JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Sensen Yu,Jie Xu,Qingyong Wang,Yongjin Zou,Cuili Xiang,Fen Xu,Lixian Sun,Menghe Jiang,Zhicong Hu,Xuebu Hu
Slow water dissociation (the Volmer step) is the rate-limiting step in the alkaline hydrogen evolution reaction (HER), which limits the efficient industrial production of clean hydrogen. In this study, a novel hollow oxygen-rich vacancy polymetallic nitride , Co 2 NiMo-N, is proposed as a HER catalyst. The synergistic interaction between Co, Ni, and Mo promotes the Mo elemental activity and increases the conductivity of the material. The porous hollow structure exposes enough active sites to facilitate electron transfer . Numerous oxygen vacancies (O V s) reduced the Gibbs free energy (ΔG H* ) of H* adsorption and promoted the Volmer step, thus improving the electrocatalytic hydrogen evolution performance of the material. The Co 2 NiMo-N catalyst exhibited excellent HER activity with a low overpotential of 69 mV and a small Tafel slope of 77.58 mV dec −1 in 1 M KOH.
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CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Changqu Lin,Lulu Xu,Yue Zhuang,Peipei Ma,Hongli Wu,Haifeng Gan,Fei Cao,Ping Wei
The cleavage of C-C bonds to generate small molecules is a pivotal strategy for integrating shell bio-refinery products into the conventional chemical industry. Herein, we synthesized a novel bifunctional acetylacetone molybdenum-based catalyst with oxygen vacancies and acid sites (Ov-Mo-acac), which catalyze the retro -aldol reaction of N -acetylglucosamine (NAG), consequently the condensation with acetylacetone and dehydration to co-produce furan and pyrrole compounds. Reaction optimization resulted in a remarkable yield of 95 % for N-acetyl-3-acetyl-2-methyl pyrrole (AMAP) and 74 % for 5-(1,2-dihydroxyethyl)-2-methyl-3-acetylfuran (DMAF) from NAG at 90 ℃ for 3 h. XPS, EPR, and Raman confirmed the reduction of molybdenum from the Mo 6+ to Mo 5+ and Mo 4+ , and oxygen vacancies on the surface. Furthermore, the catalyst has Lewis and Brønsted acidic sites, as evidenced by py-FTIR and 1 H MAS NMR. The study offers a new approach to utilizing shellfishery waste and sheds the function of oxygen vacancies on Mo-based catalysts for the retro -aldol reaction of carbohydrates.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
·
IF 4.9
Qingtian Xu,Jierui Ye,Shuaibo Han,Yuebing Gao,Pan Chen,Siqun Wang,Qiang Wu,Qian Li
Renewable polymeric microcapsules hold promise for precisely controlled release of hydrophobic drugs (curcumin) in therapeutic treatment. However, there still remains challenges to stabilize the properties of microcapsules and to enhance encapsulation efficiencies of curcumin. By using an eco-friendly ternary deep eutectic solvent here, we successfully fabricated native cellulose nanofibrils, holocellulose nanofibrils, and lignocellulose nanofibrils containing both phytates and sulfate groups. In addition, a novel type of curcumin-loaded polymeric microcapsules with diameter of 10–20 μm were prepared by cellulose nanofibrils as stabilizing agents in Polylactide Pickering emulsion. The Pickering emulsions stabilized by P/N/S-containing cellulose nanofibrils, holocellulose nanofibrils, and lignocellulose nanofibrils are more stable than the unmodified cellulose nanofibrils-stabilized emulsion. The Pickering emulsion stabilized by 0.2 wt% P/N/S-containing lignocellulose nanofibrils exhibited the highest emulsion layer height and the zeta potential reached −39.74 ± 2.88 mV. Moreover, the highest encapsulation efficiency of curcumin can be up to 94.80%. Antimicrobial test revealed that curcumin in the polymeric microcapsules exhibited an excellent inhibitory effect on S. aureus and the antibacterial efficiency reached 98.66%. These results provided important information on the comparison of different cellulose nanofibrils-stabilized Pickering emulsions and the application of controlled release of curcumin incorporated polymeric microcapsules in drug delivery system.
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高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2018
·Vol. 28
·期 10
·1705876
·
IF 13.325
Fengyun Li,Chunyan Wang,Weiwei Guo
The development of highly efficient, recyclable, and multifunctional biocatalysts is of great importance for various applications, especially in biosensing. In this study, highly catalytic and recyclable DNAzyme functionalized poly- N -isopropylacrylamide (pNIPAM) microgels are prepared via one-step precipitation polymerization. The pNIPAM/DNAzyme microgels exhibit highly catalytic activities in aqueous solution at room temperature, and become hydrophobic and separable from the reaction mixture at temperature higher than the lower critical solution temperature of pNIPAM, which facilitate the recyclable utilization of these catalysts. Different kinds of DNAzyme functionalized catalytic microgels can be facilely prepared via the one-step synthesis procedure. Two typical catalytic DNA structures, the Mg 2+ -dependent DNAzyme and the hemin-G-quadruplex horseradish peroxidase (HRP)-mimicking DNAzyme, are chosen as model systems to validate the feasibility. These pNIPAM/DNAzyme microgel catalysts maintain 80% to 91% initial catalytic activity after eight times of catalysis recycling. Furthermore, the pNIPAM microgels by themselves provide additional interfaces to capturing an enzyme, glucose oxidase, which can cascade with the linked HRP mimicking DNAzymes, to form recyclable bi-enzyme cascading system for the sensing of glucose.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2017
·
IF 2.323
Ying Zhang,Yutian Chen,Yu Zheng,Xinxin He,Maogang He
The speed of sound in n-octane and isooctane (2,2,4-trimethylpentane) was measured by the Brillouin light scattering (BLS) method. The examined regions for n-octane are T = (297–580) K along five isobaric lines at p = 0.1, 4.0, 7.0, 10.0, and 12.0 MPa for liquid and T = (573–673) K along ten isobaric lines with p = (3.0–10.0) MPa for supercritical fluid. The examined regions for isooctane are T = (294–525) K along five isobaric lines at p = 0.1, 3.0, 6.0, 10.0, and 12.0 MPa for liquid and T = (543–630) K along six isobaric lines with p = (3.0–10.0) MPa for supercritical fluid. The relative expanded uncertainty of the speed of sound is estimated less than 1.3%. Polynomial representations for the speed of sound in liquid n-octane and isooctane were fitted to the experimental results, respectively. The AADs are 0.27% for n-octane and 0.19% for isooctane. The influence of temperature and pressure on the speed of sound was also analyzed. Moreover, the data were also used to assess the predicted ability of three equations of state for n-octane.
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CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Hanqin Liang,Kaihui Zuo,Yongfeng Xia,Dongxu Yao,Jinwei Yin,Yuping Zeng
Lu-Al-Si-O-N tapes with different thickness were used to join gas pressure sintered Si 3 N 4 ceramics. The microstructure of the joints and the influences of the joint thickness and joining temperature on the bonding strength of the as-joined Si 3 N 4 ceramics have been investigated. The highest bonding strength about ~ 300 MPa of the joined specimens was achieved by using 450 µm interlayer at 1450 °C. The existence of Si 3 N 4 nanowires was beneficial for the improvement of the bonding strength by interweaving the oxynitride glass matrix in the joint region.
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高影响因子
International Journal of Greenhouse Gas Control
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2017
·
IF 3.741
Yan Zhou,Yiheng Rao,Tielin Wang,Klaus-J. Jens
Piperazine (PZ) based amine blends are promising solvents for post-combustion CO 2 capture, but PZ can form potential carcinogenic nitrosamines from nitrite. In this work, the kinetics of the reaction between nitrite and PZ to form N-nitrosopiperazine (MNPZ) was determined in 0.1–0.5 mol L −1 PZ in the presence of 17–170 mmol L −1 formaldehyde at 60–135 °C. The nitrosation of PZ can be catalyzed by formaldehyde, a primary degradation product of PZ. And the reaction involving nitrite and PZ is first order in nitrite, formaldehyde, and hydronium ion. A kinetic model was established, and the activation energy is 33.6 ± 1.8 kJ mol −1 with a rate constant of 2.3 × 10 3 ± 0.4 × 10 3 L 2 mol −2 s −1 at 100 °C. The kinetics will be helpful to develop strategies to reduce nitrosamine formation and accumulation in PZ based CO 2 capture systems.
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APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Suyun Zhang,Xinxin Xiao,Taotao Lv,Xiaomeng Lv,Botao Liu,Wei Wei,Jun Liu
Exploring efficient and economical Pt-free electrocatalysts is of great significance for the electrocatalytic hydrogen evolution reaction (HER). However, the rational design on an industrial scale is a formidable challenge. Herein, we reported a facile calcination at controlled temperatures to fabricate rationally assembled cobalt nanoparticles embedded in defect-rich N-doped carbon nanotubes (Co-NCNTs), which was derived from low-cost dicyanadiamide thermally polymerized with cobalt precursor forming metal-organic frameworks, then further calculation leading to final products. The as-obtained samples were endowed with high content of N as electrocatalytic active site, defect-rich structure and excellent synergistic effect between cobalt nanoparticles and carbon nanotubes toward electrocatalytic HER . As expected, Co-NCNTs were highly active and long-term stable with onset potentials of c.a. 15 mV in acidic electrolytes (0.5 M H 2 SO 4 ), 70 mV in alkaline (1 M KOH) and 300 mV in neutral media (pH 7). Specially, to achieve the current density of 10 mA cm −2 , the overpotential of 103 mV in acid, 204 mV in alkaline and 337 mV in neutral media was obtained. The enhanced HER performance was discussed in detail by adjusting the molar ratio of precursor and metal species. Moreover, the present synthetic route is easy to scale up and expand to other non-noble metal and alloy.
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ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Rui Jiang,Jinhang Fan,Liangyou Hu,Yanpeng Dou,Xuhui Mao,Dihua Wang
An efficient catalyst for hydrogen evolution reaction (HER), nanostructured nitrogen-doped molybdenum carbide (β-Mo 2 C), is reported in this work. The catalyst is prepared via a novel one-step solid-state electrolytic reduction of a mixture of MoS 2 and polypyrrole nanofiber in molten CaCl 2 at 850 °C. As comparison, a series of Mo 2 C materials are prepared by the method using different carbon precursors. TEM tests show that the as-prepared N-doped Mo 2 C is composed of near-spherical nanoparticles with the particle sizes of about 40–60 nm. Nitrogen-doping of Mo 2 C is shown to facilitate the exposure of active centers on the surface of the sample, concurrently modify the electronic property of Mo 2 C to promote electron transfer for HER. As a result, the optimized N-doped Mo 2 C (Mo 2 C- PPyF -1/1) displays a low onset potential of 78.1 mV for HER and a Tafel slope of 59.6 mV dec −1 in 0.5 M H 2 SO 4 , meanwhile exhibits high activity and stability in a broad pH range (0–14). Furthermore, the synthesis method is extended to fabricate other N-doped transition metal carbides (NbC, TaC and TiC). All of the N-doped materials exhibit significantly enhanced activity compared to the undoped ones.
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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
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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.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Xu Liu,Yanping Liu,Minghao Jin,Chenxi Xu,Yushan Tian,Miao Zhou,Wei Wang,Gangyong Li,Zhaohui Hou,Liang Chen
Owing to high theoretical capacity, low cost and abundant availability, manganese oxides are widely viewed as promising anodes for lithium–ion batteries (LIBs). Nonetheless, their practical application is significantly hindered by poor electrical conductivity, sluggish reaction kinetics and substantial volume change. In this work, an ingenious polypyrrole encapsulation followed by pyrolysis strategy is proposed to produce N–doped carbon encapsulated Mn 2 O 3 /MnO heterojunction (Mn 2 O 3 /MnO@NC) by using mechanically ground Mn 3 O 4 /C 3 N 4 mixture as the precursor. The results show that the selection of precursor plays a pivotal role in the successful preparation of Mn 2 O 3 /MnO@NC hybrid. It is revealed that the uniform encapsulation by N–doped carbon significantly enhances the conductivity and structural stability of the final product. Concurrently, the Mn 2 O 3 /MnO heterojunction within the resultant hybrid exhibits a unique quantum–dot size, which effectively shortens ion transport pathways and exposes the active sites for lithium storage. Additionally, experimental observations and theoretical calculations demonstrate that the built–in electric fields generated at the interfaces of Mn 2 O 3 /MnO heterojunction accelerate the charge transfer and ion diffusion, thereby enhancing the electrochemical reaction kinetics. As a result, the Mn 2 O 3 /MnO@NC hybrid displays much enhanced lithium storage performance. Evidently, our work offers a good guidance for the design and synthesis of advanced transition metal oxide/carbon anodes for LIBs.
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