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The scarcity and poor long-term stability of Pt has greatly hindered its commercial application as oxygen reduction reaction (ORR) catalyst. In this work, carbon-supported Pd9Au1 alloy particles with a Pd/Au molar ratio of 9:1 synthesized by using an ethylene glycol-based reduction method were used to catalyze ethanol oxidation to coat Pd9Au1 core with Pt atomic layers to synthesize Pd9Au1@Pt/C catalyst. Physical characterization shows that the as-synthesized Pd9Au1@Pt/C catalysts present a well-defined core-shell structure and the surface Pt layers can be well controlled by tuning the amount of Pt precursor added during synthesis. Electrochemical characterization shows that among the synthesized catalysts Pd9Au1@Pt2/C with 2 atomic Pt layers exhibits the best activity and excellent stability for ORR, as evidenced by its even increased half-wave potential after 10000 potential cycles between 0.6 and 1 V in O2-saturated 0.1 M HClO4 solution. This enhanced ORR activity and stability of Pd9Au1@Pt2/C catalyst can be attributed to the compressive strain and stabilizing effect of Pd9Au1 core on Pt shell.

NH3 decomposition over non-noble catalyst to generate COx-free H2 has attracted great attention in recent years. In this work, fumed SiO2-supported Ni, Co and Ni–Co bimetallic catalysts are synthesized by using a co-impregnation method and evaluated for NH3 decomposition, which shows that the bimetallic catalysts exhibit better catalytic activity than the monometallic ones. This enhanced activity observed on bimetallic catalyst can be largely attributed to the more appropriate catalyst metal-N binding energy resulting from the synergistic effect between Ni and Co in the formed Ni–Co alloy. Among the synthesized catalysts, Ni5Co5/SiO2 synthesized with the Ni/Co molar ratio of 5:5 achieves 76.8% NH3 conversion under a GHSV of 30,000 mL h−1 g−1cat at 550 °C and shows the best catalytic activity, which can be further improved by doping with K (78.1% NH3 conversion at 30,000 mL h−1 g−1cat), and the obtained Ni5Co5/SiO2–K also shows excellent catalytic stability.

The commonly used Pt/C catalyst has low durability for oxygen reduction reaction (ORR). In this work, CNT-supported TiO2 nanoparticles, which synergistically combines the merits of TiO2 (high stability and strong interactions with the supported Pt nanoparticles) and CNT (high specific surface area and large electrical conductivity), are prepared by a sol-gel process coupled with an annealing process and used as the support for Pt nanoparticles, which are anchored around TiO2 nanoparticles by a photodeposition technique. The as-synthesized Pt/TiO2@CNT catalyst exhibits a mass activity 5.3 times as large as that of the commercial Pt/C catalyst (0.358 A mgPt−1 vs. 0.067 A mgPt−1 at 0.9 V) and an excellent stability (no activity loss after 10000 potential cycles) for ORR, which can be mainly attributed to the lower oxygen adsorption energy of Pt, resulting from the strong metal-support interaction induced by the deposition of Pt nanoparticles around the well-dispersed TiO2 nanoparticles on CNT.

Among the Fischer-Tropsch synthesis (FTS) catalysts, Cobalt catalysts are currently attracting a lot of research interests due to their high activity and high selectivity. But the dispersion and reducibility of cobalt catalysts with moderate interaction between cobalt and support are still a challenge. A novel amino-ended hyperbranched polyamide (AEHPA) was used to modify SBA-15 and then was applied as support for obtaining cobalt catalyst (15Co/SBA-15-N). The catalysts were characterized by XRD, TEM, XPS and H2-TPR techniques. The results showed that AEHPA doped mesoporous SBA-15 caused the generation of N species in the SBA-15 pore channels. The N-Co bonds resulted in the formation of highly-dispersed cobalt nanoparticles with uniform sizes inside the ordered mesopores of support. AEHPA doping was an effective way to modify the surface properties of the SBA-15 for immobilizing cobalt nanoparticles. Compared with the conventional 15Co/SBA-15 catalyst without doping AEHPA, the AEHPA doped 15Co/SBA-15-N catalyst showed improved cobalt dispersion and stabilized cobalt location, which led to much better reaction stability as well as C5+ selectivity.

ZSM-5 seeds grafted mesoporous aluminosilicates with different morphologies (SZM-1 (two-dimensional (2D) structure), MZM-2 (three-dimensional (3D) structure), MZM-1 (mixture of 2D and 3D structure)) were synthesized by varying benzene addition amount. These composites were used as supports for Co (20 wt%) catalysts, which were prepared by simple incipient wetness impregnation method. Their catalytic performance was evaluated by Fischer–Tropsch synthesis (FTS) reaction. The supports and corresponding catalysts were characterized by N2 adsorption–desorption, XRD, TEM, H2-TPR, NH3-TPD techniques. 20Co/SZM-1 catalyst showed a highest FTS activity and best reaction stability, due to its higher cobalt dispersion, good cobalt reducibility and the confinement effect of two-dimensional structure. Compared to 20Co/SZM-1, 20Co/MZM-2 catalyst exhibited much higher selectivities to short-chain hydrocarbons and iso-paraffins, which may be attributed to the combination effects of its three-dimensional open pore structure and stronger acidity, leading to less diffusion limitation of hydrocarbon products and thus presenting a smaller chain-growth probability.

Nitrogen-doped carbon (N–C) materials are promising low-cost catalysts for oxygen reduction reaction (ORR). However, the commonly used route for N–C synthesis, viz., the high-temperature pyrolysis of N- and C-containing precursors, usually results in a great loss of N-containing species determining the ORR catalytic performance. Herein, porous N–C materials are synthesized by using g-C3N4 embedded in glucose-derived carbon as template and N source. The N–C sample synthesized at 900 °C with a mass ratio of glucose to g-C3N4 being 4:1 exhibits a positive half-wave potential (E1/2 = 0.823 V), good long-term stability and dominant 4 e− pathway for ORR in alkaline media, which can be attributed to its large specific surface area, high porosity, and large fraction of pyridinic and graphitic N. When a small amount of Fe is doped into the N–C sample, its ORR performance can be greatly improved and outperforms the commercial Pt/C catalyst in terms of ORR activity (E1/2 = 0.880 V), long-term stability and methanol tolerance. Notably, primary Zn-air batteries with N–C and Fe–N–C being the cathode catalysts exhibit peak power densities of 88 and 100 mW cm−2, respectively. This work offers a promising route for the synthesis of porous carbon-based materials highly efficient as ORR catalyst for Zn-air battery.

In this study, the mixed solvent of octanol (NOA) and methyl isobutyl ketone (MIBK) was used as extractant to purify wet process phosphoric acid from hydrochloric acid route. Densities and viscosities of leachate, extraction phase and raffinate phase were determined at 293–333 K, respectively. And the relation between density and temperature or phosphoric acid concentration can be expressed as a linear equation, with the maximum deviation of 0.0011 and 0.0027 g cm−3, respectively. Meanwhile, the viscosity of leachate, extraction phase and raffinate phase were measured since its importance on mass transfer occurred in the process of phosphoric acid extraction. And the relation between viscosity and temperature or phosphoric acid concentration can be summarized as a unitary quadratic equation, with the maximum deviation of 0.4489 and 0.1122 mPa·s, respectively. The results show that the densities and viscosities from experiment are generally in good agreement with calculated values from those equations obtained by regression analysis. The combined expanded uncertainty in the reported densities and viscosities are 0.3% and 5.5% of the measured values respectively, each with a coverage factor, k = 2.

Comb-shaped polysulfone anion exchange membranes (AEMs) containing various pendant alkyl side chains were synthesized and characterized. Ionic clusters aggregation is observed in transmission electron microscopy (TEM) image and small-angle X-ray scattering (SAXS). The comb-shaped quaternized ammonium polysulfone (Cx-QAPSU) membranes show enhanced dimensional stability and ultra-low membrane area resistance (Rm). Notably, the C16-QAPSU with 16 carbon atoms has the best hydrophilic-hydrophobic phase separation structure and lowest Rm of 2.5 Ω cm2 despite low ion exchange capacity (IEC) of 1.55 mmol/g and swelling ratio of 5.3%. Moreover, comb-shaped AEMs show much higher tensile strength (TS) compared to QAPSU membrane under the same IEC level. The C16-QAPSU with lowest Rm of 2.5 Ω cm2 exhibits the highest TS of 16.7 MPa. These results indicate that the long alkyl side chains especially the length of the pendant side chain of Cx-QAPSU up to C16 achieve an electrochemical-mechanical balance of AEMs. In electro-electrodialysis systems, the comb-shaped AEMs exhibit higher purification efficiency of wet phosphoric acid than non-comb-shaped AEMs.

Pyrolyzing precursors containing iron, nitrogen and carbon elements is a commonly used process for synthesizing Fe N C catalysts for oxygen reduction reaction (ORR). Generally, aggregation of iron-based species is prone to occur because of a lack of chemical bonds between iron-based species and carbon matrix and synthesizing highly porous Fe N C catalysts is difficult because carbon skeleton is prone to collapse during pyrolysis. Herein, highly porous Fe N C catalysts with fine iron-based species are synthesized by selecting glucose as carbon source, FeCl3 as iron source, and urea-derived g-C3N4 as nitrogen source, iron anchoring and stabilizing species, and pore-forming template. The multi-role g-C3N4-derived catalyst synthesized at 1100 °C (Fe N C 1100) has fine iron-based species, large specific surface area (737 m2 g−1), and extremely high pore volume (2.66 cm3 g−1). Accordingly, Fe N C 1100 shows a larger half-wave potential (E1/2 = 0.894 V), a higher stability (ΔE1/2 = 6 mV) after 10,000 potential cycles in alkaline media, and a higher peak power density (P = 152 mW cm−2) when employed as ORR catalyst of zinc-air battery, which are all superior to those of the commercial Pt/C catalyst (E1/2 = 0.864 V, ΔE1/2 = 30 mV, P = 134 mW cm−2). The present work brings a new method for synthesizing highly porous Fe N C catalysts decorated with fine active sites for ORR.

Zn and N co-doped carbon (Zn-N-C) shows encouraging catalytic stability for oxygen reduction reaction (ORR) because of the fulfilled d orbital of Zn, but its catalytic activity is not satisfactory. Herein, hierarchically porous Zn, S and N co-doped carbon (Zn-S-N-C) with large specific surface area (2433 m2 g−1) and pore volume (3.007 cm3 g−1) is synthesized by using NaCl/ZnCl2-assisted pyrolysis of sucrose and thiourea. The Zn-S-N-C catalyst exhibits superior ORR activity with half-wave potentials (E1/2) up to 0.774 V in 0.1 M HClO4 and 0.894 V in 0.1 M KOH, good ORR stability with 19- and 4-mV loss in E1/2 values after 10,000 potential cycles in 0.1 M HClO4 and 0.1 M KOH, respectively, and excellent methanol tolerance. The good ORR performance of Zn-S-N-C can be attributed to its enhanced intrinsic ORR activity resulting from the formation of S, N doped carbon and ZnS in Zn-S-N-C, its hierarchically porous structure resulting from the pore-forming roles played by ZnCl2, NaCl and thiourea, and its improved graphitization degree resulting from the added ZnCl2 during Zn-S-N-C synthesis. This work will provide a novel strategy for the synthesis of hierarchically porous Zn, S and N co-doped carbon materials for ORR.

A series of quaternary ammonium polysulfone (QAPSU) anion exchange membranes used the chlorotrimethylsilane instead of toxic chloromethyl methyl ether and quaternized-functionalized by trimethylamine ethanol solution were prepared. The effect of chloromethylation reaction time on membrane morphologies and physiochemical properties such as ion exchange capacity, water swelling, and membrane area resistance, mechanical and thermal stabilities was investigated. When being applied in electro-electrodialysis (EED) for purifying phosphoric acid solution, the QAPSU membranes exhibit high purification efficiency, especially all the metal ions (Fe, Mg, Ca) removal rates reach over 60%, which suggests that the QAPSU membranes have a high potential for EED application.

In the present work, experiments have been performed for leaching potassium from phosphorus-potassium associated ore in hydrochloric acid/fluorite system. Surfactant or phosphoric acid extractant was added into the leaching system to enhance the leaching efficiency. The results show that alcohol chain length has great influence on potassium leaching and among the additives investigated, lauryl alcohol exhibits the largest promoting effect on potassium leaching and the leaching fraction of potassium can be increased from 89.5% to 97.8% with the addition of 1 mL of lauryl alcohol into 80 mL of leaching solution. The enhanced leaching observed in the presence of lauryl alcohol can be attributed to the hydrophobicity mechanism. The kinetic analysis shows that there are two distinct stages in the leaching process and the kinetics of both stages follows the classical shrinking core model with chemical reaction being the rate-controlling step.

Fenton's reagent, ultrasound, and the combination of Fenton's reagent and ultrasound were used to pretreat rice straw (RS) to increase its enzymatic digestibility for saccharification. The characterization shows that compared with ultrasound, Fenton's reagent pretreatment was more efficient in increasing the specific surface area and decreasing the degree of polymerization (DP) of RS. The enzymatic hydrolysis results showed that the RS pretreated by ultrasound-assisted Fenton's reagent (U/F-RS), which exhibited the largest specific surface area and the lowest DP value, had the highest enzymatic activity, and the amount of reducing sugar released from U/F-RS at 48h of enzymatic saccharification is about 4 times as large as that from raw RS and 1.5 times as large as that from Fenton's reagent pretreated RS. The ultrasound-assisted Fenton process provides a reliable and effective method for RS pretreatment.

A novel SBA-15 (2.5N-SBA-15) with pores penetrating into the silica walls has been synthesized with amino-ended hyperbranched polyamide (AEHPA) and P123 as co-templates. This novel template method successfully imprints mesoporous cavities into the silica structure. The obtained composites are used as a Co (15 wt%) catalyst support for Fischer–Tropsch Synthesis (FTS). The catalytic activity and product selectivity are significantly influenced by the support structure. Compared with the conventional 15Co/SBA-15 catalyst, the 15Co/2.5N-SBA-15 catalyst with a penetrating pore structure shows improved reducibility of cobalt species, leading to better catalytic properties with respect to CO activity and C5+ selectivity during the FTS reaction.

TiO2-modified nitrogen-doped carbon (TiO2-NC), prepared by a polymerization-pyrolysis process, is used to support the Pd catalyst for ethanol oxidation reaction (EOR) in alkaline media. X-ray photoelectron spectroscopy characterization indicates that the incorporation of TiO2 and nitrogen into the carbon matrix could improve the percentage of Pd0 in Pd/TiO2-NC catalyst. Electrochemical characterization shows that the Pd/TiO2-NC catalyst presents higher electrocatalytic activity and stability for EOR than the nitrogen-doped carbon-supported Pd (Pd/NC) catalyst and the carbon black-supported Pd (Pd/CB) catalyst, which can be mainly attributed to the high percentage of Pd0 in Pd/TiO2-NC catalyst (65%) than those in Pd/NC (48%) and Pd/CB (31%) catalysts. The results indicate that the Pd/TiO2-NC catalyst holds great potential as high-performance anode catalyst for direct ethanol fuel cells.

A ZIF-derived Fe–Zn–N–C catalyst with sufficient exposure of bimetallic active sites and well-balanced micro/mesopores is synthesized by a two-stage pyrolysis process and exhibits superior oxygen reduction activity with high half-wave potentials of up to 0.819 V in 0.1 M HClO4 and 0.918 V in 0.1 M KOH.

Dihydroxylammonium5,5′-bistetrazole-1,1′-diolate (TKX-50) is considered as one of the new ionic energetic materials. In this study, we employed density functional theory (DFT) method to calculate the reaction path of TKX-50 and search its optimized configurations of reactants, reactant complexes (RCs), transition states (TSs), product complexes (PCs), and products. We proposed 10 simple reactions in the reaction path, and determined their transition states. Among these TSs, six of them have lower energies than those of reactants. The equilibrium constants, which indicate the limitation of reactions, were computed from the difference of Gibbs free energy with temperature change. Based on the proposed reaction path, the reaction mechanism of TKX-50 was provided.

In this study, the combined use of Fenton reagent and ultrasound to the pretreatment of microcrystalline cellulose (MCC) for subsequent enzyme hydrolysis was investigated. The morphological analysis showed that the aspect ratio of MCC was greatly reduced after pretreatment. The X-ray diffraction (XRD) and degree of polymerization (DP) analyses showed that Fenton reagent was more efficient in decreasing the crystallinity of MCC while ultrasound was more efficient in decreasing the DP of MCC. The combination of Fenton reaction and ultrasound, which produced the lowest crystallinity (84.8 ± 0.2%) and DP (124.7 ± 0.6) of MCC and the highest yield of reducing sugar (22.9 ± 0.3 g/100 g), provides a promising pretreatment process for MCC depolymerization.

ZnO materials with a range of different morphologies have been synthesized via a simple solvothermal method in dimethylacetamide (DMAc) media. DMAc was used as the base source and solvent in such solvothermal syntheses for the first time. The effect of the DMAc content in the solvothermal process on nucleation, growth, and the final morphology of the ZnO nanostructures was investigated. XRD results revealed that single-phase ZnO with the wurtzite crystal structure was obtained for different DMAc contents in solution. X-ray photoelectron spectroscopy confirmed high purity of the as-prepared ZnO crystals. SEM imaging showed that ZnO with spherical shapes, dumbbell, and rod-like were synthesized by controlling DMAc content. In addition, vibrational properties of ZnO crystals with different morphologies were investigated by Raman spectroscopy. The optical properties of the as-prepared ZnO materials were investigated by UV–vis absorption and room temperature photoluminescence. The possible mechanism was also proposed to account for the growth of the ZnO crystals in the DMAc solvent.

ZnO crystals have been prepared via a simple aqueous solution route using zinc acetate-hexamethylenetetramine (HMTA) solution. To understand the role of HMTA in the formation processes of ZnO crystals, concentration measurements of Zn(II) remaining in the solution as well as SEM and XRD analyzes of the solid product have been made at regular intervals. The results demonstrated that the HMTA concentration has determinative effects on the growth rate of obtained ZnO products by controlling the composition of zinc complex species and mediating the transformation rate of building blocks. XRD results revealed the single phase nature with the wurtzite structure of the as prepared ZnO rods. X-ray photoelectron spectroscopy confirmed high purity of the ZnO rods. By varying the concentration of HMTA in the solution, the average size of rods was varied from 5 μm to 10 μm. Photoluminescence spectra indicated that the photoluminescent intensity of the emission peak at 380 nm increase to different degree with increasing HMTA concentration. These results revealed that the concentration of HMTA plays a vital role to control the properties of ZnO crystals.

A novel worm-like mesoporous silica (denoted as HECMS) was prepared using the sol–gel method employing hydroxyethyl cellulose (HEC) as a template and sodium silicate nonahydrate as the silica source. Then, Cu and Ce doped mesoporous silica (Cu-HECMS/Ce-HECMS) were prepared using the sol–gel method in one-pot condensation. The obtained materials were characterized using X-ray diffraction, N2 adsorption-desorption, Fourier transform infrared spectroscopy and transmission electron microscopy. The BET specific surface area, pore volume and average pore size of HECMS were found to be 344.92 m2/g, 0.56 cm3/g and 5.85 nm, respectively. After the metal incorporation, the Cu-HECMS/Ce-HECMS maintained the worm-like mesoporous structure. HECMS, Cu-HECMS and Ce-HECMS were evaluated as adsorbents for the removal of methylene blue (MB) from aqueous solutions. The isotherms and kinetics corresponded to Freundlich isotherm and pseudo-second-order kinetic model, respectively. The adsorption capacity of Ce-HECMS was found to be 349.15 mg/g, while that of Cu-HECMS was 284.60 mg/g. In comparison, the corresponding adsorption capacity of HECMS was 282.08 mg/g.

Three kinds of novel environmentally benign and high-efficiency crude oil demulsifiers were prepared using methoxy polyethylene glycol (MPEG) to modify alkylated carboxymethyl chitosan (ACMC). Structures of the demulsifiers were confirmed using FT-IR and 1H NMR, and the relationship between surface tension and concentration was tested. Demulsification performance was investigated using the bottle test method with oil-in-water (O/W) emulsions that were prepared in lab conditions. The demulsification efficiency was as high as 79.1 %-84.9 %, and the possible mechanism of the demulsification process is discussed. Results show that MPEG-grafted ACMC (MPEG-ACMC) has a promising application as a demulsifier for dealing with emulsified O/W crude oil.

TKX-50 (dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate) has high energy storage, high detonation speed, low sensitivity and low toxicity. The addition of polymer binders can provide better flexibility for TKX-50 to improve safety when they are subjected to external mechanical stimuli. In this work, four polymer binders, i.e. glycidyl azide polymer (GAP), polyglycidyl nitrate (PGN), polyethylene glycol (PEG) and polytetrahydrofuran (poly-THF), are added to TKX-50 with a mass fraction from 1% to 12%. Matrix notation calculations showed that the elastic moduli of nanocomposites TKX-50/polymers reduced with the increase of the polymer concentration. The microscopic behavior of deformation of TKX-50/polymers were studied using non-equilibrium molecular dynamics (NEMD) simulations. Dependence of tensile strength and Young’s modulus on the mass fractions and structure of polymer binders was investigated. It is found that the GAP and PGN self-crimp on the surface of TKX-50, while PEG and poly-THF are extended on the surface of TKX-50. Our results showed that polymer binders can improve the mechanical properties of TKX-50 with an order of poly-THF ≈ PEG > PGN > GAP.

Carbon nanotubes (CNTs) have been considered as the attractively multifunctional nanomaterials for high conductivity and high strength, but it is still a challenge to prepare CNTs with high dispersion and their nanocomposites with simultaneous high strength and longation. Here, we used thiol-ended hyperbranched polymers to functionalize CNTs and obtain thiol-functionalized CNTs with excellent dispersion and good compatibility with epoxy resins matrix. The grafted thiol-ended hyperbranched polymers can supply a bridging function between epoxy resins and the CNTs to promote their interaction. The thermal conductivity, elongation, tensile, flexural and impact strengthes of thiol-functionalized CNTs/epoxy nanocomposites could be improved simultaneously by 23.33%, 37.46%, 60.74%, 26.72% and 86.71%, respectively. A reinforcing mechanism was supposed and substantiated by combining SEM, TEM, XPS and Raman techniques. The flexible and ellipsoidal hyperbranched polymers chains grafted on CNTs deform and transfer the load to increase mechanical strength and elongation. An efficient and environmentally-friendly route is introduced to functionalize CNTs and fabricate simultaneous high strength and high elongation CNTs/epoxy nanocomposites.

Carbon nanotubes (CNTs) have attracted increasingly interest in preparing CNTs/epoxy nanocomposites for improving thermal and mechanical properties. The well distribution of prime CNTs in epoxy matrix is still a challenge due to the strong interaction among nanotubes and property of self-aggregation. Here, we report a highly efficient approach to functionalize prime CNTs by a thiol-ene click reaction between double bonds of CNTs and thiol groups of mercaptans, and the resulted in thiol-functionalized CNTs with different chemical chains show well dispersion in ethyl acetate and epoxy. The thiol-functionalized CNTs show a positive effect on reinforcing and toughening diglycidyl ether of bisphenol-A (DGEBA). With an increase in the thiol-functionalized CNTs content, the mechanical and thermal properties of the CNTs/DGEBA nanocomposites, including tensile, flexural and impact strengths, and thermal conductivity, increase first and then decrease. The maximum improvements on the tensile, flexural, impact strengths and thermal conductive were 43.75%, 25.11%, 196.44% and 33.81%, respectively. These grafted mercaptans chains play a bridging action between CNTs and epoxy matrix to supply a strong interaction, substantiated by their good rheological property and ductile SEM micrographs. Both the simple method of thiol-functionalized CNTs and preparation of CNTs/DGEBA nanocomposites will supply dependable data for wide application of CNTs.