DALTON TRANSACTIONS
·
2023
·Vol. 52
·期 9
·2887-2897
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IF 4
Zhifeng He,Xin Cui,Guangping Lei,Zeyi Liu,Xiaoyang Yang,Yifu Liu,Jiafeng Wan,Fangwei Ma
Molybdenum (Mo) is one of the most important constituent elements in natural nitrogenase and theoretical calculation results show that Mo-based materials can be used as potential NRR electrocatalysts. The design of advanced catalysts with a special structure is very essential for promoting the development of electrocatalytic N2 into NH3. In this paper, Fe-doped MoO2/C heterostructured nanoparticles with rich oxygen vacancies (Vo) are designed and they exhibit highly efficient catalytic activity for artificial N2 fixation in neutral electrolytes under ambient conditions. The influence of the atomic ratio of the Fe source to the Mo source and the NaBH4 ethanol solution treatment on the structure and electrocatalytic performance are systematically investigated. The Vo-Fe–MoO2/C (1 : 50) catalyst with rich oxygen vacancies shows a satisfactory electrocatalytic N2 reduction reaction (e-NRR) activity in 0.1 M Na2SO4 with a high ammonia yield rate of 15.87 ± 0.3 μg h−1 mg−1 at −0.5 V versus the reversible hydrogen electrode (vs. the RHE) and a FE of 13.4% at −0.3 V (vs. the RHE). According to the results of DFT calculations, the active center of the electro-catalytic nitrogen reduction reaction is the molybdenum atom between the iron atom and the O vacancy. Oxygen vacancies can not only reduce the energy barrier of the RDS but also facilitate the desorption of ammonia and the first step hydrogenation of nitrogen. The doping of Fe will change the electronic state of the Mo atom in MoO2.
研究领域:
材料科学
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电化学
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理论计算
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Ling Zhang,Xijian Liu,Min Zhang,Haikuan Yuan,Lijuan Zhang,Jie Lu
We present here a novel, simple, low cost and green synthetic strategy for unique core-shell structured Fe 3 O 4 @C-MoO 2 -Ni composites without using extra reducing agent. The Fe 3 O 4 @C-MoO 2 -Ni composites exhibited better catalytic performance (reduction of 4-nitrophenol to 4-aminophenol) than previous common catalysts because highly dense satellite Ni nanoparticles firmly distributed on the porous carbon spheres. In addition, the Fe 3 O 4 @C-MoO 2 -Ni composites can be used as a pollutant remover due to fast adsorption rate and high adsorption capacity for dye in water. More importantly, owing to high magnetic susceptibility , the Fe 3 O 4 @C-MoO 2 -Ni composites show excellent performance for recyclable use by magnetic separation. Thus, the Fe 3 O 4 @C-MoO 2 -Ni composites have great potential as an ideal catalyst and adsorbent due to facile and green synthesis method, good stability, excellent recyclability, nontoxic and low cost properties.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Shaobin Li,Jingwei Liang,Xiaoguo Tan,Fengbo Li,Xinming Wang,Lin Ma,Li Zhang,Kun Cheng
Electrochemical water splitting is regarded as a promising technology for production of high purity, high volume hydrogen. It is critical to create robust and highly active electrocatalysts in order to minimize the cost of hydrogen generation and enable large-scale commercial production. In this work, a new 2D MoCu-POMOF, [Cu(4-pyz)] 4 @(PMo 12 O 40 ) (4-pyz = 4-(pyridin-4-yl)benzoic acid) was prepared by a simple hydrothermal method , in which PMo 12 nanocluster was encapsulated into cavity of 2D Cu-MOF. The successful establishment of the model in addition to the goal of uniformly dispersed Mo sources target oxygen-rich PMo 12 nanoclusters can also provide rich Mo source and self-oxidative properties for MoO 2 formation. Cu-MOF provides a special layered structure, which ensures the integrity and stability of the structure and provides a rich C source for pyrolysis and improves the conductivity. Ultralow Pt nanoparticles can reduce free energy of hydrogen evolution , which are embedded in MoO 2 /MoOC with porous structure and high electrochemical active surface area . MoO 2 /MoOC and highly dispersed Pt nanoparticles synergistically promote the HER catalysis. Pt@MoO 2 /MoOC demonstrated the excellent HER activity with a low overpotential of 98.99 mV vs. RHE. This work yielded highly active and high stability molybdenum-based HER electrocatalysis and provides the potential for energy conversion.
研究领域:
材料科学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Nano
·
2021
·
IF 15.881
Yuchi Wan,Zhijie Wang,Jia Li,Ruitao Lv
The electrocatalytic nitrogen reduction reaction (NRR) has been regarded as a promising strategy for producing ammonia (NH3) at ambient conditions. However, the development of the NRR is severely hindered by the difficult adsorption and activation of N2 on the catalyst surface and the competitive hydrogen evolution reaction (HER) due to the lack of efficient NRR electrocatalysts. Herein, Mo2C-MoO2 heterostructure quantum dots embedded in reduced graphene oxide (RGO) are proposed as efficient catalysts for the electrocatalytic NRR. The ultrasmall size of the quantum dot is beneficial for exposing the active sites for the NRR, and the synergetic effect of Mo2C and MoO2 can promote N2 adsorption and activation and suppress the competitive HER simultaneously. As a result, a well-balanced NRR performance is achieved with a high NH3 yield rate of 13.94 ± 0.39 μg h–1 mg–1 at −0.15 V vs RHE and a high Faradaic efficiency of 12.72 ± 0.58% at −0.1 V vs RHE. Density functional theory (DFT) calculations reveal that the Mo2C (001) surface has a strong N2 adsorption energy of −1.47 eV with the side-on configuration, and the N≡N bond length is elongated to 1.254 Å, indicating the enhanced N2 adsorption and activation on the Mo2C surface. On the other hand, the low ΔGH* for HER over the MoO2 (−111) surface demonstrates the impeded HER process for MoO2. This work may provide effective catalyst-design strategies for enhancing the electrocatalytic NRR performance of Mo-based materials.
研究领域:
材料科学
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电化学
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理论计算
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Advanced Ceramics
·
2022
·Vol. 11
·期 9
·1431-1444
·
IF 11.534
Jin Sen,Jing Huijuan,Wang Libo,Hu Qianku,Zhou Aiguo
Nowadays, photocatalytic technologies are regarded as promising strategies to solve energy problems, and various photocatalysts have been synthesized and explored. In this paper, a novel CdS/MoO 2 @Mo 2 C-MXene photocatalyst for H 2 production was constructed by a two-step hydrothermal method, where MoO 2 @Mo 2 C-MXene acted as a binary co-catalyst. In the first hydrothermal step, MoO 2 crystals with an egged shape grew on the surface of two-dimensional (2D) Mo 2 C MXene via an oxidation process in HCl aqueous solution. In the second hydrothermal step, CdS nanorods were uniformly assembled on the surface of MoO 2 @Mo 2 C-MXene in ethylenediamine with an inorganic cadmium source and organic sulfur source. The CdS/MoO 2 @Mo 2 C-MXene composite with MoO 2 @Mo 2 C-MXene of 5 wt% exhibits an ultrahigh visible-light photocatalytic H 2 production activity of 22,672 µmol/(g·h), which is ∼21% higher than that of CdS/Mo 2 C-MXene. In the CdS/MoO 2 @Mo 2 C-MXene composite, the MoO 2 with metallic nature separates CdS and Mo 2 C MXene, which acts as an electron-transport bridge between CdS and Mo 2 C MXene to accelerate the photoinduced electron transferring. Moreover, the energy band structure of CdS was changed by MoO 2 @Mo 2 C-MXene to suppress the recombination of photogenerated carriers. This novel compound delivers upgraded photocatalytic H 2 evolution performance and a new pathway of preparing the low-cost photocatalyst to solve energy problems in the future.
研究领域:
材料科学
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2024
·
IF 5.3
Xuan Liu,Xiaoxiao Lu,Luying Li,Chi Chen,Zhao Xu,Yang Xia
Inspired by beds of silkworm cocoon, a flexible ″plane-wire″ MoO 2 -anchored carbon nanofiber matrix has been successfully prepared through electrospinning and subsequent annealing processes. It delivers an initial discharge capacity of 877 mAh g − 1 at 200 mA g − 1 with a high initial coulombic efficiency of 84.7 % and showcases a high reversible specific capacity of 743 mAh g − 1 in the second cycle when employed as free-standing anodes for lithium batteries. It also exhibits good rate performance and superb cyclability, which delivering a specific capacity of 364 mAh g − 1 at a high current density of 2 A g − 1 and maintains a notable specific capacity of 674 mAh g − 1 even after 2000 cycles. It is found that, the carbon nanofiber matrix serves as a robust electronic conductive network to reduce the charge transfer resistance and promote the transportation of Li + , and provides excellent support to buffer volume changes of the MoO 2 , resulting in enhanced rate performance and cyclability. Moreover, these electrodes are designed to be free-standing, which can improve the flexibility of the electrode and initial coulombic efficiency. It is believed that the as-prepared ″plane-wire″ MoO 2 -anchored carbon nanofiber matrix is a promising anode material for high-performance LIBs.
研究领域:
材料科学
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能源存储
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Da Ouyang,Ronghao Wu,Zhaojun Xu,Xiaomin Zhu,Yimin Cai,Ruihuan Chen,Changyin Zhu,Damià Barceló,Haibo Zhang
Advanced oxidation processes (AOPs) based on persulfate (PDS) activation by iron materials have attracted significant attention due to their high organic pollution removal efficiency and relatively low remediation costs. However, one of the iron-based materials’ shortcomings is the weak activation ability of Fe 3+ on PDS and the low sustainability of Fe 2+ in the oxidation environment. In this study, biochar-supported molybdenum dioxide (MoO 2 @BC) was employed as a co-catalyst to enhance the Fe 3+ based PDS activation for Bisphenol A (BPA) degradation. Results showed that >96 % of BPA was removed during 60 min, and the BPA degradation efficiencies only slightly decreased after four reuses of MoO 2 @BC. Electron paramagnetic resonance (EPR) analysis and quenching experiments indicated that reactive oxidation species (ROSs) contributing to the degradation of BPA were SO 4 − , OH and 1 O 2 . Besides, it was found that biochar supporting favours the adsorption of Fe 3+ on the MoO 2 surface and promotes the electron transfer from Mo(IV) to Fe 3+ based on the combination of X-ray photoelectron spectroscopy (XPS) analysis, electrochemical tests and density functional theory calculation (DFT). This work provides a new insight for enhancing the performance of organic contaminants degradation through AOPs based on persulfate activation by iron material.
研究领域:
环境科学
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化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Qiuyan Hao,Guoliang Cui,Yongguang Zhang,Jingde Li,Zisheng Zhang
Despite their high theoretical capacity (1672 mAh g −1 ) and energy density (2600 Wh kg −1 ), the commercialization of lithium/sulfur (Li/S) batteries is hindered by the polysulfide shuttle phenomenon and sluggish electrode kinetics. Herein, we demonstrate a novel MoSe 2 /MoO 2 heterostructure via water-steam etching as an effective sulfur host for high-performance Li/S batteries. The as-prepared flower-like MoSe 2 /MoO 2 heterostructure exhibited strong affinity toward polysulfide intermediates with a strong adsorption energy of −3.46 eV, rendered by MoO 2 , and enhanced the redox kinetics significantly. Consequently, S/MoSe 2 /MoO 2 electrode, with 66% sulfur content, delivered a high initial capacity of 1100 mAh g −1 and high capacity retention of 77.1% after 500 cycles at 0.5 C. The synthesis of MoSe 2 /MoO 2 heterostructure presents a promising strategy to design sulfur hosts for high-performance Li/S batteries.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Xiao Yang,Rong Qiang,Yulong Shao,Fangjie Ren,Lei Rong,Jingbo Fang,Rui Xue,Zihan Liu
With the advancement of modern electronic communication technology, the development of efficient absorbing materials has attracted great interest. Here, hollow hydrangea-like Mo 2 C/MoO 2 /C composites are synthesized by soft template method. By adjusting the pyrolysis temperature, Mo 2 C/MoO 2 /C composites with different Mo 2 C and MoO 2 contents and degrees of graphitization can be selectively synthesized. The Mo 2 C/MoO 2 /C-800 composite with the 30 wt% filler content exhibits a minimum reflection loss of −62.9 dB at 1.6 mm and achieves a maximum absorption bandwidth of 6.2 GHz at 1.9 mm. The interaction between the dielectric properties of each component and the unique 3D hydrangea-like structure promotes microwave absorption and dissipation. Besides, CST simulation further demonstrates the effectiveness of electromagnetic wave dissipation in practical applications. The excellent properties of the hydrangea-like Mo 2 C/MoO 2 /C composites indicate their promising applications in electromagnetic wave absorbers.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Yun-Liang Dai,Ao-Ping Guo,Mei-Hua Gong,Xiao-Juan Zhang,Bian-Ying Wen
Exploring highly efficient electromagnetic interference (EMI) shielding filler is urgently desired for next-generation wireless communication and integrated electronics. In this regard, a series of heterogeneous MoO 2 / N -doped carbon (MoO 2 /NC) nanorods with tunable conductivity have been successfully synthesized by regulating the pyrolysis temperature within 600, 700 and 800 °C. Profiting from the rational design of heterointerface and low-dimensional structure, the MoO 2 /NC powder achieves stronger EMI shielding capacity with the incremental temperature. It is found that the MoO 2 /NC-800 nanorods exhibit the optimal average EMI shielding effectiveness (SE) of 57.2 dB at a thickness of ∼0.3 mm in the X band. Meanwhile, the corresponding shielding mechanisms of MoO 2 /NC nanorods are also elaborately explained. More interestingly, the increase of sintering temperature makes an obvious effect on absorption loss but has little influence on reflection loss, demonstrating that adjusting the pyrolysis temperature is an effective strategy to strengthen the electromagnetic energy dissipation.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Yu Qiu,Shuangquan Liu,Cong Wei,Jianxiong Fan,Hu Yao,Lanxin Dai,Gongming Wang,Hong Li,Baolian Su,XiaoHui Guo
Single-atomic or cluster-based precious metals provide an effective pathway to minimize the cost of catalysts. However, its stability at large current density is still a major hurdle to satisfy practical requirements for electrocatalytic Hydrogen evolution reaction (HER). Herein, we successfully anchored Pt single atoms (Pt SAs) in the oxygen vacancies (O vac ) of Molybdenum dioxide (MoO 2 ) as advanced HER electrocatalyst. Experimental and theoretical calculations results reveal that the O vac can not only stabilize Pt SAs, but also modulate the electronic structure of the active site, enabling Pt SAs/MoO 2 to exhibit superior HER activity in a wide pH electrolyte at large current density. Especially, the 1.1 wt% Pt SAs/MoO 2 deliver ultralow overpotentials (9.3, 14, and 16 mV at 10 mA cm −2 ) and small Tafel slopes (28.78, 36.86, and 65.18 mV dec -1 ) in acidic, alkaline, and neutral electrolytes, respectively. Moreover, it displays significantly enhanced mass activity of up to 28, 32, and 56 times compared to the benchmark 20 wt% Pt/C catalyst, and outstanding long-term durability (~200 h) at large current density of −1000 mA cm −2 . The significantly improved HER performances are mainly ascribed to the synergistic catalytic effects of between Pt SAs and O vac in MoO 2 . These impressive findings can provide insights into the rational design of electrocatalysts that used for future clean energy utilization.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Xinyu Wang,Shiqi Chen,Can Liu,Jiapeng Yue,Zhiwei Yang,Qian Ye,Hao Xu,Yujian Zhang,Xinyi Xing,Jing Zhang
In this study, the charge transfer capability of MoO 2 materials was significantly improved by introducing carbon materials in situ. The resulting MoO 2 -C material could accelerate the Fe(III)/Fe(II) redox cycle and promote the continuous generation of reactive oxygen species in Fenton-like system. The results suggested that MoO 2 -C exhibited significant co-catalytic activity against a variety of pollutants. Meanwhile, the mechanisms behind the Fe(III)/Fe(II) cycle and reactive oxygen species generation were clarified. Analysis indicated that the incorporation of carbon material provided a reduction active site for the reduction of Fe(III) to Fe(II) on the surface of molybdenum oxide, and also reduced the thermodynamic energy barrier associated with Fe(III) reduction. Furthermore, quenching experiments and electron paramagnetic resonance (EPR) technology demonstrated that hydroxyl radicals ( ∙ O H ) and singlet oxygen ( 1 O 2 ) rapidly degrade the target pollutants. Fe(II) was verified as the primary component responsible for peroxymonosulfate (PMS) and peroxydisulfate (PDS) activation. Additionally, the main generation pathway for 1 O 2 differed between the MoO 2 -C/Fe(III)/PDS and MoO 2 -C/Fe(III)/PMS systems. This study provides a new strategy to improve the iron reduction properties of metal oxide materials.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）