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Aiming to elucidate the hydrogen absorption/desorption cycling properties of Mg-based alloys with in-situ formed Mg2Ni and LaHx (x = 2, 3) nanocrystallines, the hydrogen storage cycle stability, hydriding/dehydriding cycling kinetics and thermodynamic stability of the experimental alloys have been investigated in detail. The results show that the Mg–Ni–La alloys exhibit improved hydrogen storage cycling properties and can remain storage hydrogen above 5.5 wt% after 200 cycles. With the increase of cycling numbers, the dehydrogenation rates of the experimental samples increase firstly and then gradually decrease, and eventually maintain relative stable state. Microstructure observation reveals that powders sintering and hydrogen decrepitation both exist during hydrogen absorption/desorption cycles due to repeated volume expansion and contraction. Meanwhile, the in-situ formed LaHx (x = 2, 3) and Mg2Ni nanocrystallines stabilize the microstructures of the particles and hinder the powders sintering. After 200 cycles, the average particle size of the experimental samples decreases and the specific surface area apparently increases, which leads to the decomposition temperatures of MgH2 and Mg2NiH4 slightly shift to lower temperatures. Moreover, Mg2Ni and LaHx (x = 2, 3) have been proven to be stable catalysts during long-term cycling, which can still uniformly distribute within the powders after 200 cycles.

A new NLO crystal of L-Arginine doped with potassium iodide were harvested from solution growth technique with slow evaporation method. Powder X-ray diffraction analysis exposes the structure. Presence of vibration functional groups in the grown crystal was confirmed by FTIR spectroscopy. Using the spectrum of UV–Vis-NIR the optical transmission and absorption spectra were studied. TGA-DSC studies reveal the decomposition and thermal stabilities of the grown crystals. Kurtz Perry Powder technique determines the second harmonic generation NLO behavior.

No consensus has been reached on the role of reducible and irreducible supports on the reaction pathway of CO oxidation over supported metal catalysts. Here, colloidal ligand-free Pt nanoparticles were deposited on Al2O3 and CeO2 to investigate the support effect in CO oxidation by in situ diffuse reflectance Fourier-transform infrared spectroscopy (DRIFTS) and mass spectrometry (MS). On Pt/Al2O3, the carbonate-like intermediates accumulate and do not decompose to CO2 at the ignition temperature (150 °C) or above; the conversion of CO to CO2 follows classic Langmuir−Hinshelwood (L–H) mechanism with direct reaction of CO and O2 on Pt. Whereas for Pt/CeO2, the CO conversion to bidentate carbonate (b-CO32−) species followed by decomposition to CO2 is a main reaction pathway leading to its high reactivity at low temperature (75 °C). CeO2 facilitates the activation of oxygen to produce the carbonate-like intermediates and further decomposition to CO2, which resulted in a lower ignition temperature.

The cognition of active sites in the Ni-based catalysts plays a vital role and remains a huge challenge in improving catalytic performance of low temperature CO2 dry reforming of methane (LTDRM). In this work, typical catalysts of SiO2 and γ-Al2O3 supported Ni and Ni-Ce were designed and prepared. Importantly, the difference in the chemical speciations of active sites on the Ni-based catalysts is revealed by advanced characterizations and further estimates respective catalytic performance for LTDRM. Results show that larger [ Ni n 0 ] particles mixed with [Ni-O-Sin]) species on the Ni/SiO2(R) make CH4 excessive decomposition, leading to poor activity and stability. Once the Ce species is doped, however, superior activity (59.0% CH4 and 59.8% CO2 conversions), stability and high H2/CO ratio (0.96) at 600 °C can be achieved on the Ni-Ce/SiO2(R), in comparison with other catalysts and even reported studies. The improved performance can be ascribed to the formation of integral ( [ Ni n 0 ] -[CeIII-□-CeIII]) species on the Ni-Ce/SiO2(R) catalyst, containing highly dispersed [ Ni n 0 ] particles and rich oxygen vacancies, which can synergistically establish a new stable balance between gasification of carbon species and CO2 dissociation. With respect to Ni-Ce/γ-Al2O3(R), the Ni and Ce precursors are easily captured by extra-framework Aln-OH groups and further form stable isolated ( [ Ni n 0 ] -[Ni-O-Aln]) and [CeIII-O-Aln] species. In such a case, both of them preferentially accelerate CO2 adsorption and dissociation, causing more carbon deposition due to the disproportionation of superfluous CO product. This deep distinguishment of chemical speciations of active sites can guide us to further develop new efficient Ni-based catalysts for LTDRM in the future.

The phosphorus-doped carbon materials as one of novel carbon catalysts towards the hydrogen evolution reaction (HER) have attracted considerable attention over the past years. However, the role of C-P species palyed in the HER activity is still not clear up to now. Phosphorus-doped carbon nanotubes (P-CNTs) were prepared by chemical vapor deposition and annealed at 900, 1000 and 1200 ℃ to remove all or parts of phosporus species, resulting in four samples with different proportions of graphite-, pyridine- and pyrrole-like P species. The correlations between their HER activity and the contents of three types of P species were investigated. Results showed that the content of graphite-like P decreased with the annealing temperature and no graphite-like P was retained at 1200℃. The HER activity increased with the annealing temperature and the one annealed at 1200 ℃ had the highest HER activity in an acid medium with an overpotential of 0.266 V at a current density of 10 mA/cm−2. Density functional theory calculations revealed that the pentagon- and nine-membered ring defects formed by the destruction of graphite-P species contributed mainly to the HER activity, which gave a deep insight into the active sites for HER.

Formic acid is one of the key components in green chemistry being involved in energy storage, production of chemical intermediates and fuel components. Therefore the knowledge of its stability is of crucial importance and a systematic study of its decomposition is needed. The kinetics of formic acid decomposition to hydrogen and carbon dioxide was investigated in a laboratory-scale fixed bed reactor at 150–225 °C and atmospheric pressure. Palladium nanoparticles deposited on porous active carbon Sibunit were used as the heterogeneous catalyst. The catalyst was characterized by nitrogen physisorption and high-resolution transmission electron microscopy. The average palladium nanoparticle size was 5–6 nm. The impacts of mass transfer resistance and formic acid dimerization were negligible under the reaction conditions. Prolonged experiments revealed that the catalyst had a good stability. Hydrogen and carbon dioxide were the absolutely dominant reaction products, whereas the amounts of carbon monoxide and water were negligible. The experimental data were described with three kinetic models: first order kinetics, two-step adsorption-reaction model and multistep adsorption-decomposition model of formic acid. The multistep model gave the best description of the data.

Considerable research efforts have been devoted to increase phosphorus (P) availability during aerobic composting. However, there is little discussion weather the dissolved organic carbon (DOC) controls the transformation among P-fractions. Thus, we investigated the changes in DOC compositions and P-fractions during biochar-amended composting (wet weight basis, 5% and 10%). TP content continuously increased since the ‘concentration effect’ during aerobic composting. NaHCO3-Pi, NaOH-Pi and HCl-Pi were main P-fractions, and biochar can improve P-bioavailability by transforming NaOH-Pi and HCl-Pi into NaHCO3-Pi. Structure equation models (SEMs) indicated that biochar enhanced the P-bioavailability through regulating the decomposition of DOC. Our results at least hint that the activation mechanism on P under the influence of DOC during biochar-amended composting.

To establish a cleaner production technology of chromium salt, the pressurized leaching process of chromite ore in 60 wt.% NaOH solution, subsequent separation of a chromium salt from the leached solution and Cr2O3 preparation from the intermediate product BaCrO4 were systematically investigated, and a new highly efficient and economical process for the production of Cr2O3 from chromite ore was established. The results showed that the decomposition of chromate ore could be significantly improved by increasing the temperature, and the Cr leaching rate reached 99% at 240 ℃ for 4 h. Meanwhile, the leaching process was controlled by surface chemical reactions with activation energy (Ea) of 34.3051 kJ/mol and a pre-exponential factor (A) of 6.9560. In the leached liquor, Na2CrO4 was transformed into BaCrO4 through its reaction with Ba(OH)2, Cr separation efficiency could reach as high as 89% in the undiluted leached liquor, while the separated alkali liquor could be effectively recycled for the leaching of chromite ore. Ultimately, a new method for the preparation of Cr2O3 from the intermediate product BaCrO4 was presented by the dissolution and reduction of BaCrO4 with HCl-CH3CH2OH as the reactant. The new cleaner process for Cr2O3 preparation from chromite ore provides an attractive alternative to upgrading the current chromate salt production processes.

Direct synthesis of graphene on insulating substrates is highly desirable for practical applications. Herein, we present a new fabrication method for graphene on quartz which enables the direct growth of high-quality and large-scale graphene films with no metal involved. The growth rate of graphene on insulating substrates was typically extremely slow due to the low catalytic activity and the slow diffusion speed of carbon species on them. Thus, an extra catalyst is required. Instead of metal elements, such as Cu, Ni, and Ga, highly-defective graphene films were applied as the catalyst for methane decomposition. The key feature of our approach is that carbon itself was used as the catalyst for graphene fabrication, which completely avoided the contamination of other elements. As a result, the growth rate of graphene films increased significantly compared to the conventional CVD method. The excellent quality of graphene glass was verified by a series of experimental characterization and the fabrication of a transparent heating device without any transfer process. In addition, the energy barrier of the decomposition of methane was explored using the first principles calculation, which further confirmed the catalytic behavior of highly-defective graphene films.

In this work, different concentrations of coal-water slurry and coal-oil-water slurry were prepared and pyrolyzed at various temperatures of 800–1000 °C. The chemical characteristics and combustion reactivities of chars and the formation mechanism of main gas components of CO, CO2, CH4, and H2 were investigated. With the water content of the coal-water slurry increasing, the formation of CO and CH4 were hindered, while CO2 and H2 were promoted. For the coal-oil-water slurry, oil promoted CH4 and H2 production but inhibited CO and CO2. Moreover, the variation of the nitrogen-containing pyrolytic gas during pyrolysis was studied for various concentrations of coal-water and coal-oil-water slurries at different temperatures. The relative content of HCN and NH3 gradually increased with the increase of pyrolysis temperature and water content. For coal-oil-water slurry, the waste lubricating oil promoted the formation of HCN and NH3, with the relative content of HCN being much higher than that of NH3. To study the mechanism of nitrogen migration during pyrolysis, Lammps was used to simulate pyrolytic behavior of pyrrole and pyridine under N2 and steam atmospheres. The increase in temperature promoted the decomposition of pyrrole and pyridine, thereby promoting the production of HCN and NH3. Finally, the properties and the combustion reactivities of the chars were analyzed. The water and oil content in the coal-water slurry increased the structural ordering degree of chars but decreased the combustion reactivities.

Alumina supported Pd catalyst (Pd/Al2O3) is active for complete oxidation of methane, while often suffers transient deactivation during the cold down process. Herein, heating and cooling cycle tests between 200 and 900°C and isothermal experiments at 650°C were conducted to investigate the influence of NOx on transient deactivation of Pd/θ-Al2O3 catalyst during the methane oxidation. It was found that the co-fed of NO alleviated transient deactivation in the cooling ramp from 800 to 500°C, which was resulted from the in situ formation of NO2 during the process of methane oxidation. Over the Pd/θ-Al2O3, thermogravimetric analysis and O2 temperature programmed oxidation measurements confirmed that transient deactivation was due to the decomposition of PdO particles and the hysteresis of Pd reoxidation, while the metal Pd entities were less active for methane oxidation than the PdO ones. CO pulse chemisorption and scanning transmission electron microscopy characterizations rule out the NO2 effect on Pd size change. Powder X-ray diffraction and X-ray photoelectron spectroscopy characterizations were used to obtain palladium status of Pd/θ-Al2O3 before and after reactions, indicating that in lean conditions at 650°C, the presence of NO2 increases the content of active PdO on the catalyst surface, thus benefits methane oxidation. Homogeneous reaction between CH4, O2, and NOx may be partially responsible for the alleviation above 650°C. The interesting research of alleviation in transient deactivation by NOx, the components co-existing in exhausts, are of great significance for the application.

A highly efficient and stable hydrotalcite-derived Cu-MgAlO catalyst was developed for the partial oxidation of cyclohexane with molecular oxygen. The physical-chemical properties of Cu-MgAlO catalysts were studied, and the results indicated that the copper component had been successfully introduced into the hydrotalcite unit layer structure. The catalytic reaction results showed that copper as the active species could activate C-H bond and effectively promote the decomposition of cyclohexyl hydroperoxide (CHHP) to KA oil. 8.3% of cyclohexane conversion and 82.9% of selectivity for KA oil were obtained over 9%Cu-MgAlO catalyst at 150 °C with 0.6 MPa of oxygen pressure for 2 h. Especially, its catalytic performance was still stable after five runs.

A once overlooked source of electrolyte degradation incurred by dissolved manganese (II) species in lithium-ion batteries has been identified recently. In order to deactivate the catalytic activity of such manganese (II) ion, 1-aza-12-crown-4-ether (A12C4) with cavity size well matched manganese (II) ion is used in this work as electrolyte additive. Theoretical and experimental results show that stable complex forms between A12C4 and manganese (II) ions in the electrolyte, which does not affect the solvation of Li ions. The strong binding effect of A12C4 additive reduces the charge density of manganese (II) ion and inhibits its destruction of the PF6− structure in the electrolyte, leading to greatly improved thermal stability of manganese (II) ions-containing electrolyte. In addition to bulk electrolyte, A12C4 additive also shows capability in preventing Mn2+ from degrading SEI on graphite surface. Such bulk and interphasial stability introduced by A12C4 leads to significantly improved cycling performance of LIBs.

Cold-drawn pearlitic steel wire is irreplaceably used in industry owing to its outstanding mechanical property which is dominated by the cementite/ferrite (Fe3C/Fe) interfaces in the material. However, the fine structures of the Fe3C/Fe interfaces in the deformed wires are less known to date. In this work, transmission electron microscopic investigation was performed on the atomic structures of the interfaces with the Isaichev orientation relationship (OR) in the wires with progressive deformation strains. In addition to the effect of the dislocation/interface interactions, this work revealed that the deformation-induced partial decomposition of cementite plays an important role in the interface reconstruction during deformation. The interfacial carbon vacancies generated by cementite decomposition and particularly, the amorphization of cementite layers in the sample with e > 1 could effectively annihilated the interfacial dislocations and consequently relaxed the interfacial stress. The correlations between the interface structure changes and the mechanical properties of the wires were discussed.

Summary Conventional aqueous electrolytes suffer from a narrow voltage window due to water decomposition. Highly concentrated electrolytes expand the voltage window; however, they are limited by high cost and potential toxicity. Here, we develop a hydrogen bond-anchored electrolyte by introducing sulfolane as hydrogen bond acceptor to limit water activity. The designed electrolyte expands the voltage window to 3.4 V (1.3–4.7 V versus Li+/Li) and forms a hierarchical anode-electrolyte interphase to suppress the hydrogen evolution reaction. An aqueous Li4Ti5O12/LiMn2O4 full cell achieved 141 W h kg−1 for 300 cycles at 1 C and 125 W h kg−1 for 1,000 cycles at 5 C with a high Coulombic efficiency of 99.5%–99.9%. On-line electrochemical mass spectroscopy shows negligible hydrogen/oxygen gas evolution upon cycling, further confirming the stability of the designed electrolyte. This work demonstrates a rational and effective approach to suppress the hydrogen evolution reaction and achieve stable high-voltage aqueous batteries.

This work used CO2 as a co-reaction gas to realize in-situ deoxygenation of the bio-oil produced from microwave pyrolysis of biomass, and the mechanisms were thoroughly analyzed. Results showed that the bio-oil obtained at 550 °C (N2 atmosphere) had the highest yield of 29.24 wt.% with the higher heating value (HHV) of 20.27 MJ/kg. The introduction of CO2 atmosphere reduced the oxygen content of the bio-oil by 12.68 wt.% and increased the HHV by 26.43%. The oxygen mass balances demonstrated that the oil-O decreased by 31.45%, and the gas-O increased by 29.28% at CO2 atmosphere. The specific components in the bio-oil and pyrolytic gas were characterized. Furans in the bio-oil could react homogeneously with CO2 to generate CO at CO2 atmosphere, which was the main route to realize in-situ deoxygenation of the bio-oil. Meanwhile, stearic acid was selected as a model compound of the bio-oil to verify the action mechanisms of CO2 atmosphere. CO2 inhibited the decomposition of stearic acid to reduce the polycyclic aromatic hydrocarbons (PAHs) content in the bio-oil and promoted the generation of alkenes and CO. This study provides a novel perspective for the production of low-oxygen and high-quality bio-oil from biomass using CO2 reaction atmosphere.

Cellulose accounts for the largest proportion of lignocellulosic biomass. Herein, experimental and simulation studies are used to deeply understand the kinetic characteristics of the thermal decomposition of α-cellulose. The simulated data is in good agreement with the experimental data in the aspects of the conversion and the conversion rate versus temperature. The decomposition of α-cellulose, mainly occurring at 270–420 °C, induced an apparent activation energy ranging from 175.42 kJ/mol to 197.73 kJ/mol at a conversion of 10–90%. With 0.1–0.2 wt% K or Ca impregnation into the α-cellulose, the mean activation energy for pyrolysis was lowered (from 181.47 kJ/mol (for α-cellulose) to 141.11 kJ/mol (for 0.2 wt% K/α-cellulose) and 159.46 kJ/mol (for 0.1 wt% Ca/α-cellulose)) and higher amounts of liquid and gas products were produced. Furthermore, the addition of potassium and calcium increased the production of lower molecular weight components, such as furfural and its derivatives. The kinetic parameters of the α-cellulose pyrolysis were determined based on a nonlinear least-squares regression of the experimental data assuming first-order kinetics and correlated with the simulated result. The kinetic rate constants indicate that the predominant reaction pathway is from α-cellulose into a liquid product, rather than from α-cellulose into a gas product.

On-site produced hydrogen from ammonia decomposition can directly fuel solid oxide fuel cells (SOFCs) for power generation. The key issue in ammonia decomposition is to improve the activity and stability of the reaction at low temperatures. In this study, proton-conducting oxides, Ba(Zr,Y) O3-δ (BZY), were investigated as potential support materials to load Ni metal by a one-step impregnation method. The influence of Ni loading, Ba loading, and synthesis temperature, of Ni/BZY catalysts on the catalytic activity for ammonia decomposition were investigated. The Ni/BZY catalyst with Ba loading of 20 wt%, Ni loading of 30 wt%, and synthesized at 900 °C attained the highest ammonia conversion of 100% at 600 °C. The kinetics analysis revealed that for Ni/BZY catalyst, the hydrogen poisoning effect for ammonia decomposition was significantly suppressed. The reaction order of hydrogen for the optimized Ni/BZY catalyst was estimated as low as −0.07, which is the lowest to the best of our knowledge, resulting in the improvement in the activity. H2 temperature programmed reduction and desorption analysis results suggested that a strong interaction between Ni and BZY support as well as the hydrogen storage capability of the proton-conducting support might be responsible for the promotion of ammonia decomposition on Ni/BZY. Based on the experimental data, a mechanism of hydrogen spillover from Ni to BZY support is proposed.

An effective decontamination method for soils remediation is a long-standing challenge. Herein, hydrogen peroxide (H2O2) was spontaneously produced in thin films generated by evaporating almost all the water. H2O2-sensitive test strips and oxidation of 2-hydroxybenzophenone to 2-hydroxyphenyl benzoate confirmed the generation of H2O2. Experiments in which reaction time and temperature were varied and established dependence of H2O2 production on the long-lasting thin films. H2O2 production was independence of irradiation and oxygen from air or dissolved oxygen. Spin-trapping probe experiments suggested that electric fields at the thin interfacial films enabled OH- to hydroxyl radicals and further recombination to H2O2. As a proof-of-principle experiment, perfluorooctanoic acid (PFOA) was effectively degraded on the thin films without catalysts and UV irradiation could further facilitate the degradation. A degradation mechanism was proposed involving the PFOA radicals on thin interfacial films and the subsequent decomposition of the radicals with successive loss of CF2. These findings have important implications for the development of decontamination method for soils remediation based on thin films, because thin film formats are ubiquitous at the surface of soils and when aerosols falling onto a substrate.

The complexes of Co (II), Ni (II), and Zn (II) with manganese were synthesized by co-precipitation techniques such as fumarates and tartrates. The formation of these dicarboxylate complexes characterized by elemental analysis, infrared spectroscopy, and X-ray powder diffraction studies. The thermal decomposition behaviors of these complexes were investigated using thermal analysis (TGA, DTG, and DTA) and d. c. electrical conductivity measurements under normal atmosphere. Based on conductivity measurements and isothermal studies, a probable mechanism for the decomposition was proposed. After dehydration, the anhydrous complexes decompose to yield respective carbonate intermediate in the temperature range 200 – 350 °C. Decomposition of this carbonate species to the formation of the respective spinel in the temperature ranges 350 – 500 °C. The infrared spectra and X-ray powder diffraction studies were made for the identification of intermediate products. The X-ray diffraction studies of the end product indicate that spinel such as CoMn2O4, NiMn2O4, and ZnMn2O4 formed as a final product. The electrical conductivity measurements were found to give additional information on the solid-state reaction as compared to that obtained from conventional thermal techniques (such as TGA, DTG, and DTA).

Facilitating polysulfide conversion by electrocatalysis is a promising strategy to suppress shuttle effect in lithium-sulfur (Li-S) batteries, yet the active sites in electrocatalysts are gradually passivated by continuous formation of Li2S passivation layer over cycling, making it challenging to achieve steady conversion of sulfur species. Herein, a strategy of reactive Li2S collaborated with dual-directional Fe3C electrocatalyst is proposed to achieve fast and continuous conversion of sulfur species for drastically boosting the performance of Li-S batteries. During the reduction process, reactive Li2S with unique three-dimensional porous structure is precipitated on Fe3C surface, which not only shortens ion/electron diffusion path but also exposes and retains more active sites in Fe3C. While for the following oxidation process, Fe3C also promotes the decomposition of reactive Li2S to refresh electrocatalyst surface. Therefore, the high catalytic activity of Fe3C is well retained during the entire electrochemical process, as verified by comprehensive experimental and theoretical calculation results. Eventually, Fe3C enables stable operation of high-areal-capacity Li-S batteries (> 6.0 mAh cm−2) under a wide-temperature range (-10 to 40 °C). Our strategy of coupling reactive Li2S with a bidirectional electrocatalyst provides a new avenue for developing high-energy and wide-temperature Li-S batteries.

In this study, the effect of unintentional nitrogen incorporation on n-type doping of β-Ga2O3 films grown by plasma-assisted molecular beam epitaxy has been demonstrated. The nitrogen atoms, with a concentration as high as 2×1019 cm-3, are confirmed to originate from the decomposition of the pyrolytic boron nitride (PBN) crucible in the plasma source. These atoms act as acceptors in β-Ga2O3 and severely compensate the Si-donors, thus, hindering the generation of n-type β-Ga2O3. Instead, a quartz (SiO2) crucible free of nitrogen atom can overcome this issue, leading to the successful generation of n-type β-Ga2O3 with tunable electron concentration in the range 5.0×1016-2.6×1019 cm-3.

Traditional hard/soft template approaches to hollow structures suffer from tedious procedures and time-consuming. Compare to these methods, self-template approaches usually gain advantages of step-economy. Herein, solid spherical Ni-glycolate/Ni microspheres were initially synthesized by reacting nickel (II) with ethylene glycol at high temperature. The source of nickel (II) has determinable impact on the formation of Ni-glycolate/Ni. Specially, nickel acetate as sources yielded Ni-glycolate/Ni, while nickel nitrate as precursor cannot. The plausible reason for this result can be attributed to the different acidity of the system caused by the dissolution of nickelacetate and nickel nitrate. By reacting with thioacetamide (TAA) under solvothermal condition and heat treatment, the Ni-glycolate/Ni microspheres were further employed as self-template for direct the formation of hollow NiS microspheres. The driving force for converting Ni-glycolate/Ni into hollow NiS could be attributed to Kirkendall effect resulted from the different diffusion rates of nickel ions (from Ni-glycolate/Ni) and sulfur ions from the decomposition of TAA. When applied as electrode material of supercapacitors, the formed hollow NiS microspheres exhibited a specific capacitance of 1674 F/g at 1 A/g with excellent rate capability and cycling performance. The corresponding asymmetric device of NiS//AC delivered a high energy density of 43.3 Wh/kg at the power density of 850.3 W/kg. These achievements pave innovative synthetic approach to hollow structures for many other practical applications.

Assuming a series-type microbial fuel cell (MFC) that sequentially consumes organic acid components, the effects of the electrode material, external resistance, and temperature of MFC on the decomposition characteristics of acetate and propionate were investigated. As to electrode materials, propionate decomposition required less time in carbon cloth (CC) than that in carbon felt (CF), and maximum power was produced higher in CC than that in CF as well as acetate substrate. When the external resistance of 1000 Ω was replaced with 100 Ω or 10 Ω, both the decomposition rate and maximum power in propionate were lower than those in acetate, respectively. The time required for acetate decomposition at the temperature of 30 °C and 37 °C was 14.8 and 19.4 h, while 25.3 and 17.2 h in propionate at 30 °C and 37 °C, respectively. The microbial community changed significantly between 30 °C and 37 °C of the temperature.

In this study, we developed an improved comprehensive pyrolysis scheme by modifying the bio-oil species and gas species fractions, increasing the carbon fraction in the char, and combining and changing the metaplastic decompositions for energy analysis. The two-fluid model (TFM) framework was used to simulate pyrolysis in a two-dimensional tubular reactor, and 10 g of 1500-μm-sized pinewood particles was used as biomass feedstock. Pyrolysis was performed at 400 °C−600 °C with an average heating rate of 115 °C/min. The improved scheme was evaluated against recent comprehensive pyrolysis schemes with respect to decomposition characteristics. The pyrolysis product yields and compositions predicted by the improved model accorded with experimental results. Moreover, the energy contents and distributions of pyrolysis products were successfully estimated, and the relative errors of bio-oil, gas, and char energies were 0.61%, 9.54%, and −3.76%, respectively. The energy distributions were more dominant influenced by the pyrolysis product yields than by the energy density.

Catalytic ammonia (NH3) decomposition has been identified as a COx-free, sustainable hydrogen production method for fuel cell applications. In this study, the performance of plasma–catalyst-based NH3 decomposition over ruthenium (Ru/Al2O3) and soda glass (SiO2) catalytic materials at atmospheric pressure and ambient temperature was investigated. NH3 decomposition reactions were conducted in a dielectric barrier discharge plasma plate-type reactor. NH3 was fed into the plate catalytic microreactor at flow rates of 0.1–1 L/min and plasma voltages of 12–18 kV. Compared to plasma NH3 decomposition without a catalyst, plasma–catalyst-based NH3 decomposition showed a significant enhancement of the hydrogen production rate and energy efficiency. Furthermore, the hydrogen concentration results obtained over the Ru/Al2O3 catalyst were higher than those over the SiO2 catalyst because Ru/Al2O3 possesses good electronic properties and exhibits high sensitivity to NH3 decomposition. In addition, the resulting plasma heat enhanced the activation of the catalytic material, subsequently leading to an increase in the hydrogen production rate from NH3. The maximum conversion rates were 85.65% and 84.39% for Ru/Al2O3 and SiO2, respectively. Moreover, the energy efficiency of NH3 decomposition over the Ru-based catalyst material was higher than that over the SiO2 material. The presence of the catalyst active sites and plasma enhanced the mean electron energy, which could enhance the dissociation of NH3. It can be concluded that the SiO2 material can be utilised as a catalyst and that its combination with plasma accelerates the decomposition process of NH3 and incurs a lower cost compared to Ru materials.

Hydrogen storage in solid-state materials is believed to be a most promising hydrogen-storage technology for high efficiency, low risk and low cost. Mg(BH4)2 is regarded as one of most potential materials in hydrogen storage areas in view of its high hydrogen capacities (14.9 ​wt% and 145–147 ​kg ​cm−3). However, the drawbacks of Mg(BH4)2 including high desorption temperatures (about 250 ​°C–580 ​°C), sluggish kinetics, and poor reversibility make it difficult to be used for onboard hydrogen storage of fuel cell vehicles. A lot of researches on improving the dehydrogenation reaction thermodynamics and kinetics have been done, mainly including: additives or catalysts doping, nanoconfining Mg(BH4)2 in nanoporous hosts, forming reactive hydrides systems, multi-cation/anion composites or other derivatives of Mg(BH4)2. Some favorable results have been obtained. This review provides an overview of current research progress in magnesium borohydride, including: synthesis methods, crystal structures, decomposition behaviors, as well as emphasized performance improvements for hydrogen storage.

Lithium metal batteries have obtained increasing interest due to their high specific capacity. Nonetheless, the growth of lithium dendrites brings safety risks to batteries and further deteriorates the performance. Herein, we explore diethyl phenylphosphonite (DEPP) as the electrolyte additive to alleviate this problem. DEPP can be preferentially decomposed than carbonate solvents to form the stable interface between electrolyte and lithium anode for inhibiting the dendrite growth. As expected, the symmetrical LiIILi cells could achieve a stable cycling performance with 200 h at 1 mA cm−2. Moreover, DEPP can be preferentially oxidized on the surface of lithium cobalt oxides (LiCoO2) to form a dense cathode electrolyte interphase (CEI) film for suppressing the continuous oxidative decomposition of the electrolyte and eliminating the adverse effects of HF on the battery. This endows LiCoO2IILi full battery with the enhanced cycling and rate performance.

The functional copper nanocomposites (Cu NCs) have received increasing attention in the environmental catalysis application for wastewater treatment due to their superior catalytic activity and reactivity. However, overcoming the pH limitations towards the neutral and alkaline wastewater remains a tricky challenge. In this work, we demonstrate a green strategy to synthesize Cu NCs with coexistence of active Cu, Cu2O and ZrO2 by self-propagating combustion of metallic glassy ribbons, which exhibit the extremely superior catalytic performance for degradation reaction, providing full conversion of organic dyes completely to the environmental friendly small species (efficiency > 99%) under acidic, neutral and alkaline conditions. Compared with all other catalysts developed thus far, the novel Cu NCs catalysts with more active sites present much enhanced catalytic capability of degradation efficiency without the use of any chemical reagents for neutral and alkaline organic dye solutions. The possible decomposition pathways of organic dyes for different pH systems were systematically investigated. More importantly, the two kinds of catalytic mechanism related to high reactivity of nanoscale Cu/Cu2O and strong oxidizing capability of activated •OH /•O2− radicals can also be successfully confirmed under different pH conditions. The green synthetic approach can be extended to design the various M-based nanocomposites (M = Fe, Co, Ni, Ag, Pd) as efficient catalysts for the functional applications of many chemical reactions.

The interaction of organic carbon (OC) with clay and metals stabilizes soil carbon (C), but the influence of specific clay-metal-OC assemblages (flocs) needs further evaluation. This study aimed to investigate the stability of flocs in soil as affected by external C inputs. Flocs representing OC-mineral soil fractions were synthesized using dissolved organic C (DOC) combined with kaolinite (1:1 layer structure) or montmorillonite (2:1 layer structure) clays in the absence or presence of two levels of Fe (III) (named low or high Fe). Flocs were mixed with soil (classified as Luvisol) and incubated with or without 13C labelled plant residue (i.e., ryegrass) for 30 days. The CO2 emissions and DOC concentrations as well as their 13C signatures from all treatments were examined. Total C mineralization from flocs was approximately 70% lower than non-flocced DOC. The flocs made with montmorillonite had 16–43% lower C mineralization rate than those made with kaolinite with no Fe or low Fe. However, when flocs were made with high Fe, clay mineralogy did not significantly affect total C mineralization. A positive priming effect (PE) of flocs on native soil OC was observed in all treatments, with a stronger PE found in lower Fe treatments. The high-Fe clay flocs inhibited ryegrass decomposition, while the flocs made without clay had no impact on it. Interestingly, flocs significantly decreased the PE of ryegrass on native soil OC decomposition. These results indicate that the adsorption of DOC onto clay minerals in the presence of Fe (III) stabilizes it against decomposition processes and its stability increases as Fe in flocs increases. Flocs also protect soil OC from the PE of external degradable plant C input. This study showed that Fe level and clay mineralogy play an important role in controlling soil C stability.

The cyclopropanation of alkenes through the transition-metal-catalyzed decomposition of diazo compounds is a powerful and straightforward strategy to produce cyclopropanes. Nevertheless, the appeal of further application of this strategy is tempered by the potentially explosive nature of the diazo substrates. Therefore, it is highly desirable to develop sustainable and operationally safe surrogates for diazo compounds. In this Synpacts article, we discuss recent advances on the cyclopropane syntheses through the catalytic cyclopropanation of alkenes and metal carbenes generated in situ from nondiazo precursors as well as highlight our recent progress on the unprecedented molybdenum-catalyzed deoxygenative cyclopropanation reaction of 1,2-dicarbonyl or monocarbonyl compounds.

Activation of small molecules is one of the important research topics for last decade. Activation of nitrogen is one among the important small molecule. This work presents a DFT study of the adsorption properties of nitrogen molecule over group 8 metal-borazine complex. Using B3LYP theory and 6-31G*/LANL2DZ basis sets, the different mode of adsorption of dinitrogen over the metal-borazine complex has been studied. In all the case, dinitrogen has adsorbed over the metal-borazine complex without undergoing any deformation and decomposition. Vibrational analysis, NPA and FMOs analysis afford significant understanding into their bonding and reactivity pattern. All the complexes show very strong binding towards dinitrogen and lead to activation of nitrogen molecule with less energy barrier. It has been observed that dinitrogen is highly activated in the case of Os-complex. The results show that group 8 metal-borazine complexes are a potential nitrogen trapper and good choice of complexes for activating the nitrogen molecule.

A systematic study of halogenate(I/III) anions with polyatomic ligands is presented. The bis(perfluoro-tert-butoxy) halogenates(I) [X(OC4 F9 )2 ]- , X=Cl, Br, I, of chlorine, bromine, and iodine are prepared as their tetraethylammonium salts and characterized with IR, Raman, and NMR spectroscopic methods, as well as single-crystal X-ray diffraction analyses. Spectroscopical data are supported by quantum-chemical calculations. Additionally, the bonding situation of the species in question are analyzed and discussed. Furthermore, the oxidation to the corresponding halogenate(III) derivatives was studied. For [Br(OC4 F9 )2 ]- , oxidation with elemental fluorine gave [BrF2 (OC4 F9 )2 ]- . Iodide was directly oxidized by ClOC4 F9 to the IIII species [I(OC4 F9 )4 ]- , which is a surprisingly inert anion that might be used as a weakly coordinating anion (WCA) in the future. For [Cl(OC4 F9 )2 ]- , the decomposition products of the synthetic approaches towards a chlorine(III) system were analyzed.

Cobalt ferrite nanoparticles were obtained by the green synthesis method using extracts of grape peel and grape pulp. The obtained samples have been investigated by means of X-ray diffraction (XRD) analysis, scanning electron microscope (SEM), and Mossbauer spectroscopy. All samples contain pure CoFe2O4 with the cubic spinel structure of the space group Fd3m. XRD analysis indicates that cobalt ferrite nanoparticles synthesized using grape peel extract and grape pulp extract have crystallite sizes of ~ 5 and ~ 25 nm, respectively. Cation distribution and crystalline structure parameters of the samples were calculated on the basis of Mossbauer spectroscopy data. After annealing, the CoFe2O4 sample obtained with grape pulp extract has a higher degree of inversion than that obtained with grape peel extract. The decrease in the degree of inversion is related to a decrease in the average size of crystallites. The CoFe2O4 sample synthesized using grape peel extract is a more active catalyst for the decomposition of hydrogen peroxide. The first-order rate constants are 1.11·10−4 s−1 and 3.43·10−4 s−1 for the CoFe2O4-pulp and CoFe2O4-peel samples, respectively. A 100 mM H2O2 solution was decomposed to 97.4%. The surface morphology of the cobalt ferrites remains unchanged after the catalytic decomposition of H2O2. The synthesized cobalt ferrites can be used in Fenton processes as stable magnetic catalysts.

Pressure of gigapascal (GPa) is a robust force for driving phase transitions and chemical reactions with negative volume change and is intensely used for promoting combination/addition reactions. Here, we find that the pressure gradient between the high-pressure region and the ambient-pressure environment in a diamond anvil cell is an even stronger force to drive decomposition/elimination reactions. A pressure difference of tens of GPa can "push" hydrogen out from its compounds in the high-pressure region to the environment. More importantly, in transition metal hydroxides such as MnOOH, the protons and electrons of hydrogen can even be separated via different conductors, pushed out by the high pressure, and recombine outside under ambient conditions, producing continuous current. A pressure-gradient-driven battery is hence proposed. Our investigation demonstrated that a pressure gradient is a special and powerful force to drive decomposition and electrochemical reactions.

Biowaste derived ethanol is an important feedstock for carbon neutral hydrogen production. It is liquid at atmospheric conditions, has a high hydrogen to carbon ratio, and it can be generated from ...

The mechanisms of hydroxyl radical (·OH) degradation of disperse red 73 (DR73) dye were investigated using density functional theory (DFT) calculations. Comparative feasibility of ·OH attack at the azo (N=N) site or on a > C–N group was examined based on their energies with a view to determine the more preferred pathway for DR73 degradation and predict its degradation products. Further decomposition of the cleavage products by ·OH radical through processes such as deamination and loss of molecular nitrogen was also examined. The results showed that ·OH radical attack on DR73 is more favourable via the azo (N=N) site. However, subsequent rupture of the N=N bond was found to be kinetically and thermodynamically less favourable compared to the C–N bond rupture arising from the attack of the radical on a ring carbon attached to the azo group. Introduction of water (as a solvent) was found to produce an accelerating and stabilising effects on the N=N bond cleavage mechanism, but an inhibitory and destabilising effects on the C–N counterpart. Deamination and nitrogen evolution reactions of the primary degradation products upon further ·OH radical attack were found to be kinetically and thermodynamically feasible.

In this study, 2D TiC nanosheets were successfully synthesized by reacting carbon black and Ti2AlC in a molten NaCl/KCl eutectic salt. The effects of salt content and ratio of raw materials on the phase composition and purity of TiC products were systematically investigated. Results showed that carbon black enhanced the total decomposition of Ti2AlC to TiC, Al, and Al3Ti at 1100 °C. The introduction of molten salt ensured the formation of TiC nanosheets. Excess carbon influenced the synthesis of high TiC content by removing the Al and Al3Ti by-products. TiC nanosheets had a thickness of approximately 10–20 nm and a length of approximately 150–200 nm. A possible synthesis mechanism of TiC nanosheets was proposed.

In this work, it was shown that low-temperature plasma initiated in liquid-phase media in the discharge gap between the electrodes is capable of efficiently decomposing hydrogen-containing molecules of various organic compounds and their mixtures with the formation of gaseous products in which the proportion of hydrogen is more than 90% according to gas chromatography data. In the course of work, an experimental setup for hydrogen production was designed and manufactured, which includes a steel reaction chamber with a cooling jacket, a power supply with adjustable parameters, an ultrasonic generator and transducer, and a gas extraction system. Optimal conditions for the production of hydrogen (yield and selectivity) have been found, and principles have been developed for the automation of the process and the design of a semi-continuous pilot plant in order to increase productivity. The reaction products and the purity of the obtained hydrogen are characterized by a set of instrumental methods of physicochemical analysis, including gas and liquid chromatography, microscopy, calorimetry, and other methods. Preliminary estimates of the energy efficiency, calculated taking into account the heat of combustion of hydrogen and the initial substances, as well as the consumption of electricity, showed an efficiency level of about 60–70%, depending on the composition of the initial mixture. Theoretical calculations of the voltage and current of the discharge were also carried out during the simulation of the process, which are consistent with the experimental data. A by-product of hydrogen production by the acoustoplasma discharge method during the decomposition of organic liquids is carbon, which is formed in the form of agglomerates of nanoparticles of various structures and is deposited during the reaction at the bottom of the reaction chamber. As shown by the results of analyzes and stoichiometric calculations, the formation of these by-products consumes most of the carbon and oxygen contained in the molecules of the initial liquid, thereby the resulting gaseous mixture is significantly enriched in hydrogen. The resulting nanoparticles and their agglomerates can also be used as fillers, dyes, components of composite materials.

Conversion of low value agricultural residues to better-quality products e.g. biofuel, bioproducts can solve the issues related to energy crisis as well as environmental challenges. Torrefaction, a thermochemical pretreatment was employed on canola residue (CR) to augment the physicochemical properties of biomass for heat and energy applications. In the present study, the effects of microwave torrefaction on canola residue have been investigated for the following operating parameters: microwave power (250–450 W), residence time (10–20 min), and feeding load (70–110 g). Box Behnken design method was used to design the experiments and find the interaction between process parameters. Both mass and energy yields diminished with rise in microwave power and torrefaction reaction time. The results show that the carbon content significantly increased with degree of torrefaction while oxygen content had a reverse trend, therefore the atomic ratio of torrefied biomass reduced remarkably. Torrefied biomass shows higher carbon percentages than that for the bituminous coal. In addition, a noticeable decrease in volatile matter was observed with growth in torrefaction severity and thus increased fixed carbon content. The higher heating value (HHV) was boosted up by 26% (promoted from 17.8 MJ/kg to 22.4 MJ/kg). HHV of highly torrefied canola residue is very close to bituminous coal. Fourier transform infrared spectroscopy (FTIR) analysis showed that surface functional groups for example O H, C H, and C O decreased with torrefaction severity indicating the improvement of hydrophobicity of torrefied biomass. Scanning electron microscopy (SEM) results represent a more porous structure at highest torrefaction conditions which happened due to thermal cracking and decomposition of lignin and decreased the grinding energy by 89% compared to that for raw biomass. Moreover, inductively coupled plasma-mass spectrometry (ICP) analysis data showed that concentrations of minerals, alkaline and other essential element amplified with degree of torrefaction. The influence of microwave power was the highest on properties of torrefied biomass, followed by residence time and feeding load. The optimum torrefaction conditions were found at 450W with 90 g feeding load for residence time of 20 min.

The investigation of the primary combustion products of boron-based fuel-rich propellants is conducive to understanding the mechanism of the two-stage combustion process and provides important information for the prediction and organization of secondary combustion processes. The present investigation methods include numerical simulation and experimental analysis. The former deviates considerably from the actual conditions. The latter is currently a reliable and practical method, although it is difficult to quantify when the components are complex. In this work, SEM, LPSA, XRD, XPS, IC, ICP–MS, AAS, EDS, and chemical analysis methods were employed to qualitatively and quantitatively analyze the 3 solid products (aggregations, condensed-phase products, and flocculent products) at 1, 5, and 10 bar. GC, GC–MS, and IC combined with chemical tests were adopted to investigate the gaseous products (including chlorine-containing gas) for the first time. The solid products primarily included B2O3, B(HO)3, unburned boron, KB5O8(H2O)4, KCl, C, NH4Cl, NH4Mg(H2O)6Cl3, B13C2, Fe3O4, Mo, MgO, Mg(OH)2, MoO3, C3N4, BN, MgCO3(H2O)3 (or MgCO3), MoO2, Fe4(Fe(CN)6)3, and FeB (or BFe4), and the first 7 were dominant. The reaction degree of boron was less than 50 wt% (increasing with increasing pressure), indicating the significance of the secondary combustion process. The reacted boron was likely to react with O and C but not with N. The generated B2O3 vapor easily combined with H2O to form B(HO)3 or reacted with KCl (from the thermal decomposition of KP) and H2O to produce KB5O8(H2O)4 after cooling. There was less B13C2 (its content increased with increasing pressure, resulting in increases in particle size), since it was easily oxidized to generate B2O3. NH4Cl was produced by the oxidation-reduction reaction between the NH3 and HClO4 released from large-sized AP, and some of it crystallized with MgCl2 and H2O to form NH4Mg(H2O)6Cl3. The gaseous products primarily included N2, H2, CO, CH4, CO2, C2H4, C2H2, HCl, C4H6, C3H6, Cl2, C6H6, and other hydrocarbons. N2 and H2 had the highest content. The N2 content increased with increasing pressure, while the content of the combustible gases decreased, indicating that high pressure promotes the propellant reaction. The results also show that high pressure was conducive to the low-temperature decomposition of AP (producing more HCl and Cl2) and the reaction of boron and hydrocarbons (generating more B13C2), while it had an adverse effect on the C reaction (producing less COx and mostly CO). Nevertheless, the increasing pressure had little effect on the combustion product components but did affect the content within the pressure range.

The pyrolysis and combustion mechanism of the hydrocarbon fuel has important scientific and practical significance. However, it is difficult to detect the whole intermediates and products using traditional methods, which brings trouble to the analysis of the reaction process. In this paper, the microscopic reaction mechanism and the main products of n-eicosane (C20H42) were simulated based on the reactive force field molecular dynamics (ReaxFF-MD). The effects of temperature (2000–3500 K) and oxygen on the initial decomposition, the distribution of main products, and the reactive pathways of C20H42 fuel were studied to determine its reaction mechanism. The initial decomposition of C20H42 was mainly initiated by small alkyl radicals in pyrolysis, and by the oxygen-containing radicals in combustion. The participation of oxygen had a greater effect on accelerating the decomposition reaction. The reactions involving oxygen of C20H42 initial decomposition accounted for 87.5% of the total reactions at 2000 K. Moreover, the detailed distribution and formation pathways of the main products of H2, C2H4, CH4, H2O, CO, and CO2 were depicted to construct the overall reaction mechanism of C20H42. •H radical formed from the composition of C2H4 was exactly consistent with the •H radical consumed by the generation of CH4 and H2 in the pyrolysis stage. The feasibility of the simulation method was verified by the result of thermal analysis. The results are helpful for further research on the reaction mechanism of hydrocarbon fuels.

Fine root decomposition plays an essential role in the nutrient cycle and energy transfer in terrestrial ecosystems, and changes in decomposition induced by nitrogen (N) deposition have become a global concern. However, patterns of fine root decomposition with N application are still scattered, and the dominant factors regulating decomposition are still controversial. Here, we aimed to explore general patterns and key drivers of decomposition in temperate forests with N application. From 20 studies, we synthesized 123 records of fine root decomposition in temperate forests where N was applied. We explored the overall effect of decomposition with N application and the variation in decomposition among N application rates, N forms, fertilization condition of root growth and decomposition (FF, from fertilized to fertilized conditions, and UFF, from unfertilized to fertilized conditions), tree functional types and soil depth. The dominant factors of decomposition were identified using regression. Our results showed that N application decreased fine root decomposition. Specifically, decomposition decreased at the application rate of 100–150 kg N ha‒1 yr‒1, under NH4NO3 application, in broadleaf trees and in deep layers, attributable to the inhibited microbial enzyme activity. Decomposition decreased in FF, likely resulting from home-field advantage (HFA) effects. Multiple regressions showed that initial lignin content was the most important factor determining decomposition. Our results suggested that inhibited microbial enzymes were associated with decreased decomposition under N application in temperate forests. Additionally, our results confirmed the importance of initial root traits, such as lignin, in regulating decomposition.

Nitric oxide (NO) and sulfur dioxide (SO2) are the major environmental pollutants being generated in the steel industry. More than half of NO and SO2 are emitted from sinter plants. Due to the catalytic effect of CaO in the sinter mix on the formation of NO and SO2, it might differ from that in the combustion of raw coals. In the combustion of raw coals, both NO and SO2 were formed in the temperature range of 473 K (200 °C) to 1623 K (1350 °C). In the case where the content of endogenous CaO in coal ash was high, the formation of SO2 was significantly reduced below 1473 K (1200 °C). In the case of the sinter mix, NO was formed in the temperature range of 473 K (200 °C) to 1173 K (900 °C) and the conversion of N to NO was increased by the catalytic effect of CaO in the sinter mix. Most of the SO2 was formed above 1473 K (1200 °C). The CaO present in the sinter mix reacted with the SO2 generated below 1473 K (1200 °C) to form CaSO4, the stability of which was maintained until 1473 K (1200 °C); thus, the conversion of S to SO2 was reduced. Based on the coal composition and functionalities of nitrogen and sulfur in coals, the indices of NO and SO2 were proposed to predict the conversion of N to NO and S to SO2, respectively. The increased heating rate shifted the formation temperature range of NO to higher temperatures and increased the formation of SO2 by the thermally activated decomposition of CaSO4.

Industrial sour gas flaring is difficult to operate appropriately, especially when the gas stream contains high concentrations of sulfur compounds such as hydrogen sulfide and mercaptans. However, most of the detailed combustion mechanisms for hydrocarbons are too complicated, and the computation can be time consuming. In addition, most of the available combustion mechanisms for sulfur compounds are not tailored for sour gas flaring. A reduced combustion mechanism for sour gas will be highly desirable for practical application. In this work, a reduced combustion kinetic mechanism for sour gas combustion, namely the H&S mechanism, was created. This mechanism was validated against experimental data from the literature with proven accuracy. During mechanism analysis, it was found that the addition of H2S had a significant impact on the radical pool. A small amount of H2S leads to a fast buildup of H, OH, and O radicals and a rapid decomposition of CH4. The impact on ignition delay time due to an increase in H2S concentration by 3 vol. % was also analyzed. The impact needs to be compensated by the addition of supplementary fuel. This research will contribute to the clean combustion of sour gas, especially sour gas flares.

Ni-EDTA is widely present in electroplating effluents. It cannot be effectively removed by traditional wastewater treatment methods due to its chemical stability. In this study, copper sulphide/cup...

Funding Information: Open access funding provided by Aalto University. This work was funded by the Academy of Finland's Flagship Programme under Projects No. 318890 and 318891 (Competence Center for Materials Bioeconomy, FinnCERES). Publisher Copyright: © 2021, The Author(s). This study focuses on the investigation of the extent of the γ-valerolactone (GVL) hydrolysis forming an equilibrium with 4-hydroxyvaleric acid (4-HVA) in aqueous solutions over a wide pH range. The hydrolysis of a 50 wt% GVL solution to 4-HVA (3.5 mol%) was observed only at elevated temperatures. The addition of sulfuric acid (0.2 × 10–5 wt% to 6 wt%) at elevated temperatures (150–180 °C) and reaction times between 30 and 180 min caused the formation of 4 mol% 4-HVA. However, with decreasing acidity, the 4-HVA remained constant at about 3 mol%. The hydrolysis reactions in alkaline conditions were conducted at a constant time (30 min) and temperature (180 °C) with the variation of the NaOH concentration (0.2 × 10–6 wt% to 7 wt%). The addition of less than 0.2 wt% of NaOH resulted in the formation of less than 4 mol% of sodium 4-hydroxyvalerate. A maximum amount of 21 mol% of 4-HVA was observed in a 7 wt% NaOH solution. The degree of decomposition after treatment was determined by NMR analysis. To verify the GVL stability under practical conditions, Betula pendula sawdust was fractionated in 50 wt% GVL with and without the addition of H2SO4 or NaOH at 180 °C and a treatment time of 120 min. The spent liquor was analyzed and a 4-HVA content of 5.6 mol% in a high acidic (20 kg H2SO4/t wood) and 6.0 mol% in an alkaline (192 kg NaOH/t wood) environment have been determined.