JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2020
·Vol. 95
·期 6
·1748-1755
·
IF 2.75
Ting Wang,Junnan Wei,Yunchao Feng,Huai Liu,Xing Tang,Xianhai Zeng,Yong Sun,Tingzhou Lei,Lu Lin
BACKGROUND Biomass holds the promise to provide a sustainable future for the chemical industry. 2, 5-Bishydroxymethylfuran (BHMF) is a versatile bio-based diol with a broad range of potential applications in many polymeric materials, artificial fibers and drugs. However, the controlling of the BHMF selectivity in hydrogenation of biomass-derived 5-hydroxymethylfurfural (HMF) with complex transformation pathways is always a great challenge especially under solvent-free conditions in which many side reactions may occur due to its rich reducible groups. RESULTS A facile and effective approach was developed for the selective synthesis of BHMF by solvent-free hydrogenation of a deep eutectic mixture consisting of HMF (75 wt%) and choline chloride (ChCl), by which a BHMF selectivity up to 94.6% was gained at full HMF conversion over Raney Co at 100 °C in 4 h. In addition, the HMF conversion and selectivity toward BHMF can be regulated and controlled through altering the strength of hydrogen-bonding interactions of HMF-based deep eutectic mixtures (ChCl–HMF mixtures). CONCLUSION We developed an effective approach that allows the solvent-free synthesis of BHMF via hydrogenation of HMF-based deep eutectic mixtures. The extraordinary BHMF selectivity in the solvent-free hydrogenation of HMF is reasonably attributed to the hydrogen-bonding interactions formed between ChCl and HMF/BHMF which greatly suppresses the side reactions of HMF and the over-reduction of BHMF. © 2020 Society of Chemical Industry
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Reaction Kinetics Mechanisms and Catalysis
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2020
·Vol. 129
·期 2
·865-881
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IF 1.52
Liu Minjie,Zhang Hao,Wang Junyan,Zhao Guoming,Liu Di
A Co–N–C catalyst was fabricated via pyrolysis–reduction process. Dehydrogenation/hydrogenation and base catalysis performances of the Co–N–C catalyst were investigated by using the reductive coupling of nitroarenes with alcohols and aldol condensation as probe reactions. Various characterizations were performed to explore effects of reduction and pyrolysis temperature on the structure/composition and basicity of the Co–N–C catalyst, and the relationship between structure-dehydrogenation/hydrogenation and base catalysis performance was discussed accordingly. Two different structures of Co–N–C catalyst (Co–N–C/C 3 N 4 and Co–N–C/CNT) were obtained in different pyrolysis temperature. Co–N–C-600 with C 3 N 4 exhibits very weak catalytic performance owe to its poor pore system and active phase. Dehydrogenation/hydrogenation behaviors of Co–N–C/CNT depend on the amount of Co–N, graphitic N in Co–N–C, while the basicity of Co–N–C is closely related to the content of N species, particularly pyrrolic N and pyridinic N. The appropriate pyrolysis temperature benefits the formation of active species, developed pore organization and strong basicity. And, the H 2 reduction improve dehydrogenation/hydrogenation activity of Co–N–C/CNT because reduction can destroy carbon coating layers to expose more Co–N species and promote the transformation of N species to graphitic N. Meanwhile, H 2 reduction increases the contents of graphitic N and reduces the content of pyrrolic N and pyridinic N, thus weakening catalyst basicity and consequently reducing base catalytic activity of Co–N–C/CNT.
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INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
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2020
·
IF 3.407
Zhaoran Chen,Dejiang Ma,Shanmin Wang,Wenhao Dai,Pinwen Zhu,Yiqing Zhu,Baochang Liu
Ti-coated diamond with different particle sizes and proper amounts of cubic boron nitride (cBN) was used to fabricate polycrystalline diamond composite (PDC) with improved wear resistance and thermal stability under high temperature and high pressure (5.5–6.5GPa, 1500–1650 °C). The ratio of Ti-coated diamond powder, cBN powder and normal diamond powder was W 30 – 50 : W 4 – 8 : W 0 – 1 = 70: 15: 15. Cobalt (Co) was used as a binder, and cemented tungsten carbide was used as a substrate to sinter a new high-performance PDC. Ti and TiC on the surface of Ti-coated diamond reacted with cBN under high temperature and high pressure to generate new ceramic phases such as TiB 2 , TiN and TiN 0.3 , which have high hardness and good wear resistance. Compared with the conventional PDC, the impact toughness and wear resistance of PDC with Ti-coated diamond and cBN addition were enhanced by 19% and 28%, respectively. The ceramic phase acts as a protective barrier, which enhances the initial graphitization and oxidizing temperature to 942–950 °C, which were 162–170 °C higher than the conventional PDC. The new ceramic barrier wrapped around the surface of the diamond and Co after the formation of the D-D (diamond-diamond) bonding will give priority to the oxidation reaction of Co and diamond with oxygen, which prohibits cobalt-catalytic graphitization of diamond, meeting the needs of PDC thermal stability and wear resistance in the field of drilling.
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ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Wei Li,Yanli Niu,Xiuju Wu,Fawang Wu,Tianhao Li,Weihua Hu
Metal selenides attract great research interest as oxygen evolution reaction (OER) electrocatalysts. Herein, we report heterostructured bimetallic cobalt–iron diselenide nanoparticles with abundant vacancies and strong electronic coupling supported on carbon nanorod (CoSe2/FeSe2@C) as a highly efficient OER electrocatalyst. It is synthesized with a facile templating-engaged synthetic strategy and exhibits outstanding OER catalytic performance including high activity and good durability in alkaline medium. It affords a current density of 10 mA cm–2 at a low overpotential of 291 mV with small Tafel slope of 62 mV dec–1, which significantly outperforms the benchmarking RuO2 catalyst. The outstanding OER performance is found to be arising from its integrated advantages of the modulated electronic structure, abundant active sites, high electric conductivity, and large surface area endowed by its unique heterostructure and composition. This work exemplifies a feasible route to designing heterogeneous nanomaterials and enriches the OER electrocatalytic application of transition metal selenide-based hybrid materials.
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Journal of Energy Chemistry
·
2020
·
IF 7.216
Jia Sun,Lei Du,Baoyu Sun,Guokang Han,Yulin Ma,Jiajun Wang,Hua Huo,Pengjian Zuo,Chunyu Du,Geping Yin
ABO 3 -type perovskite oxides (e.g., LaCoO 3 ) with flexible and adjustable A- and B-sites are ideal model catalysts to unravel the relationship between the electronic structure and electrocatalytic activity (e.g., oxygen reduction/evolution reactions, ORR/OER). It has been well understood in our recent work that the secondary metal dopant at B-site (e.g., Mn in LaMn x Co 1 −x O 3 ) can regulate the electronic structure and improve the ORR/OER activity. In this work, the Mn-Ni pairs are employed as the dual dopant in LaMn x Ni y Co z O 3 ( x + y + z = 1) catalysts toward bifunctional ORR and OER. The structure–property relationships between the triple metal B-site (Mn, Ni and Co) and the electrochemical performance are particularly investigated. Compared to the individual Mn doping (e.g., LaMnCoO 3 (Mn:Co = 1:3) catalyst), the dual Mn-Ni doping significantly improves the ORR mass activity@0.8 V by 1.54 times; meanwhile, the OER overpotential@10 mA cm −2 is reduced from 420 to 370 mV, and the OER current density at 1.55 V is increased by 2.43 times. Reasonably, the potential gap between E ORR @-1 mA cm −2 and E OER @10 mA cm −2 is achieved as only 0.76 V by using the optimal LaMn x Ni y Co z O 3 ( x : y : z = 1:2:3) catalyst. It is revealed that the dual Mn-Ni dopant efficiently optimizes electron structures of the LaMnNiCoO 3 (1:2:3) catalyst, which not only decreases the e g orbital electron number, but also modulates the O 2p-band closer to the Femi level, accounting for the enhanced bifunctional activity.
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JOM
·
2020
·Vol. 72
·期 3
·1279-1285
·
IF 2.054
Xia Yang,Zhao Jinlong,Dong Zhaowang,Guo Xueyi,Tian Qinghua,Liu Yong
Cobalt-chrome-molybdenum (Co-Cr-Mo) alloy possesses outstanding strength, wear, and corrosion resistance and is a good material candidate for making dental and orthopedic implants. Spherical Co-Cr-Mo powder for additive manufacturing is usually costly due to the high-temperature melting processes and low yield of the powder with desirable particle size in the conventional melt-atomization process. A novel process for making spherical Co-Cr-Mo alloy powder through a simple meltless granulation and sintering process is described herein. The results indicate that the compositional segregation problem can be overcome and high-temperature operation avoided. Segregation-free powder was obtained after sintering above 1200°C. The powder was purified during sintering in a hydrogen atmosphere. The hydrogen purification mechanism is discussed with the aid of thermodynamic modeling using HSC Chemistry software. The oxygen content in the final powder can be controlled to < 0.2 wt.% for powder with particle size < 107 µ m. The final powder retained good spherical morphology.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2021
·
IF 8.128
Xiaoming Wang,Qianqian Peng,Xilin Zhang,Xucheng Lv,Xin Wang,Yongzhu Fu
Refractory high-entropy alloy nanocomposites (HEA-NPs) are important class of materials with unique structure and potential applications. Although several synthetic methods have been reported, developing novel routes to prepare nanoscale HEA-based catalysts facilely is still urgently desired. This work takes advantage of confinement assisted arc and plasma shock (APS) to prepare a series of HEA-NPs by regulating the type and proportion of metal precursors. The phase constitutes and morphology of the HEA-NPs are fully characterized. The prepared refractory HEA-NPs possesses five highly dispersed metal components, including titanium (Ti), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo) and simultaneously exhibits an uniform hexagonal morphology of nanocrystals . By taking advantage of its unique corrosion resistance , TiNbTaCrMo HEA-NPs can function as a promising candidate for electrocatalytic hydrogen evolution reaction (HER) in natural seawater . And its catalytic performance after alloying is significantly enhanced compared with the elemental metal. Theoretically, the promoted HER activity can be attributed to the strong adsorption for the various metal components in HEA-NPs caused by the upshifting d -band center close to the Fermi level . Furthermore, this confinement strategy can be further extended to synthesize other HEA-NPs. Our strategy provides a novel method to synthesize various HEA-NPs for further catalytic application.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2021
·
IF 5.816
Jianxun Zhao,Jian Lv,Dayong Liu,Wanqiang Liu,Heng Liu,Peng Chen,Xinwei Wang,Yong Cheng,Xin Guo
Co 2 B alloy was synthesized via the method of high temperature solid phase. Carbon fiber (CF) was prepared from cotton by calcination process. The addition of carbon fiber and Co 3 O 4 improves corrosion resistance and charge transfer speed of the composite material electrode . The R ct value of Co 2 B + 1 wt.% CF was 360 mΩ, lower than the other composite electrode could reduce charge transfer resistance . The overall electrochemical performance of Co 2 B + 2 wt.% Co 3 O 4 + 1 wt.% CF was best among all the electrodes, and its C max could reach 715.3 mAh/g. The high conductivity and multiple reaction sites provided by carbon fiber and the catalytic effect of Co 3 O 4 may be the main reasons for the improvement of electrochemical performance, which enhance the kinetic performance of electrochemical reactions . The synergistic effect of carbon fiber and Co 3 O 4 improves the electrochemical hydrogen storage properties of Co 2 B alloy. This work presents a simple and effective method to improve the electrochemical hydrogen storage performance of cobalt-boron alloys by adding transition metal oxides and carbon materials derived from biomass.
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MICROCHIMICA ACTA
·
2021
·Vol. 188
·期 11
·1-9
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IF 5.833
Xia Yixuan,Ma Yuzhi,Wu Yuntao,Yi Yinhui,Lin Huiyu,Zhu Gangbing
A proof-of-principle concept for free-electrodeposited anodic stripping voltammetry (ASV) sensing of Cu 2+ is proposed by using Ti 3 C 2 T x MXene/carbon black (Ti 3 C 2 T x @CB) nanohybrids as electrode materials. Owing to the high adsorption and reduction capability of Ti 3 C 2 T x towards Cu 2+ , Ti 3 C 2 T x MXene enables Cu 2+ to be immobilized and self-reduced directly to form Cu 0 on the Ti 3 C 2 T x @CB electrode surface. As a result an oxidation peak current appears from the re-oxidation of Cu 0 via differential pulse voltammetry. Carbon black (CB) was introduced to prevent Ti 3 C 2 T x Mxene aggregation and improve the related electron transfer as well as enhance their surface area. After optimizing various conditions, a considerable low limit of detection (4.6 nM) and a wide linear range (0.01–15.0 μM) for Cu 2+ were achieved at the working potential from − 0.3 V to 0.0 V (vs SCE). Relative standard deviation (RSD) of eight individual Ti 3 C 2 T x @CB electrodes is 3.72%, and the recoveries from tap water sample and lake water sample were in the ranges of 97.0–108% and 104–107%, respectively. Graphical abstract
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APPLIED SURFACE SCIENCE
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2021
·
IF 6.707
Miao Fu,Zhiying Feng,Jing Wang,Ying Zhu,Lanlan Gan,Xiaoming Yang
Room-temperature phosphorescence (RTP) materials have harvested enormous attention owing to their advanced optical properties, providing their possibility of the wider applications. Here, we designed a facile strategy to synthesize phosphorus and nitrogen co-doped carbon dots, while creatine provided the carbon and nitrogen source (CDs@creatine). Meanwhile, the as-prepared CDs@creatine exhibited the bright blue fluorescence in aqueous suspension, and showed the green RTP while being fixed on the filter paper. Significantly, the fluorescence of CDs@creatine was quenched by the introduction of warfarin, whereas their RTP was simultaneously enhanced. Specifically, their fluorescence reduction was mainly ascribed to static quenching effect (SQE) and inner filter effect (IFE). In addition, the abundant hydroxyl groups on the surface of CDs@creatine interacted with the carbonyl groups of warfarin to form hydrogen bonds which rigidified the excited triplet against the non-radiative transition, and thus leading to their enhanced phosphorescence. Therefore, a dual-channel detecting strategy of warfarin has been successfully proposed with the fluorescent linear range from 8 × 10 −3 to 8 × 10 −7 M and phosphorescent linear range of 2 × 10 −5 to 1 × 10 −8 M, which established a new way of assaying warfarin. Besides, CDs@creatine served as both fluorescent and phosphorescent ink, and were applied for painting and information encryption.
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SENSORS AND ACTUATORS B-CHEMICAL
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2019
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IF 6.393
Chunsong Lu,Jie Liu,Lanlan Gan,Xiaoming Yang
Distinguishing the isomers is considered to be challenging, and shows the great importance in the biochemical and pharmaceutical fields. Herein, the blue carbon dots (CDs) were successfully raised on the basis of a facile hydrothermal way, since Cryptococcus served as the carbon source. Importantly, the as-prepared CDs were employed to achieve the differentiation and detection of two benzenediols. To be specific, the fluorescence of CDs was enhanced once m -benzenediol (resorcinol) was added, while introducing p -benzenediol (hydroquinone) lead to their fluorescence quenching. Towards the mechanism, the addition of m -benzenediol promoted the formation of hydrogen bonds between m -benzenediol and CDs, and thus resulting in their enhanced fluorescence. In contrast, the fluorescence quenching occurred due to the electron transferring from the rich-electrons of CDs to p -benzoquinone, when p -benzenediol was oxidized to be p -benzoquinone. Therefore, a differentiating strategy of two isomers has been proposed, and also contributed to detecting m -benzenediol and p -benzenediol concentrations in the ranges of 2 × 10 −3 to 1 × 10 −7 M and 2 × 10 -5 to 2 × 10 -9 M, respectively. Although there already existed the high performance liquid chromatography and other chemical methods for determining benzenediols, the current strategy provided a new way of distinguishing and assaying the isomers of benzenediols.
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CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Yuhao Cai,Bing Tang,Liying Bin,Shaosong Huang,Ping Li,Fenglian Fu
This work prepared a novel adsorbent with multi-layer structure and verified its adsorption mechanism for various ionic dyes. By the methods of cross-linking and surface modification, a multi-layer composite (CTAB-Chitosan@Al 2 O 3 ) was successfully synthesized, which showed an excellent adsorptive performance for various anionic dyes. The results indicated that the outer layer and the core adsorbed Congo Red (CO) and Reactive Blue (RB) well, and the middle layer played a leading role on adsorbing Methyl Orange (MO). The maximum adsorption capacity of CTAB-Chitosan@Al 2 O 3 for MO, CO and RB was 327.87, 1250.00 and 1017.90 mg/g, respectively. The characteristics of the as-synthesized adsorbent were revealed by multi-method, including Fourier Transform Infra-Red spectra, X-ray powder diffraction, X-ray photoelectron spectra, Scanning Electron Microscope, Brunauer-Emmet-Teller surface area and Thermogravimetric analyzer, which verified that the comprehensive effects of electrostatic interaction and hydrogen bond was the main mechanism for CTAB-Chitosan@Al 2 O 3 to adsorb ionic dyes. The pH value obviously influenced the surface charge of CTAB-Chitosan@Al 2 O 3 , and it was a convenient approach to regulate and control the adsorption process by only adjusting the pH value.
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