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
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环境科学
·
农业科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CATALYSIS LETTERS
·
2024
·
IF 2.3
Chen Yonghui,Zhao Jiafu,Song Mingzhu,Luo Shaojuan,Xie Shaoqu,Yan Kai
The development of safe, low-cost and highly active non-precious metal electrocatalysts plays a vital role in efficient hydrogen production. Herein, Mo 2 C/Mo 2 N heterostructure was in-situ synthesized by a two-step method for excellent hydrogen evolution performance at a universal pH range. The results show that the optimized MoCN-750-2h only needs 86.5, 102.5 and 120.5 mV overpotentials to reach 10 mA·cm −2 in alkaline, acidic and neutral media, respectively. Not only that, MoCN-750-2h had a low Tafel slope (37.2 and 88.5 mV·dec −1 ) in alkaline and neutral media, implying that catalytic kinetic is close to the level of Pt/C. These results can be attributed to reasonable C and N content in MoCN-750-2 h, optimizing the electron cloud distribution of Mo 2 C/Mo 2 N heterostructure to boost hydrogen production. Graphical Abstract MoCN heterostructure was in-situ synthesized by a two-step method for excellent hydrogen evolution performance at a universal pH range. The optimized electron cloud distribution of Mo 2 C/Mo 2 N would promote the formation of electron transfer channels, boosting the hydrogen evolution catalytic activity of the heterostructure. The MoCN heterostructure only needs 86.5,102.5 and 120.5 mV overpotentials to reach 10 mA·cm −2 in alkaline, acidic and neutral media, respectively. Not only that, MoCN-750-2 h had a low Tafel slope (37.2 and 88.5 mV·dec −1 ) in alkaline and neutral media, implying that catalytic kinetic is close to the level of Pt/C.
研究领域:
材料科学
·
电化学
·
催化
✓ 已验证
产品关联
DOI
高影响因子
Science China-Materials
·
2020
·Vol. 64
·期 5
·1150-1158
·
IF 6.098
Chen Jing,Pan Anqiang,Zhang Wenchao,Cao Xinxin,Lu Rou,Liang Shuquan,Cao Guozhong
Noble metal-free electrocatalysts with high activity are highly desirable for the large-scale application of hydrogen evolution reaction (HER). Mo 2 C-based nanomaterials have been proved as a promising alternative to noble metal-based electrocatalysts owing to the Pt-resembled d-band density and optimal intermediates-adsorption properties. However, the aggregation and excessive growth of crystals often occur during their high-temperature synthesis procedure, leading to low catalytic utilization. In this study, the ultrafine Mo 2 C/Mo 2 N heterostructure with large surface and interface confined in the N-doped carbon nanofibers (N-CNFs) was obtained by a melamine-assisted method. The synergistic effect of Mo 2 C/Mo 2 N heterostructure and plenty active sites exposed on the surface of ultrafine nanocrystals improves the electrocatalytic activity. Meanwhile, the N-CNFs ensure fast charge transfer and high structural stability during reactions. Moreover, the in-situ synthesis method strengthens the interfacial coupling interactions between Mo 2 C/Mo 2 N heterostructure and N-CNFs, further enhancing the electronic conductivity and electrocatalytic activity. Owing to these advantages, Mo 2 C/Mo 2 N@N-CNFs exhibit excellent HER performance with a low overpotential of 75 mV at a current density of 10 mV cm −2 in alkaline solution, superior to the single phased Mo 2 C counterpart and recently reported Mo 2 C/Mo 2 N based catalysts. This study highlights a new effective strategy to design efficient electrocatalysts via integrating heterostructure, nanostructure and carbon modification.
研究领域:
材料科学
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电化学
·
纳米技术
·
能量转换
·
催化
✓ 已验证
DOI
高影响因子
Nanomaterials
·
2024
·Vol. 14
·期 3
·243
·
IF 4.4
Zhaofeng Zhai,Chuyan Zhang,Bin Chen,Lusheng Liu,Haozhe Song,Bing Yang,Ziwen Zheng,Junyao Li,Xin Jiang,Nan Huang
Developing non-precious metal-based electrocatalysts operating in high-current densities is highly demanded for the industry-level electrochemical hydrogen evolution reaction (HER). Here, we report the facile preparation of binder-free Mo2C-Mo2N heterostructures on carbon nanowalls/diamond (CNWs/D) via ultrasonic soaking followed by an annealing treatment. The experimental investigations and density functional theory calculations reveal the downshift of the d-band center caused by the heterojunction between Mo2C/Mo2N triggering highly active interfacial sites with a nearly zero ∆GH*value. Furthermore, the 3D-networked CNWs/D, as the current collector, features high electrical conductivity and large surface area, greatly boosting the electron transfer rate of HER occurring on the interfacial sites of Mo2C-Mo2N. Consequently, the self-supporting Mo2C-Mo2N@CNWs/D exhibits significantly low overpotentials of 137.8 and 194.4 mV at high current densities of 500 and 1000 mA/cm2, respectively, in an alkaline solution, which far surpass the benchmark Pt/C (228.5 and 359.3 mV) and are superior to most transition-metal-based materials. This work presents a cost-effective and high-efficiency non-precious metal-based electrocatalyst candidate for the electrochemical hydrogen production industry.Keywords:hydrogen evolution reaction;high current density;carbon nanowalls;diamond;Mo2C;Mo2N;heterostructure
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Xiaozhen Chen,Ji Qi,Pan Wang,Chuang Li,Xiao Chen,Changhai Liang
Herein, PVA-Mo 2 C/Mo 2 N nanospheres with surface roughness are synthesized via a polyvinyl alcohol (PVA) involved approach and used for hydrogen evolution reaction (HER). The average crystallite size of the PVA protected nMo 2 CN nanospheres (6.1 nm) is one third of that of the PVA-Mo 2 C/Mo 2 N without PVA protection (17.9 nm). At 10 mA cm −2 current density, the as-synthesized PVA-Mo 2 C/Mo 2 N nanospheres with surface roughness exhibit HER overpotentials of 132 mV and 142 mV with corresponding Tafel slope of 51.8 mV dec −1 and 50.4 mV dec −1 in acid and alkaline medium, respectively. This high apparent activity can be attributed to the high intrinsic activity originated from the adjacent surface active sites of Mo 2 C and Mo 2 N as well as the large ECSA of PVA-Mo 2 C/Mo 2 N nanospheres with surface roughness.
研究领域:
材料科学
·
电化学
·
纳米催化
·
能源化学
·
表面科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）