis, nuclear magnetic resonance, and its thermal decomposition performance was analyzed by TG-DTG and DSC. The thermal decomposition of anhydrous hydrazine picrate was studied by using Kissinger method and its activation energy was calculated. The critical temperature of thermal explosion was calculated by using the characteristic data of non-isothermal DSC curve. The results shows that the thermal decomposition of anhydrous hydrazide is mainly between 179.8∼200.9°C, the decomposition process is exothermic reaction, the melting point is about 140°C, the non-isothermal kinetic equation is ln(β/T p 2 )=-17652 (1/T p)+28.009, the activation energy of thermal decomposition is E=146.76kJ/mol, pre-exponential factor lnA=30.34, and the critical temperature of thermal explosion T b=175.3°C. Anhydrous hydrazine picrate has the characteristics of simple synthesis, rapid reaction and good thermal stability. It provides a new way for the disposal and reuse of anhydrous hydrazine.

Processing End-of-Life Tube Lights for Recovery of Rare Earth Oxides

The investigation of secondary rare earth sources is attractive because of environmental concerns, economic benefits, and resource conservation. The present work investigates milling/mechanical activation, chemical and thermal (microwave) treatment for rare earth recovery from trichromatic phosphor of spent tubular lights. Ball milling prior to acid leaching of phosphor recovered 82% Y, 41% La, 33% Ce, 97% Eu, and 32% Tb. The activation energy for the thermal decomposition of the phosphor was determined as 498.9 kJ mol−1, 381.6 kJ mol−1, and 202.2 kJ mol−1 for Na2CO3, NaOH, and CaCl2, respectively. Mechanical activation with Na2CO3 reduced the decomposition temperature for microwave processing and yielded 99% Y, 97% La, 0.6% Ce, 99% Eu, and 80% Tb values. Direct leaching yielded 39 g Y-Eu oxide product; ball milling and the mechanical activation followed by acid leaching yielded 52 and 89 g of Y-Eu-La-Ce-Tb oxides, respectively, from the processing of 100 units of end-of-life tubular units.

Cu-MOF derived Cu/Cu2O/C nanocomposites for the efficient thermal decomposition of ammonium perchlorate

C-dispersed Cu/Cu2O/C nanocomposites were prepared using a simple one-step calcination of Cu-MOF. The morphology and the structure of the Cu/Cu2O/C nanocomposites were characterized using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The thermal decomposition catalytic effect of the obtained nanocomposites on ammonium perchlorate (AP) was investigated using the differential thermal analysis (DTA), and the catalytic mechanism was analyzed. The results showed that Cu-MOF increased the pyrolysis peak temperature of AP to 382.51 ​°C. Cu/Cu2O/C calcined at different temperatures had better catalytic effect on AP than Cu-MOF, and Cu/Cu2O/C-350 had the best catalytic effect on AP, decreasing the decomposition peak temperature and activation energy of AP by 87.55 ​°C and 86.51 ​kJ ​mol−1, respectively. Results showed that the prepared Cu/Cu2O/C-350 nanocomposites were a promising catalyst for AP.

Studies on the Effect of Ageing on Thermal, Ballistic and Mechanical Properties of Advanced Energetic Propellants

AbstractIn order to study the ageing behaviour of advanced energetic propellants during storage and the effect of nitrate ester on the shelf life, accelerated ageing tests were conducted on two types of propellants based on nitrate esters, BTTN (as P‐1) and NG:BTTN (1 : 1) mixture (as P‐2). Mechanical and ballistic characterization of P‐1 and P‐2 propellants were carried out during storage at ambient (27 °C) and elevated temperature (40 °C and 55 °C). During ageing, tensile strength and Young‘s modulus of propellants are increasing and percentage elongation is decreasing due to depletion of nitrate ester from the locus. Also, there is a loss of stabilizer with time during ageing. Thermal decompositions of P‐1 and P‐2 were studied using differential thermal analysis at four heating rates (1 °C/min, 2 °C/min, 5 °C/min, and 10 °C/min) during ambient and accelerated ageing. Activation energies for thermal decomposition were calculated using Kissinger's and Ozawa's methods by assuming first‐order reaction kinetics for first stage decomposition in DSC studies of aged propellants. The shelf life of propellants was predicted based on the classical Arrhenius equation using zero‐order kinetics of degradation of the propellant mechanical property i. e. percentage elongation. With the 30 percentage elongation as the critical evaluation parameter, predicted shelf life at 25 °C is 23.97 years and 12.17 years for P‐1 and P‐2 respectively.

Optical Study on PVA/PEG Blend Doped with Nano-Silica

Transparent films of polyvinyl alcohol/polyethylene glycol (PVA/PEG) blend loaded with different nano-silica (SiO2) content were prepared by using solution casting. The effect of SiO2 nanoparticle loading on the optical properties of selected PVA/PEG blend ratio is studied in the spectral region 200–700 nm. The present study monitors the changes in the optical dispersion parameters such as band tail width, extinction coefficient, refractive index, and optical dielectric constant calculated as a function of nano-silica content. The results revealed that the obtained optical parameters were strongly affected by the SiO2 content in the blend films. Also, Cauchy model is used to fit the wavelength dependence of the refractive index of the composites. In addition, thermogravimetric analysis indicates the increase of thermal stability of the composites with respect to pure blend. The Coats and Redfern model is used to calculate activation energies for decomposition.

Thermal Stability of Ionic Liquids: Current Status and Prospects for Future Development

Ionic liquids (ILs) are the safest solvent in various high-temperature applications due to their non-flammable properties. In order to obtain their thermal stability properties, thermogravimetric analysis (TGA) is extensively used to analyze the kinetics of the thermal decomposition process. This review summarizes the different kinetics analysis methods and finds the isoconversional methods are superior to the Arrhenius methods in calculating the activation energy, and two tools—the compensation effect and master plots—are suggested for the calculation of the pre-exponential factor. With both parameters, the maximum operating temperature (MOT) can be calculated to predict the thermal stability in long-term runnings. The collection of thermal stability data of ILs with divergent cations and anions shows the structure of cations such as alkyl side chains, functional groups, and alkyl substituents will affect the thermal stability, but their influence is less than that of anions. To develop ILs with superior thermal stability, dicationic ILs (DILs) are recommended, and typically, [C4(MIM)2][NTf2]2 has a decomposition temperature as high as 468.1 °C. For the convenience of application, thermal stability on the decomposition temperature and thermal decomposition activation energy of 130 ILs are summarized at the end of this manuscript.

The effect of rGO-Fe2O3 nanocomposites with spherical, hollow and fusiform microstructures on the thermal decomposition of TKX-50

rGO-Fe2O3 nanocomposites with spherical, hollow and fusiform Fe2O3 (s, h and f) microstructures have been successfully fabricated using DMF as solvent via a facile solvothermal method. The morphologies and compositions of the as-synthesized rGO-Fe2O3 (s, h and f) nanocomposites were systematically studied using SEM, TEM, XRD, FTIR, RAMAN and XPS analysis. The rGO-Fe2O3 (s, h and f) nanocomposites were used to catalyze the thermal decomposition of energetic TKX-50 and the corresponding kinetic parameters were calculated using an isoconversional model. The catalytic performance of Fe2O3 (s, h and f) during the thermal decomposition of TKX-50 was significantly improved after being anchored onto the surface of graphene oxide. The as-synthesized rGO-Fe2O3 (h) and rGO-Fe2O3 (s) nanocomposites have an excellent effect toward reducing the temperature and apparent activation energy (Ea) for TKX-50 decomposition, respectively. The excellent catalytic performance of rGO-Fe2O3 (h) nanocomposite can be attributed to its external and internal surfaces, which provide more active sites for TKX-50 decomposition. In addition, the interactions formed between rGO and Fe2O3 have a positive effect toward reducing the Ea.

Preparation and evaluation of structural, optical, dielectric and thermal characteristics of unirradiated and irradiated polyurethane/magnesium silicate composites

Polyurethane filled with various amounts (5, 10, 15, and 20 wt%) of magnesium silicate was fabricated by the solution casting method. The structural and physical properties of PU due to the influence of adding magnesium silicate together with gamma irradiation were investigated. The structural properties of the prepared composites were investigated via X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD analysis shows magnesium silicate formation in the PU matrix, which was further confirmed by the surface morphology images obtained by the SEM. Optical properties were characterized by ultraviolet–visible (UV–Vis) spectrophotometer. Refractive index dispersion was analyzed via the Wemple–Didomenico models. For both the unirradiated and irradiated composites, the ratio of carrier density to the effective mass, and the plasma frequency were calculated. Influences of magnesium silicate and gamma irradiation on these parameters as well as the dependence on the aforementioned additions were investigated. The dielectric investigation of the prepared composites reflected the increase of the dielectric constant, dielectric loss, and electrical conductivity with the addition of magnesium silicate and gamma irradiation, while it lowered with raising the applied frequency. The thermal stability of the prepared composites was investigated via thermogravimetric analysis. The thermal stability of all composites is significantly enhanced with the adding magnesium silicate and gamma irradiation. Kissinger model was applied to measure the activation energy of thermal decomposition and revealed the increasing trend of activation energy with the addition of the magnesium silicate and raising gamma absorbed dose. We believe that the outcomes of this work would provide a helpful contribution to the engineering of the components and the processes involved in the given structure presented.

Thermal decomposition behavior of thin Makino bamboo (Phyllostachys makinoi) slivers under nitrogen atmosphere

The present study investigated the effects of heat treatment on the thermal decomposition behavior (changes in the chemical composition and color, strain variation, and tensile properties) of a thin Makino bamboo (Phyllostachys makinoi) sliver. The performances, reactions, and formations in heat treated bamboo slivers were measured by thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). The results indicated that a high thermal stability, cross-linking of lignin condensation, hemicellulose deacetylation, and an increase in cellulose crystallinity were observed. In addition, the bamboo slivers after heat treatment had a higher Poisson’s ratio due to a decrease in the ductility in the loading direction and an increase in the transverse shrinkage. Furthermore, using isothermal dynamic mechanical analysis (DMA), the normalized storage modulus of the bamboo slivers rapidly decreased when the treatment temperature exceeded 220 °C. According to first-order thermal decomposition kinetics by Arrhenius activation theory, the activation energy for thermal decomposition of the bamboo slivers was calculated to be 142.2 kJ/mol.

Coaxial Ni-S@N-Doped Carbon Nanofibers Derived Hierarchical Electrodes for Efficient H2 Production via Urea Electrolysis.

Electrochemical water splitting into hydrogen is a promising strategy for hydrogen production powered by solar energy. However, the cell voltage of an electrolyzer is still too high for practical application, which is mainly limited by the sluggish oxygen evolution reaction process. To this end, hybrid water electrolyzers have drawn tremendous attention. Herein, coaxial Ni/Ni3S2@N-doped nanofibers are directly grown on nickel foam (NF), which is highly active for hydrogen evolution reaction. Meanwhile, the Ni3S2@N-doped nanofibers on NF prepared in an Ar atmosphere display superior urea oxidation reaction performance to previously reported catalysts. The cell voltage is about 1.50 V in urea electrolysis to deliver a current density of 20 mA cm-2, lower than that of a traditional water electrolyzer (1.82 V). The current density is around 77% relative to its initial value of 20 mA cm-2 after 20 h, superior to Pt/C|Ir/C-based urea electrolysis (14%). It is found that the synergistic effect between metallic Ni and Ni3S2, as well as the interfacial effect between metal centers and N-doped carbon, favors the initial dissociation of H2O and the adsorption/desorption of H* with thermal neutral Gibbs free energy. Meanwhile, the in-situ generated NiOOH on the outer surface of Ni3S2 possessed lower electrochemical activation energy for urea decomposition. Meanwhile, the abundant oxygen vacancies in electrodes could expose more active sites for the adsorption of intermediates, including H* and OOH*. It is also found that the hierarchical nanostructure of densely packed nanowires provides ideal electronic and ionic transport paths for fast electrocatalytic kinetics. The present work indicated that the modulation of compositions and hierarchical nanostructure is effective to prepare efficient catalysts for H2 production via urea electrolysis.

Custom pyrolyzer for the pyrolysis of chemical warfare agents

Thermal decomposition studies on a chemical warfare agent (CWA) simulant was performed using a custom built pyrolyzer. The goals of this study were to design, build and evaluate a simple pyrolyzer to meet the safety and security requirements necessary to obtain consistent CWA and CWA simulant pyrolysis data from multiple laboratories around the world. A custom made tubular flow reactor was built, the pyrolysis effluent was collected on solid sorbent tubes, and was analyzed by thermal desorption (TD) gas chromatography/mass spectrometry (GC/MS). Experiments were conducted with triethyl phosphate (TEP), a well-studied CWA simulant, to determine the activation energy (Ea) and rate constant (k) for the unimolecular decomposition of TEP under the designed experimental conditions and to validate pyrolyzer performance. Experiments with TEP were conducted at five different temperatures (375–440 °C) with samples collected at five flow rates. The activation energy for TEP decomposition was determined to be 32.0 ± 7.6 kcal/mol which is consistent with previous reported literature data.

Development of Wastewater Treatment Technique by Catalytic Oxidation in Superheated Steam

The purpose of this research was the development of a wastewater treatment technique using catalytic oxidation in superheated steam. The target substance was isopropyl alcohol (IPA). The experiment was carried out using a plug-flow reactor filled with MnO2 catalyst. The optimum decomposition condition was determined, and the kinetics of the catalytic oxidation reaction were analyzed. The experimental results were expressed as total organic carbon (TOC) removal. The dependences of the TOC removal on the reaction temperature and residence time were investigated. The TOC removal increased with the reaction temperature and residence time. It was 99.8% at 300°C, 0.9 MPa, 11 s, and oxidant ratio of 1.2. On the other hand, the TOC removal was constant for a long residence time at low reaction temperatures of 200 and 230°C. This was because acetone and acetic acid were produced via the oxidation of IPA, and they were detected as TOC. The reaction kinetics were examined using the pseudo-first-order reaction model; the TOC removal correlated well with this model. Based on the results of the kinetics, the activation energy (Ea) for TOC decomposition was determined from the Arrhenius equation; it was 56.1 kJ/mol. These results indicate that catalytic oxidation in superheated steam is useful for wastewater treatment.

Effect of adding different percentages of HfCl4 on the hydrogen storage properties of MgH2

Magnesium hydride (MgH2) is the best candidate material to store hydrogen in the solid-state form owing to its advantages such as good reversibility, high hydrogen storage capacity (7.6 wt%), low raw material cost and abundance in the earth. Nevertheless, slow desorption/absorption kinetics and high thermodynamic stability are two issues that have constrained the commercialization of MgH2 as a solid-state hydrogen storage material. So, to boost the desorption/absorption kinetics and to alter the thermodynamics of MgH2, hafnium tetrachloride (HfCl4) was used as a catalyst in this study. Different percentages of HfCl4 (5, 10, 15 and 20 wt%) were added to MgH2 and their catalytic influences on the hydrogen storage properties of MgH2 were investigated. Results showed that the 15 wt% HfCl4-doped MgH2 sample was the best composite to enhance the hydrogen storage performance of MgH2. The onset decomposition temperature of the 15 wt% HfCl4-doped MgH2 composite was decreased by ~75 °C compared to as-milled MgH2. Meanwhile, the desorption/absorption kinetic measurements showed an improvement compared to the undoped MgH2. From the Kissinger analysis, the apparent dehydrogenation activation energy was 167.0 kJ/mol for undoped MgH2 and 102.0 kJ/mol for 15 wt% HfCl4-doped MgH2. This shows that the HfCl4 addition reduced the activation energy of the hydrogen decomposition of MgH2. The desorption enthalpy change calculated by the van't Hoff equation showed that the addition of HfCl4 to MgH2 did not affect the thermodynamic properties. Scanning electron microscopy showed that the size of the MgH2 particles decreased and there was less agglomeration after the addition of HfCl4. It is believed that the decrease in the particle size and in-situ generated MgCl2 and Hf-containing species had synergistic catalytic effects on enhancing the hydrogen storage properties of the HfCl4-doped MgH2 composite.

Spent lithium-ion battery materials recycling for catalytic pyrolysis or gasification of biomass

This research work studied the pyrolysis characteristics of main biomass components (i.e. cellulose, lignin) in the presence of the spent Li-ion battery cathode (BC) enriched in transition-metals (e.g., Ni, Co). The BC with a good thermostability even at > 700 °C could be used as a catalyst for biomass conversion. The addition methods of BC to biomass such as one-step (directly mixing) and two-step (impregnation-drying) were comparatively studied. The two-step method had a better catalytic effect in biomass pyrolysis, contributing to the reduction of decomposition temperature and activation energy. Significantly, the two-step method had a strong catalytic effect in reducing the content of cellulose-derived sugars and increasing the content of ketones via dehydration and decarboxylation. In addition, the BC used by the two-step method had a high potential for biomass pyrolysis or gasification in promoting the catalytic cracking (i.e. H-transfer) of lignin-derived phenols (tar surrogates) to hydrocarbons and aliphatics (e.g., ketones).