Advanced Materials Interfaces
·
2022
·Vol. 9
·期 14
·2200333
·
IF 6.389
Xiaoyan Yuan,Huanhuan Li,Aiming Sha,Shengyan Huang,Bo Li,Shouwu Guo
Materials with 1D structure exhibit a remarkable advantage for losing electromagnetic (EM) wave energy. Herein, flexible Mo 2 C-modified SiC/C nanofibers (Mo-SiC/C NFs) are synthesized for the first time by co-electrospinning and subsequent high-temperature pyrolysis, using polycarbosilane (PCS) and molybdenum acetyl acetone (MoO 2 (acac) 2 ) as precursors. It is found that the polymer derived temperature of PCS is significantly decreased by introducing MoO 2 (acac) 2 , as well as endowing the SiC/C NFs with good flexibility, high crystallinity, and remarkable microwave absorption performance. The as-prepared fibers dispersed in paraffin with a low filler loading (15 wt%) exhibit a minimum reflection loss (RL, dB) of -62.5 dB, and a wide effective absorption bandwidth (EAB, RL<-10 dB) of 6.8 GHz at 2.75 mm. Meanwhile, the EAB of the hybrid can cover the whole X-band and most of the C-band by modulating its thickness. These high-efficient performances mainly originate from the specific 1D microstructure, abundant interfaces and defects, and synergistic effect among SiC, Mo 2 C, and C matrix. Thus, this work offers a way to explore flexible SiC/C NFs as a promising candidate with lightweight and wide EAB for EM wave absorption.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2023
·Vol. 28
·期 6
·2508
·
IF 4.6
Hong Qiu,Xiaohui Ma,Hongxia Fan,Yueyan Fan,Yajie Li,Hualei Zhou,Wenjun Li
Molybdenum-based cocatalyst being used to construct heterojunctions for efficient photocatalytic H2production is a promising research hotspot. In this work, CdIn2S4was successfully closely supported on bulk Mo2C via the hydrothermal method. Based on their matching band structures, they formed a Type Ⅰ heterojunction after the combination of Mo2C (1.1 eV, −0.27 V, 0.83 V) and CdIn2S4(2.3 eV, −0.74 V, 1.56 V). A series of characterizations proved that the heterojunction composite had higher charge separation efficiency compared to a single compound. Meanwhile, Mo2C in heterojunction could act as an active site for hydrogen production. The photocatalytic H2production activity of the heterojunction composites was significantly improved, and the maximum activity was up to 1178.32 μmmol h−1g−1for 5Mo2C/CdIn2S4composites. 5Mo2C/CdIn2S4heterojunction composites possess excellent durability in three cycles (loss of 6%). Additionally, the mechanism of increased activity for composites was also investigated. This study provides a guide to designing noble-metal-free photocatalyst for highly efficient photocatalytic H2evolution.Keywords:noble-metal-free;Mo2C;CdIn2S4;heterojunction;carrier separation
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 16
·7819-7827
·
IF 11.301
Yuanyuan Zhu,Xu Ji,Lufeng Yang,Jin Jia,Shuang Cheng,Hailong Chen,Zhong-Shuai Wu,Donata Passarello,Meilin Liu
Mo2C is one of the few compounds that possess good electronic conductivity. Meanwhile, it possesses a natural 1D zigzag tunnel structure that is ideally suited for fast ion diffusion. Here, an effective approach is demonstrated for fabrication of structurally stable N-doped Mo2C/C nanobelts. They demonstrate high and fast energy storage ability with initial capacitances of 1139 C g−1 at 1 mV s−1, 151 C g−1 at an extremely high scan rate of 2000 mV s−1 and 208 C g−1 at a discharge current density of 200 A g−1. After electrochemical activation of cycling, the capacity is continuously enhanced and much higher capacitances of 2523 C g−1 at 1 mV s−1 and 1403 C g−1 at 50 A g−1 are achieved after 15 000 cycles at 50 mV s−1. Using the power law, it is evaluated that a surface-controlled capacitive process makes the main contribution to the capacity, which is over 90% when the scan rates are higher than 10 mV s−1 and still high as 73% at 1 mV s−1. From in situ synchrotron XRD, it is found that there is a negligible change in the crystal structure and volume during charging/discharging, reflecting an insertion-type charge storage mechanism.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2023
·
IF 3.6
Xiao-Chun Deng,Xin Lan,Ya-Long Wang,Guo-Hua Zhang
Mo 2 C doped WC-10Co alloys were prepared via an in - situ synthesis method composed of steps of spray drying, roasting, carbothermal pre-reduction and carbonization-vacuum sintering. The effects of Mo 2 C content on the microstructure and mechanical properties of cemented carbides were studied in detail. The results showed that WC and Mo 2 C formed a complete solid solution by the current method. With the increase of Mo 2 C content from 0 wt% to 0.5 wt%, the effects of solution strengthening and fine grain strengthening were obvious, and the grain size was decreased from 0.72 ± 0.32 μm to 0.62 ± 0.27 μm, while the hardness was improved from 1316 ± 20 HV 30 to 1549 ± 14 HV 30 . However, the (W, Mo)C solid solution would deteriorate the fracture toughness of the alloys. With the further increase of Mo 2 C content to 9 wt%, the lattice distortion in the solid solution became more serious. Meanwhile, the dissolution of more Mo 2 C in the liquid Co further weakened the dissolution-precipitation process of the solid solution, thus inhibiting the growth of grains and increasing the hardness of the alloys. In addition, with the increase of Mo 2 C content, the dominant fracture mode of the alloy changed from transgranular fracture to intergranular fracture .
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2020
·
IF 8.247
Chang Wu,Yuyang Hou,Jicheng Jiang,Haipeng Guo,Hua-Kun Liu,Jun Chen,Jiazhao Wang
Li–O 2 batteries has been widely investigated for its ultra-high capacity as next generation batteries. Nevertheless, some problems like sluggish kinetic reaction and instability hugely impede the practical use of Li–O 2 batteries. In this work, Mo 2 C/MoO 2 @RGO heterostructures was fabricated by in-situ growth of Mo 2 C between MoO 2 and RGO during calcination and being employed as cathode to explore the synergistic effect in Li–O 2 batteries. As a result, Mo 2 C/MoO 2 @RGO exhibits good specific capacity with 2365 mAh g −1 , high round-trip efficiency (89% at first cycle) and improved cycling performance. Density functional theory calculations indicated that the Mo 2 C/MoO 2 @RGO heterostructures have better capability of oxygen adsorption than sole constituent (Mo 2 C@RGO or MoO 2 @RGO), which triggers the formation of film-like amorphous discharge products, leading to lower overpotential and stable performance. Our study reveals the important role of heterostructures in Li–O 2 batteries system and demonstrates a promising design strategy for heterostructured catalyst.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2023
·Vol. 34
·期 7
·1-13
·
IF 2.8
Guo Yitong,Du Jingyang,Hu Meihua,Wei Bin,Su Taichao,Zhou Aiguo
In this paper, the thermoelectric (TE) performance of Bi 2 Te 3 was improved by the incorporation of Mo 2 C MXene, which is a novel two-dimensional material with moderate TE performance. The TE properties of Mo 2 C MXene were characterized from bulk samples bonded with 5 wt% Al sintered by spark plasma sintering (SPS) at 623 K for 6 min. Due to the very weak TE performance of Al, the performance of Mo 2 C MXene/Al composite reflects that of Mo 2 C MXene. It is an N-type conductor with the Seebeck coefficient of − 9.25 µV/K at 600 K. This is the first report to characterize the TE performance of Mo 2 C MXene bulk samples. Thereafter, Bi 2 Te 3 /Mo 2 C MXene composite powders were prepared from Mo 2 C MXene powers and precursors of Bi 2 Te 3 by hydrothermal method at 453 K for 24 h. The bulk samples of Bi 2 Te 3 incorporated with Mo 2 C MXene was obtained by SPS at 523 K for 7 min. The composites are N-type conductors. The electrical conductivity was remarkably increased with the content of Mo 2 C MXene, while the thermal conductivity slightly decreased. The sample with 5 vol% Mo 2 C MXene showed the optimal thermoelectric properties, and its ZT value was 0.26 at 473 K. At 450 K, the ZT value (~ 0.25) of that sample was 78.6% higher than that of Bi 2 Te 3 (~ 0.14). This is the first report on regulating TE performance by the incorporation of Mo 2 C MXene, a 2D material with intrinsic TE performance.
研究领域:
材料科学
·
热电材料
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Weiwen Wang,Lu Zhang,Chen Gao,Huang Zhu,Xing Yang,Chong Cheng,Xikui Liu,Shuang Li
Mo-based materials have been explored as promising non-precious metal catalysts for hydrogen evolution reactions (HER); however, their long-term stability under strong acidic and alkaline electrolytes to meet industrial requirements is still a remaining challenge. Herein, we described a methodology for fabricating a stable Mo-based HER chainmail catalyst, which is derived from pyrolysis of Mo, Ni adsorbed two-dimensional covalent orgainnic framework (COF). The derived chainmail catalyst shows an in-situ formed Mo 2 C-MoNi 4 structure embedded in nitrogen-doped carbon (Mo 2 C-MoNi 4 @NC), which shows excellent activities for HER with a small overpotential of 104 mV to deliver 10 mA cm −2 . Most importantly, with the protective effect of the nitrogen-doped graphene shell layer, the Mo 2 C-MoNi 4 @NC chainmail catalyst maintained remarkable stability after chronopotentiometry testing even for 140, 000 s both in acidic and alkaline media, proving its excellent durability. This work sheds new light on designing stable non-noble-metal-based catalysts for wide applications in energy conversion.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS & DESIGN
·
2020
·
IF 6.289
Hu Sun,Guanghui Li,Jun Luo,Mingjun Rao,Zhiwei Peng,Tao Jiang
Existing nano-Mo 2 C preparation methods suffer from expensive raw materials, subtle operation demands and complex synthesis steps. Herein, both theoretical and experimental studies were performed to develop a more efficient and economical method for nano-Mo 2 C preparation. Reaction thermodynamics of gas-vapor system of CH 4 -MoO 3 -N 2 indicates that high-proportion inert gas significantly increases the required carbonization potential (CO/CO 2 ) for Mo 2 C formation, but surplus carbon produced from methane decomposition can trigger water gas producing reaction and Boudouard reaction to help meet the requirement. Nano-Mo 2 C was then synthesized by mixing N 2 -carried MoO 3 vapor with CH 4 under varying conditions including temperature, gas flowrate and vapor concentration. It is found that MoO 3 vapor experienced conversions to monoclinic MoO 2 to cubic Mo to hexagonal Mo 2 C, and all these stages could be finished in as short as about 6 s at 1100 °C with initial molar ratio of CH 4 to MoO 3 over 3.5. The final products were present as porous plate-like single crystals or chain-like polycrystals, which are determined by initial vapor concentration and gas flowrate. Furtherly, electrocatalytic properties of Mo 2 C nanocrystals for hydrogen evolution reaction were measured, and the sample with the largest specific surface area and cleaner surface showed competitive performance over reported nano-Mo 2 C.
研究领域:
材料科学
·
化学工程
·
能源科学
✓ 已验证
DOI
高影响因子
NANO
·
2021
·
IF 1.556
T. Jiang,X. Meng
Surface and interface engineering have shown broad application prospect in energy conversion. Mo 2 C-C/Sb 2 S 3 composites have been synthesized by coupling Mo 2 C-C composites and Sb 2 S 3 nanowires with coupling agent. The performance of the devices has been investigated. Under irradiation by light source, the device showed better electrical contact, fast response speed (rise time 0.135 s, decay time 0.132 s) and larger on/off ratio ( 1 . 5 × 1 0 2 ) than the device which assembled by mechanical mixing ( 1 × 1 0 2 ) and pure Sb 2 S 3 nanowires (47), respectively. The performance has been enhanced by modifying the surface and interface of materials. This approach provides a new idea to enhance the high-performance photodetectors and other inventive optoelectronic devices.
研究领域:
材料科学
·
光电子学
✓ 已验证
DOI
高影响因子
ACS Catalysis
·
2024
·
IF 11.3
Haoquan Guo,Jiwu Zhao,Yu Chen,Xinyu Lu,Yue Yang,Chenrong Ding,Lizhi Wu,Li Tan,Jinlin Long,Guohui Yang,Yu Tang,Noritatsu Tsubaki,Xiaoli Gu
Lignin derivatives are one class of attractive alternative feedstocks for the production of renewable biofuels. Herein, hydrodeoxygenation (HDO) of lignin derivatives was carried out using a single-atom catalyst (SAC) comprised of Ni1 SAC on β-Mo2C. A number of lignin-derived compounds have been investigated, and nearly 100% yield of biofuel molecules was converted from various lignin derivatives through the HDO reaction, demonstrating that Ni1/β-Mo2C has remarkable potential for the production biofuels through catalytic hydrodeoxygenation of lignin derivatives. The reaction mechanism of DHE over single-atom catalyst Ni1/β-Mo2C was confirmed based on comprehensive characterizations of catalysts and DFT calculations. Interestingly, the Ni single-atom active sites alter the reaction pathway by shifting the geometry of the adsorbed intermediate from a vertical to horizontal conformation, which lowered the reaction energy barrier and improved the selectivity to biofuel molecules, resulting in extraordinary catalytic activity. This study suggests an avenue for single-atom catalysis in chemical transformations of lignin derivatives into biofuels.
研究领域:
化学工程
·
催化科学
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2023
·
IF 5.9
Sen Jin,Huijuan Jing,Libo Wang,Qianku Hu,Aiguo Zhou
Mo2C MXene is a two-dimensional material, which can be applied as a co-catalyst to significantly enhance the photocatalytic performance of CdS for H2 production. To understand the effect of the synthesis process of Mo2C MXene nanosheets on the catalytic performance, in this paper, Mo2C MXene was made from Mo2Ga2C by hydrothermal etching in different etchants. Diverse cations (Li+, Na+, K+, or NH4+) in etchants resided on the surface of Mo2C MXene nanosheets. Then, the samples were used to construct CdS/Mo2C-MXene composites for photocatalytic H2 evolution. Among them, Mo2C MXene with Li+ shows the best photocatalytic H2 production rate of 22,048 μmol g–1 h–1 under visible light. The remarkable performance arises from the modification at the nanoscale of Mo2C MXene with Li+, thereby resulting in better photoabsorption behavior, high separation efficiency of photogenerated carriers, and fast charge transfer at the heterointerface. Moreover, the energy band structures explain that the changes of band gap and the position of the conductive band in the photocatalyst tuned by cations are also key to affect photocatalytic activities.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
MICROCHIMICA ACTA
·
2021
·Vol. 188
·期 5
·1-7
·
IF 5.833
Lin Zhenfeng,Liu Xin,Li Yangzi,Li Changxiang,Yang Liu,Ma Keke,Zhang Zhenwei,Huang Huayu
Two-dimensional Mo 2 C/Mo 2 N composites were synthesized by high temperature ball milling and used as support materials for fabricating a chlorpyrifos (CPF) aptasensor. Gold nanoparticles (Au NPs) were electrodeposited on the surface of a Mo 2 C/Mo 2 N-modified electrode to connect with the ferrocene (Fc) probe via Au–S bonds. The Fc probe can hybridize with the aptamer probe to form a double-stranded structure. The addition of CPF made the double strands melt and the Fc probe approached the surface of the electrode, thereby resulting in amplification of the electrochemical response. The current response of the aptasensor for detecting CPF in solutions linearly varied from 0 to 400 ng mL −1 (with a maximum at 0.98 V vs. Ag/AgCl). The Au NPs/Mo 2 C/Mo 2 N composites exhibited satisfactory electrochemical behavior due to their excellent electrical conductivity and large surface area. This ultrasensitive aptasensor showed a low limit of detection of 0.036 ng mL −1 . It was applied to determine CPF in real samples with acceptable recoveries from 94.7 to 116.7%, and the relative standard deviation was from 2.57 to 7.08%. Graphical abstract
Schematic diagram of the manufacturing process of the aptasensor. Electrochemical aptasensor based on Mo 2 C/Mo 2 N/Au NP composites show excellent performance in detecting CPF.
研究领域:
分析化学
·
环境科学
·
农业科学
✓ 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）