Excellent Low Temperature Research Articles

Low-temperature catalytic performance improvement of Ru/TiO2{001} for o-dichlorobenzene oxidation

Low-temperature catalytic performance improvement of Ru/TiO2{001} for o-dichlorobenzene oxidation

Synthesis and characterization of high-density biosynthetic fuels from myrtenal

Synthesis and characterization of high-density biosynthetic fuels from myrtenal

Excellent low temperature performance for modified asphalt by finely dispersed sidewall tire rubber

Low temperature performance of rubber asphalt in cold regions still has challenges for facing cracking. In this study, the modified asphalt by finely dispersed degraded sidewall tire rubber (STR) was prepared to study its low temperature performance by bending beam rheometer, differential scanning calorimetry, Fraass brittleness temperature and ductility. Results showed that low test temperature and Fraass brittleness temperature of STR-modified asphalt could be down to −24.0 °C, both of which were better than that of current crumb tire rubber modified asphalt. The ductility at temperature of 5 °C was 22.3 cm, which was higher than those of other tire section rubber modified asphalt, such as tread tire rubber modified asphalt (TTRMA, 19.8 cm) and bead tire rubber-modified asphalt (BTRMA, 15.6 cm). This was owing to that STR-modified asphalt had low glass transition temperature (Tg) of −33.1 °C, which was lower than those of TTRMA (−32.9 °C) and BTRMA (−31.2 °C). Modification mechanism proposed that flexible butadiene rubber (Tg of −110.0 °C) in STR strongly promoted the relaxation of rubber molecular segments through molecular orientation and conformation switching when suffering stress concentration. Accordingly, the STR-modified asphalt had excellent low temperature performance, and could be practically used for flexible pavement in cold region.

Zinc Single-Atom-Regulated Hard Carbons for High-Rate and Low-Temperature Sodium-Ion Batteries.

Hard carbons, as one of the most commercializable anode materials for sodium-ion batteries (SIBs), have to deal with the trade-off between the rate capability and specific capacity or initial Columbic efficiency (ICE), and the fast performance decline at low temperature (LT) remains poorly understood. Here, a comprehensive regulation on the interfacial/bulk electrochemistry of hard carbons through atomic Zn doping is reported, which demonstrates a record-high reversible capacity (546 mAh g-1 ), decent ICE (84%), remarkable rate capability (140 mAh g-1 @ 50 A g-1 ), and excellent LT capacity (443 mAh g-1 @ -40 °C), outperforming the state-of-the-art literature. This work reveals that the Zn doping can generally induce a local electric field to enable fast bulk Na+ transportation, and meanwhile catalyze the decomposition of NaPF6 to form a robust inorganic-rich solid-electrolyte interphase, which elaborates the underlying origin of the boosted electrochemical performance. Importantly, distinguished from room temperature, the intrinsic Na+ migration/desolvation ability of the electrolyte is disclosed to be the crucial rate-determining factors for the SIB performance at LT. This work provides a fundamental understanding on the charge-storage kinetics at varied temperatures.

Pt-stabilized electron-rich Ir structures for low temperature methane combustion with enhanced sulfur-resistance

Pt-stabilized electron-rich Ir structures for low temperature methane combustion with enhanced sulfur-resistance

Investigation on the technical performance and workability of hot-melting road marking materials using for the high-altitude area

Investigation on the technical performance and workability of hot-melting road marking materials using for the high-altitude area

A Li3PO4 coating strategy to enhance the Li-ion transport properties of Li2ZnTi3O8 anode material for Lithium-ion Battery

A Li3PO4 coating strategy to enhance the Li-ion transport properties of Li2ZnTi3O8 anode material for Lithium-ion Battery

Engineering of ZnO/rGO towards NO2 Gas Detection: Ratio Modulated Sensing Type and Heterojunction Determined Response.

Nanoscale heterostructured zinc oxide/reduced graphene oxide (ZnO/rGO) materials with p-n heterojunctions exhibit excellent low temperature NO2 gas sensing performance, but their doping ratio modulated sensing properties remain poorly understood. Herein, ZnO nanoparticles were loaded with 0.1~4% rGO by a facile hydrothermal method and evaluated as NO2 gas chemiresistor. We have the following key findings. First, ZnO/rGO manifests doping ratio-dependent sensing type switching. Increasing the rGO concentration changes the type of ZnO/rGO conductivity from n-type (<0.6% rGO) to mixed n/p -type (0.6~1.4% rGO) and finally to p-type (>1.4% rGO). Second, interestingly, different sensing regions exhibit different sensing characteristics. In the n-type NO2 gas sensing region, all the sensors exhibit the maximum gas response at the optimum working temperature. Among them, the sensor that shows the maximum gas response exhibits a minimum optimum working temperature. In the mixed n/p-type region, the material displays abnormal reversal from n- to p-type sensing transitions as a function of the doping ratio, NO2 concentration and working temperature. In the p-type gas sensing region, the response decreases with increasing rGO ratio and working temperature. Third, we derive a conduction path model that shows how the sensing type switches in ZnO/rGO. We also find that p-n heterojunction ratio (np-n/nrGO) plays a key role in the optimal response condition. The model is supported by UV-vis experimental data. The approach presented in this work can be extended to other p-n heterostructures and the insights will benefit the design of more efficient chemiresistive gas sensors.

Fabrication of high-performance CeO2–MnOx/TiO2/Ti monolithic catalysts for low-temperature and stable CO oxidation

The CeO2–MnOx/TiO2/Ti catalysts synthesized in this work show excellent low temperature CO oxidation performance and long-term stability.

High Dispersed Pd, Pt Supported on La, Ce-Alumina for Excellent Low Temperature Toluene Oxidation: Effect of Calcination Temperature and Ascorbic Acid Reduction

High Dispersed Pd, Pt Supported on La, Ce-Alumina for Excellent Low Temperature Toluene Oxidation: Effect of Calcination Temperature and Ascorbic Acid Reduction

Effect of bio-asphalt as additive on macro and micro properties of TLA modified asphalt and its modification mechanism

Effect of bio-asphalt as additive on macro and micro properties of TLA modified asphalt and its modification mechanism

Enhanced superhydrophobicity of electrospun carbon nanofiber membranes by hydrothermal growth of ZnO nanorods for oil–water separation

Enhanced superhydrophobicity of electrospun carbon nanofiber membranes by hydrothermal growth of ZnO nanorods for oil–water separation

Alkylation of Tetralin with Butene/Propylene Catalyzed by Ionic Liquid and Its Lubricating Properties

Alkyltetralins similar to naphthenic base oil were successfully synthesized by Friedel–Crafts alkylation of tetralin with short-chain α-olefins (C3/C4), where the applied chemical feedstock could be obtained from coal chemical industry with ease. The Et3NHCl-AlCl3 ionic liquid (IL) as catalyst exhibited excellent catalytic performance for alkylation of tetralin with n-butene or propylene. The reaction conditions were investigated in detail to achieve the high selectivity toward multi-alkyltetralins, and the selectivity for multi-alkyltetralins could reach as high as 90% with the complete conversion of tetralin. For comparison, three alkyltetralins with various side-chain alkyl groups and number of side-chains on tetralin were isolated, which behaved as lubricating base oils for investigation. The synthetic oils exhibited an excellent low temperature fluidity, and good potential for compatibility with additives. Di-propyltetralins (DPT) and di-butyltetralins (DBT) displayed the lower friction and wear values than mono-butyltetralins (MBT), which had comparable tribological properties to the commercial naphthenic base oil 4006 (N4006).

Enhanced low temperature catalytic activity for toluene oxidation over core-shell LaMnO3@α-MnO2 catalyst with oxygen vacancies

Engineering oxygen vacancies is an effective strategy to enhance the catalytic activity of MnO 2 based composite oxides in heterogenous reactions, such as volatile organic compounds (VOCs) oxidation reaction. Core-shell structure LaMnO 3 @α-MnO 2 catalysts were prepared by hydrothermal method via varying the concentrations of LaMnO 3 and used in toluene oxidation reaction. Irregular core-shell structure L@M-10 catalyst exhibits excellent low temperature catalytic activity and stability, achieving 100% toluene removal efficiency at 200 °C. The light-off temperature (T 50 ) and complete conversion temperature (T 90 ) are 235 and 271 °C even after five repetitive cycles, respectively. The interfacial effect of L@M-10 sample promotes the generation of oxygen vacancies, facilitating the formation of active oxygen species. A possible oxidation reaction mechanism of toluene over L@M-10 catalyst was proposed in combination with the in-situ DRIFTS results. Fast ring-opening reaction and quick transformation of carboxylate or anhydride species into final products CO 2 and H 2 O explains the superior catalytic property and stability of L@M-10 sample. This work highlights the effect of interface on the catalytic activity and stability of LaMnO 3 @α-MnO 2 catalyst towards toluene oxidation and can offer a new insight into the utilization of interfacial effect in thermocatalytic reactions. : The following figures are results of catalytic activity of different samples and simulation diagram of toluene oxidation over L@M-10 catalyst.

Enhancement of PdV/TiO2 catalyst for low temperature DCM catalytic removal and chlorine poisoning resistance by oxygen vacancy construction

• Abundant oxygen vacancy was formed in transformation process of part anatase TiO 2 to rutile phase. • Pd 0.12 V 4 /TiO 2 -Vo catalyst possessed rich acid site, higher O ads ratio and better oxygen mobility. • A better Cl resistance for Pd 0.12 V 4 /TiO 2 -Vo catalyst was presented. TiO 2 -Vo support with abundant oxygen vacancy was prepared by hydrothermal method, purchased TiO 2 -P for comparison, and Pd 0.12 V 4 /TiO 2 catalysts with different TiO 2 structures were prepared to investigate catalytic oxidation for dichloromethane (DCM). Pd 0.12 V 4 /TiO 2 -Vo catalyst showed excellent low temperature DCM removal efficiency, T 90 of which reduced to 290 ℃, and Cl resistance was maintained in 40 h. Abundant oxygen vacancy of TiO 2 -Vo was formed in transformation process of part anatase TiO 2 to rutile phase. The obtained Pd 0.12 V 4 /TiO 2 -Vo catalyst possessed rich acid sites, higher adsorbed oxygen (O ads ) ratio and better oxygen mobility, which inhibited loss of active components and improved DCM removal efficiency. DCM removal efficiency of Pd 0.12 V 4 /TiO 2 catalyst was reduced by HCl, while negative effect in the way of weakening competitive adsorption between HCl and DCM, that would be reduced by TiO 2 supports modification. The present work is favorable for further DCM removal catalyst anti-Cl poisoning modification and application in manufacture industry.

A Carboxylic Ester-Based Electrolyte with Additive to Improve Performance of Lithium Batteries at Ultra-Low Temperature

Lithium metal batteries (LMBs) are the promising battery system to push energy density to high level at low temperatures. In this work, the linear carboxylic esters methyl propionate (MP)-based electrolyte with 4 wt% fluorinated ethylene carbonate (FEC) is reported. The low melting point and viscosity of MP makes it the candidate solvent for the low temperature field. Assisted with FEC, the optimized electrolyte shows quite high ionic conductivity and better compatibility with separator and lithium metal anode, resulting in stable cycling performance at room temperature. Besides, it keeps liquid state at −70 °C and exhibits lower binding energy with lithium ion, enabling the Li/LiCoO2 batteries to cycle at −40 °C for 60 cycles. Apart from that, this battery can retain 88.6% discharge capacity at −70 °C of that at room temperature, reaching the highest discharge capacity retention at this ultra-low temperature to the best of our knowledge. This work demonstrates a simple but effective way to design the electrolytes with excellent low temperature performance.

Effects of substituting iron for aluminum on the low-temperature catalytic activity and sulfur resistance of hydrotalcite-derived LNT catalysts.

The storage and reduction of NOx on a series of Fe-modified hydrotalcite-based lean NOx trap catalysts were assessed, together with the product selectivity. The crystal structures and micromorphologies of these materials were characterized using X-ray diffraction and scanning electron microscopy, while in situ diffuse reflectance Fourier transform infrared spectroscopy was used to evaluate the evolution of transition state species. The introduction of Fe was found to improve the synergistic interaction between the Mg and Fe in the hydrotalcite structure, allowing these catalysts to work efficiently at low temperatures. In addition, both Pt/BaO/MgAlO and Pt/BaO/MgFeO catalysts exhibited better NOx adsorption and reduction performance compared with Pt/BaO/Al2O3. The superior performance of the former two materials was attributed to the enhanced adsorption of NOx in the form of nitrates and nitrites by Fe and Mg and to the ready decomposition of these nitrates at low temperatures. A Pt/BaO/MgFeO catalyst showed excellent low temperature activity and high selectivity for N2 together with superior sulfur resistance compared with Pt/BaO/Al2O3.

Ti3C2 MXene-derived Li4Ti5O12 nanoplates with in-situ formed carbon quantum dots for metal-ion battery anodes

Two-dimensional (2D) material Ti3C2 MXenes have recently been used in electrode composites for lithium-ion batteries (LIBs) for their excellent electrical conductivity and accordion-like nanosheet morphology. However, Ti3C2 has low specific capacity and fast degradation rate upon cycling after inevitably coupling with surface species during synthesis. In this work, Ti3C2 is used as Ti-source for Li4Ti5O12 (LTO) and C-source for carbon quantum dots (CQDs) in a one-step hydrothermal process. The resultant LTO product (M-LTO) inherits the nanosheet morphology of Ti3C2 with uniformly anchored CQDs. The highly electronic conductive CQDs optimize the transmission path of ions which reduces the diffusion barrier of ions, and they further increase the density of states of the material which effectively improving the conductivity of M-LTO. Remarkable electrochemical performances including high initial specific capacity, long lifetime and excellent low temperature capacity are demonstrated for this type of electrode in LIBs, sodium ion batteries (SIBs) and lithium-magnesium ion hybrid batteries (LMIHBs). This paper offers a new strategy to the rapidly expanding research on the application of transition metal MXenes in electrodes for metal-ion batteries.

Ultrahigh Low-Temperature Toughness of Polypropylene Composites with Low Ductile-Brittle Transition Temperature by Introducing Traces of Needlelike Wollastonite

In order to survive harsh settings, such as outer space, deep sea and high plains, needlelike wollastonite fibers (WF) were incorporated into polypropylene/ethylene octene block copolymer/β-nucleating agent (PP/OBC/β-NA) blends with the hope of tailoring the low-temperature toughness. The results revealed that WF showed very satisfactory toughening effects in the PP/OBC/β-NA/WF composites at low temperature (–20 °C). The impact strength of the WF-0.05 was as high as 32.1 kJ/m2 at −20 °C, which was 286.6% higher than that of the WF-0 sample, and even 832.6% higher than that of the pure PP sample. SEM characterization showed that by simultaneously adding WF and β-NAs, much coarse and tremendous plastic deformation appeared in the WF-0.05 after impacting. The low-temperature toughening mechanism is systematically discussed. The increase of β-crystallinity, caused by the synergy of β-nucleating agent and WF fillers, was mainly responsible for the enhancement of the impact strength of the composites with WF. On the other hand, when the transmitting of the stress, the overlapping of the stress and the hindering effect of WF on cracks occurred simultaneously; it resulted in the excellent low temperature toughness of the PP composites. Such outstanding-performance material with the advantages of facile processing and low cost is unprecedented. It shows a promising future application in many fields, especially aerospace, navigation, and the automotive industry.

Insights into the highly activity CuMgFe oxides for the selective catalytic reduction of NO by CO: Structure-activity relationships and K/SO2 poisoning mechanism

• CuMgFe composite oxides with flower-like morphology was prepared for CO-SCR of NO. • CuMgFe-500 exhibited 100% NO conversion at 225 °C with excellent H 2 O resistance. • The activity was related to surface oxygen vacancies and its superior redox ability. • The CO-SCR reaction mechanism was proposed based on in situ DRIFT spectra. • The main causes of K-poisoning and anti-SO 2 mechanisms were elucidated. The selective catalytic reduction of NO by CO is a promising technology for the simultaneous removal of both NO and CO pollution. Hence, a series of CuMgFe composite metal oxides with flower-like morphology was prepared by co-precipitation method for SCR of NO by CO. CuMgFe oxide calcined at 500 °C (CuMgFe-500) exhibited excellent low temperature activity. NO conversion reaches 100% at 225 °C, and it exhibits superior anti-H 2 O/SO 2 ability (250 °C). The excellent activity of CuMgFe-500 was associated with its abundance of surface oxygen vacancies and excellent redox performance. The reaction mechanism of CuMgFe-500 CO catalytic reduction of NO was investigated by in situ DRIFTS. The results show that monodentate nitrate and labile carbonate intermediate species are generated on the catalyst surface. Its reaction follows the E-R mechanism and the L-H mechanism. The introduction of K reduced the surface oxygen adsorption and redox properties of CuMgFe-500 catalyst, which were the main reason for the poor low-temperature activity of K-poisoned catalyst. In situ DRIFTS analysis showed that SO 2 hardly inhibits NO adsorption, which were the main reason for the excellent sulfur resistance of CuMgFe-500. This work provides new insights into the development and design of low-temperature CO-SCR catalysts.