Journal of Materials Chemistry A
·
2016
·Vol. 5
·期 1
·266-274
·
IF 8.262
Man Huang,Kan Mi,Junhao Zhang,Huili Liu,Tingting Yu,Aihua Yuan,Qinghong Kong,Shenglin Xiong
To tackle the issue of the low specific capacity (372 mA h g−1) of graphite as the anode material for lithium-ion batteries (LIBs), an effective and controllable strategy was developed to construct porous bimetallic Co/Zn embedded N-doped carbon (Co–Zn/N–C) polyhedral nanocages via annealing a ZIF-8@ZIF-67 precursor at 800 °C under Ar atmosphere. The results clearly displayed that metallic Co and Zn particles are uniformly dispersed in the carbon matrix. Porous Co–Zn/N–C polyhedral nanocages have a large specific surface area of 349.12 m2 g−1 and contain plenty of micropores and mesopores, which benefit from the carbonization of organic ligands and the catalytic effect of cobalt in the calcination process. As anodes for LIBs, the porous Co–Zn/N–C polyhedral nanocages showed an initial discharge capacity of 809 mA h g−1 and a capacity retention of 702 mA h g−1 after 400 cycles at a current density of 0.2 A g−1. Furthermore, a reversible capacity of 444 mA h g−1 was obtained at a much higher current density of 2 A g−1. The improved electrochemical performance was attributed to the synergistic effect of Zn and Co, the unique porous hollow structure as well as N doping, which relieved the impact of volume changes, maintained perfect electrical conductivity throughout the electrode and enhanced the electrochemical activities of lithium storage.
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2017
·
IF 3.091
Bin Chen,Feng Xin,Xiaofei Song,Xingang Li,Muhammad Zeshan Azam
CO2 capture based on hydrate formation is intensified by an oil-in-water phase-change slurry (PCS) in which the n-tetradecane particles are taken as nucleation centers and are used to directly remove the hydration heat through their solid-to-liquid phase change. In this study, experiments on hydration were conducted at a temperature of 277.6 K and under isobaric pressures in the range of 2.1–2.4 MPa. All measurements were performed at a stirring speed of 450 rpm in PCSs of 25–45 wt % n-tetradecane. Two kinetics models, transport and reversible hydration, were established to regress and analyze the experimental data from the isothermal hydration of CO2 in a semibatch hydrator. For each model, the effects of pressure and PCS composition were examined in detail. As the experimental results show, the induction time before hydration initiated was less than 1 min for all runs, and the duration of the entire hydration process was approximately 13–15 min for each measurement. Furthermore, the average hydration rate reached 197 mol m–3 min–1 at 2.3 MPa in 45 wt % oil-in-water PCS, which demonstrates that the presence of n-tetradecane particles contributes significantly to the enhancement of hydrate formation rate. As the modeling results show, the parameters of the two models were determined by correlating the experimental data, and the interpretations of the measurements by the two models are satisfactory.
✓ 已验证
产品关联
DOI
高影响因子
TENSIDE SURFACTANTS DETERGENTS
·
2017
·Vol. 54
·期 1
·54-63
·
IF 0.869
Xu Li,Lan Wu,Qiong Tang,Jinxiang Dong
Glycerol, derived from biodiesel production, is a renewable feedstock for the production of value-added chemicals. Herein, we report an investigation of the acetalization of glycerol with n -octanal by homogeneous acid catalysis in the absence of a solvent, using p -dodecylbenzenesulfonic acid, p -toluenesulfonic acid, and sulfuric acid, respectively, as catalysts. p -Dodecylbenzenesulfonic acid, a surfactant-type Brønsted acid, proved to be an excellent catalyst capable of efficiently promoting the reaction under solvent-free conditions, and the yields of glycerol acetals reached 99% under the optimal conditions. The distribution of five- and six-membered cyclic acetal regioisomers varied depending on the reaction time and temperature. Moreover, the amphiphilic properties of the products, with different ratios of five- to six-membered cyclic acetals, have been evaluated by surface tension measurements.
✓ 已验证
产品关联
DOI
高影响因子
Heliyon
·
2024
·
IF 3.4
Jun Dong,Qiqi Jiao,Hao Wang,Hong Wang,Yi-ke Ren
The shortcomings of precious metal based catalysts have limited the development of novel energies. So, developing low-cost and high performance transition metal based catalysts is one of the most feasible way to substitute the precious metal based catalysts. In all of the developed catalysts for oxygen reduction reactions (ORR), the iron-based nitrogen doped carbon nanotube (N-CNT) show great promise. In this paper, N-CNT with Fe 3 C encapsulated based catalysts (Fe 3 C@N-CNT) were synthesized. The encapsulation structure of Fe 3 C@N-CNT was confirmed by HAADF-STEM, XANES, XPS, XRD, SEM and other methods. XANES tests show that the doped nitrogen of Fe 3 C changed the length of Fe-C bond and furtherly influenced the electron transfer between encapsulated Fe 3 C and outer layer N-CNT. Electrochemical tests showed that the half-wave potential and onset potential ORR of 750 °C calcined Fe 3 C@N-CNT were 90 mV higher than that of 20 wt% Pt/C. The additional electric field between Fe 3 C and N-CNT modulated the C-N bond of surface N-CNT and enhanced the catalytic performance for ORR. This paper reveal that constructing encapsulated additional electron providing center is an effective way to design high performance catalysts.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2024
·
IF 6.3
Xi Zhou,Quanzhen Liu,Xueman Chen,Ning Zhou,Guoguang Wei,Feifei Chen,Alei Zhang,Kequan Chen
In this study, we present an efficient and green extraction-pretreatment integrated approach for enhancing enzymatic conversion of chitinous wastes into N -acetyl- d -glucosamine (GlcNAc). Firstly, the enzyme cocktail containing a chitinase Cm Chi1 and a N-acetyl glucosaminase Cm NAGase were constructed for hydrolyzing chitin into sole GlcNAc. Secondly, deep eutectic solvent (DES), consisting of choline chloride and glycollic acid was used to treat chitinous wastes. Under optimal conditions, chitin yield reach to 72 % with a purity of 98 %. Fourier-transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction analysis revealed that the crystallinity and thermal stability of the obtained chitin decreased upon DES treatment without alteration of the chemical structure or deacetylation. Finally, the concentration of GlcNAc was increased 2–6 folds by enzymatic hydrolysis of DES-treated chitinous wastes (including shrimp shell, crab shell, ganoderma spores wall, and mycelium). The process provides a promising strategy for degrading chitinous wastes to produce high valued GlcNAc.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2024
·
IF 5.7
Jiao Li,Ruiyang Li,Na Shang,Yan Men,Yi Cai,Yan Zeng,Weidong Liu,Jiangang Yang,Yuanxia Sun
The addition of the O-linked N-acetylglucosamine (O-GlcNAc) is a significant modification for active molecules, such as proteins, carbohydrates, and natural products. However, the synthesis of terpenoid glycoside derivatives decorated with GlcNAc remains a challenging task due to the absence of glycosyltransferases, key enzymes for catalyzing the transfer of GlcNAc to terpenoids. In this study, we demonstrated that the enzyme mutant UGT74AC1T79Y/L48M/R28H/L109I/S15A/M76L/H47R efficiently transferred GlcNAc from uridine diphosphate (UDP)-GlcNAc to a variety of terpenoids. This powerful enzyme was employed to synthesize GlcNAc-decorated derivatives of terpenoids, including mogrol, steviol, andrographolide, protopanaxadiol, glycyrrhetinic acid, ursolic acid, and betulinic acid for the first time. To unravel the mechanism of UDP-GlcNAc recognition, we determined the X-ray crystal structure of the inactivated mutant UGT74AC1His18A/Asp111A in complex with UDP-GlcNAc at a resolution of 1.66 Å. Through molecular dynamic simulation and activity analysis, we revealed the molecular mechanism and catalytically important amino acids directly involved in the recognition of UDP-GlcNAc. Overall, this study not only provided a potent biocatalyst capable of glycodiversifying natural products but also elucidated the structural basis for UDP-GlcNAc recognition by glycosyltransferases.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advances in Natural Sciences-Nanoscience and Nanotechnology
·
2024
·Vol. 15
·期 1
·015008
·
IF 1.7
Tai Thien Huynh,Quyen Huynh,Ngoc-Han T Huynh,Hau Quoc Pham
In this work, we prepared an Ir,N-doped TiO2 nanomaterial via a facile HNO3-assisted hydrothermal process that was used as an advanced support for nano-sized Pt nanoparticles (NPs) for the formic acid oxidation reaction (FAOR). The physical and electrochemical behaviours of the as-made Pt/Ir,N-doped TiO2 catalyst were systemically investigated through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscopes coupled with energy dispersive X-ray analysis (FE-SEM/EDX mapping), transmission electron microscopy (TEM), linear sweep voltammetry (LSV), Tafel slope, CO-stripping, and chronoamperometric (CA) test. The Pt NPs (ca. 3 nm) were anchored on the Ir,N-doped TiO2 support, being formed by a mixture of rutile and brookite with a particle size of several ten nanometers. Due to the small size and uniform distribution of Pt NPs, the Pt/Ir,N-doped TiO2 catalyst had an electrochemical surface area of 79.88 m2 g−1, which was greater than that of the commercial Pt/C (77.63 m2 g−1). In terms of the FAOR, the Pt/Ir,N-doped TiO2 catalyst showed a negative FAOR onset potential, high current density (11.85 mA cm−2), and superior CO-tolerance compared to the commercially available catalyst. Also, the as-made catalyst possessed high electrochemical durability after 3600 s for testing. The enhanced FAOR efficiency was assigned to the formation of a dual-doping effect and strong interplay between Pt and TiO2-based support, which not only improved the electron transfer but also weakened the adsorption of carbonaceous species, thereby boosting the reaction kinetics. This study could open up a facile but effective strategy to promote particular electrochemical applications.
✓ 已验证
产品关联
DOI
高影响因子
PHYSICA B-CONDENSED MATTER
·
2024
·
IF 2.8
MeiGe Ding,XiHao Gao,Yongchen Sui,Zhenyu Yuan
This study designs to investigate a high-performance n-butanol gas sensor with a porous morphology. Porous ZnO flakes modified with Ag particles are prepared in two steps using hydrothermal and precipitation methods. Morphological analysis of the samples shows that the ZnO flakes were covered with mesopores with high porosity, and their edge lengths ranged from 3 μm to 6 μm, with a minimum thickness of 11.3 nm. Through rigorous gas sensing testing, we find that the optimal mass percentage Ag-ZnO sensor provided significantly better sensing behavior, with a 100.8 response for 100 ppm n-butanol, compared to 14.5 for the pure ZnO sensor, a 5.95-fold improvement. In addition, the sensor's optimal operating temperature is reduced from 290 °C to 190 °C, increasing its adaptability and versatility in practical applications. In subsequent tests, it is found that this Ag-ZnO sensor not only shows excellent selectivity to n-butanol but also favorable stability, with no significant degradation during 30 days of continuous testing. The experimental analysis shows that the formation of porous flake structure and the modification of Ag particles are effective approaches to improve the ZnO gas sensor.
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2024
·
IF 2.3
Yang Zimin,Feng Lianggang,Pang Yongyu,Chai Guoliang
The ever-growing demand for hydrogen peroxide (H 2 O 2 ) makes large-scale production via environmentally-friendly strategies necessary. The electrochemical oxygen reduction reaction stands out as an efficient and green approach for H 2 O 2 production. Here, nitrogen-doped mesoporous carbon materials (NMCM) with a hollow semispherical morphology are synthesized for H 2 O 2 generation, which exhibit remarkable electrocatalytic stability, selectivity (94.5%), and onset potential (~ 0.6 V) toward the H 2 O 2 formation in neutral environment. The distinct H 2 O 2 production performance of NMCM can be attributed to synergistic effect of two factors, that is, the pyrrolic N to optimize the work function and the hollow semispherical morphology to facilitate mass transfer and expose abundant electrocatalytic active sites. This work offers a facile way to prepare metal-free electrocatalysts for realizing high-performance H 2 O 2 production in neutral solutions. Graphical Abstract Nitrogen-doped mesoporous carbon materials with a hollow semispherical morphology and high pyrrolic N contents are synthesized for efficient H 2 O 2 production.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2024
·Vol. 26
·期 5
·1-14
·
IF 2.1
Zhu Zijian,Li Yang,Li Xiaofei,Qiu Huiming,Fang Lei,Zheng Lingcheng,Gao Juan,Zhu Guang
Oxygen reduction reaction (ORR) is an important reaction process that occurs at the cathode of zinc-air batteries. An efficient reaction process is conducive to further research on sustainable energy devices. In order to improve the reaction speed, the ORR electrocatalyst containing uniform Fe–N-C sites in a porous carbon network similar to the shape of moth-eaten rotten wood was prepared using water hyacinth with a thin-layer structure inside as a template. Water hyacinth, plays a variety of synthetic functions in the construction of nanocatalysts, not only has a good enrichment effect on metal elements, but also is rich in N element. The doped Fe elements combine with the carbon and N elements of water hyacinth to form Fe–N-C active sites. The half-wave potential of SHL-Fe-HMNC is raised to 0.881 V (0.838 V for commercial 20wt% Pt/C) compared to the reversible hydrogen electrode (RHE). The power density of the liquid battery prepared based on SHL-Fe-HMNC reaches 110 mW·cm −2 (90 mW·cm −2 for 20 wt% Pt/C). Furthermore, the cycle time of ZABs exceeds 200 h. The flexible battery based on SHL-Fe-HMNC has a cycle stability of more than 10 h at a current of 10 mA·cm −2 , and the open circuit voltage (OCV) reaches 1.511 V. Graphical Abstract
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2024
·
IF 5.2
Peng Bai,Yicheng Zhao,Yongdan Li
Photocatalytic N -formylation of amines with CO 2 is a promising strategy to convert CO 2 into value-added chemicals sustainably. In this work, Pd-Bi bimetallic modified ZnO enriched in oxygen vacancies is constructed for photocatalytic CO 2 formylation of benzylamine at room temperature without any reductants. The Pd and Bi sites reduce the band gap energy of ZnO, promote the separation of the photogenerated charge carriers and enhance the adsorption capacity of CO 2 . The yield of N -benzylformamide reaches 31.7 mmol g −1 with a selectivity of 85.3 % after 3-hour radiation in N , N -dimethylformamide (DMF) solvent. The aldehyde group involved in the formylation of benzylamine is derived from the decomposition of DMF, which is regenerated with the aldehyde group coming from the reduction of CO 2 . The decomposition-regeneration cycle of DMF solvent enlarges the reaction region, which is beneficial to the activity and selectivity of the formylation process. The synergistic photocatalytic system shows a good universality. This study provides a new approach to high-efficiency CO 2 utilization and formamide production.
✓ 已验证
产品关联
DOI
高影响因子
BIOTECHNOLOGY AND BIOENGINEERING
·
2024
·
IF 3.5
Wentao Yang,Xiao Chen,Li Pang,Hong Tian,Liang Yang,Bo Xia
Glucosamine (GlcN) is a widely utilized amino monosaccharide. It is traditionally synthesized from N -acetylglucosamine (GlcNAc) via chemical processes that pose environmental threats. In pursuit of a greener alternative, our investigation explored biocatalysis with a Pantoea dispersa derived deacetylase (Pd-nagA), showcasing its efficacy as a catalyst in GlcN production. As a result, this work provides a comprehensive characterization of Pd-nagA, scrutinizes its enzymatic behavior, and delves into the deacetylation mechanism in detail. Heterologous expression methods were utilized for the production and isolation of Pd-nagA, followed by a kinetic evaluation highlighting its enzymatic activity. The complex interactions between the enzyme and its substrate were investigated by integrating classical molecular dynamics, quantum mechanics/molecular mechanics simulations, funnel metadynamics, and on-the-fly probability enhanced sampling techniques, thereby elucidating the precise deacetylation pathway. Rigorous computational analysis results demonstrated that Pd-nagA exhibited promising specificity and efficiency for GlcNAc with a high turnover rate. The catalytic residues central to the reaction were identified, and the underlying quantum reaction mechanism was detailed. Our findings suggest an approach to GlcN production using eco-friendly biocatalysis, positioning Pd-nagA at the forefront of industrial application not only because of its remarkable catalytic capabilities but also due to its potential for enzyme optimization.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）