Energy Storage Materials
·
2021
·
IF 17.789
Xiaowei Mu,Chao Xia,Bin Gao,Shuyi Guo,Xueping Zhang,Jianping He,Yonggang Wang,Hao Dong,Ping He,Haoshen Zhou
Rechargeable Li-O 2 batteries have captured increasing attention owing to their ultra-high theoretical specific energy. However, this promising system is confronted with the large overpotential, limited discharge capacity and low cyclic life. Herein, three two-dimensional (2D) molybdenum-based compounds of MoN, MoO 3 and MoS 2 are used as cathode catalysts in Li-O 2 batteries . The catalytic performance and electronic structures of these catalysts are compared comprehensively. Electrochemical test results reveal the superior battery performance of MoN cathodes, which deliver the highest specific discharge capacity of approximately 7400 mAh g − 1 and the lowest discharge/charge overpotential of 0.19/0.72 V. Density functional theory (DFT) calculations demonstrate the metallic property of MoN whereas MoO 3 and MoS 2 are poor conductive. Besides, interface properties between MoN and Li 2 O 2 products as well as reaction pathways of the Li-O 2 battery with MoN cathode are also investigated detailedly by DFT calculations, explaining the excellent catalytic properties of MoN at the atomic level. The present work provides intrinsic insights into designing high-performance cathode catalysts for Li-O 2 batteries with fine-tuned morphology and electronic characteristics.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2020
·
IF 4.939
Man Zhao,Xiaofang Ma,Siwei Yan,He Xiao,Ya Li,Tianjun Hu,Zhanfeng Zheng,Jianfeng Jia,Haishun Wu
Activating the inert basal planes of layered molybdenum disulfide (MoS 2 ) is critical to deliver its high hydrogen evolution reaction (HER) efficiency. Herein, oxygen-incorparated MoS x with abundant undercoordinated Mo atoms is fabricated by a facile solvothermal procedure, which realizes synergistically structural and electronic regulations of MoS 2 inert basal planes . Experiment results reveal that oxygen incoparation can effectively modulate the electronic structure and further optimize the intrinsic conductivity, while the defect-rich structure with abundant undercoordinated Mo atoms increases the number of active sites. Moreover, the influence of solvothermal temperature on activity of MoS 2-x is also investigated. The achieved MoS x electrocatalyst prepared at 220 °C exhibits a superior activity for HER with a low overpotential of 191 mV at 10 mA cm −2 , a small Tafel slope of 67 mV dec −1 , and an excellent stability due to the largest surface area and superior conductivity.
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JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Bo Sheng,Xin Zhou,Zhun Shi,Zhaohui Wang,Yaoguang Guo,Xiaoyi Lou,Jianshe Liu
The interaction of reductive metal ions and peroxymonosulfate (PMS) is necessary for the generation of sulfate radials (SO 4 − ), however, this process is greatly restrained by the sluggish reduction of high-valent metal ions. Here we report that commercially available reductive metal (Mo or W) powders are capable of unlocking this kinetic constraint. The reduction of Fe(III) to Fe(II), decomposition of PMS, and degradation/mineralization of 4-chlorophenol (4-CP) are all accelerated in the Mo/Fe 2+ /PMS process at a very low Fe 2+ /PMS ratio (Fe 2+ /PMS = 1/10). In such an accelerated system, common adverse effects of natural water constituents such as chloride and humic acid are largely mitigated. According to the fluorescence measurement and scavenging tests, sulfate and hydroxyl radicals dominate in Mo/Fe 2+ /PMS process. The addition of Mo or W is further confirmed to favor Cu 2+ /PMS process, but this is not the case for other metal ions (Mn 2+ , Ni 2+ , Ce 3+ and Co 2+ ). Reductive zero-valence and four-valence active sites (Mo 0 and Mo 4+ ; W 0 and W 4+ ) play key roles in overall redox reaction. Overall, our present work provides an alternative route for expediting redox cycling of transition metals in advanced oxidation processes, without useless consumption of PMS and increase of total organic carbon.
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高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Liang Cheng,Biaojie Yan,Rui Gao,Xiangdong Liu,Zhenliang Yang,Bingqing Li,Yi Zhong,Pengchuang Liu,Yun Wang,Mingfu Chu,Bin Bai,Pengcheng Zhang
UO 2 /Mo composite pellets with enhanced thermal conductivity have been considered for the novel construction of high-safety fuel systems. UO 2 /Mo core-shell composite pellets with a reasonable porosity of 4–5% were fabricated by spark plasma sintering (SPS). In the SPS UO 2 /Mo composite, the majority of pores remained homogeneous in the UO 2 matrix, while it had a dense morphology in the continuous Mo channel for the heat conduction . The sintering behaviour of the UO 2 /Mo composite indicated that the incorporating Mo impeded densification of UO 2 , and the primary densification temperature ranged from 903 K to 1270 K. To introduce 2 vol% Mo to UO 2 , the thermal conductivity (TC) was enhanced to 4.02 W/m·K at 1073 K. The above result represented a 23.31% improvement over the value of 3.26 W/m·K (Fink) for a pure UO 2 pellet, which was approximated by the revised Hasselman-Johnson model. In particular, the coefficient of thermal expansion (CTE) was reduced to 10.0 × 10 −6 /K from 298 K to 1673 K, representing an 8.83% reduction from the value of 10.98 × 10 −6 /K (Martin) for a pure UO 2 pellet. The reduction effect on the CTE was superior to that of other UO 2 matrix composites fuel systems and, hence, offers an external safety aspect for reactors at the elevated temperatures close to accident conditions. These results provide a feasible method for the fabrication of a UO 2 /Mo core-shell pellet as an accident tolerant fuel.
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Nature Communications
·
2023
·Vol. 14
·期 1
·1-12
·
IF 16.6
Guo Luyao,Zhuge Kaixuan,Yan Siyang,Wang Shiyi,Zhao Jia,Wang Saisai,Qiao Panzhe,Liu Jiaxu,Mou Xiaoling,Zhu Hejun,Zhao Ziang,Yan Li,Lin Ronghe,Ding Yunjie
Supported metal clusters comprising of well-tailored low-nuclearity heteroatoms have great potentials in catalysis owing to the maximized exposure of active sites and metal synergy. However, atomically precise design of these architectures is still challenging for the lack of practical approaches. Here, we report a defect-driven nanostructuring strategy through combining defect engineering of nitrogen-doped carbons and sequential metal depositions to prepare a series of Pt and Mo ensembles ranging from single atoms to sub-nanoclusters. When applied in continuous gas-phase decomposition of formic acid, the low-nuclearity ensembles with unique Pt 3 Mo 1 N 3 configuration deliver high-purity hydrogen at full conversion with unexpected high activity of 0.62 mol HCOOH mol Pt −1 s −1 and remarkable stability, significantly outperforming the previously reported catalysts. The remarkable performance is rationalized by a joint operando dual-beam Fourier transformed infrared spectroscopy and density functional theory modeling study, pointing to the Pt-Mo synergy in creating a new reaction path for consecutive HCOOH dissociations.
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APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Jianjun Zhu,Huamei Tong,Yu Liu,Jiahui Hu,Xinyu Zheng,Mengyue Qi,Deli Jiang
Exploring integrated regulation strategies to boosting electrocatalytic performance is essential to design more efficient and inexpensive OER catalysts. Herein, amorphous and crystalline (a-c) interface engineering and heteroatom doping are integrated to construct a novel electrocatalyst containing amorphous FeSeO x and crystalline Mo-doped NiSe 2 (denoted as FeSeO x /Mo-NiSe 2 ) via pseudocrystalline replication method and selenization treatment. The resultant FeSeO x /Mo-NiSe 2 electrocatalyst with 3D hierarchical nanoarchitectures of nanorod arrays covered by interlocking nanoblocks exposes more active sites and accelerated reaction kinetics. Furthermore, a-c interface engineering and heteroatom doping can synergistically enhance the intrinsic activity and charge transfer capability of NiSe 2 by decreasing the electron diffusion distance and flexibly modulating the electronic structure, which contributes to boost the oxygen evolution reaction (OER) performance. Consequently, the obtained FeSeO x /Mo-NiSe 2 achieves a low overpotential of 205 mV at 10 mA cm −2 , which outperforms many other transitions metal selenides electrocatalysts. Density functional theory (DFT) calculations demonstrate that the formation of an internal electric field between FeSeO x and Mo-NiSe 2 accelerates charge transport and optimizes the adsorption/desorption of oxygen-containing intermediates, thereby accelerating the reaction kinetics and improving the OER performance. This work serves as a point of reference for designing innovative metal selenides based electrocatalysts combining a-c interface engineering and heteroatom doping.
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Carbon Energy
·
2023
·
IF 20.5
Zhichao Jia,Yang Yuan,Yanxing Zhang,Xiang Lyu,Chenhong Liu,Xiaoli Yang,Zhengyu Bai,Haijiang Wang,Lin Yang
Transition-metal oxyhydroxides are attractive catalysts for oxygen evolution reactions (OERs). Further studies for developing transition-metal oxyhydroxide catalysts and understanding their catalytic mechanisms will benefit their quick transition to the next catalysts. Herein, Mo-doped CoOOH was designed as a high-performance model electrocatalyst with durability for 20 h at 10 mA cm −2 . Additionally, it had an overpotential of 260 mV (glassy carbon) or 215 mV (nickel foam), which was 78 mV lower than that of IrO 2 (338 mV). In situ, Raman spectroscopy revealed the transformation process of CoOOH. Calculations using the density functional theory showed that during OER, doped Mo increased the spin-up density of states and shrank the spin-down bandgap of the 3d orbits in the reconstructed CoOOH under the electrochemical activation process, which simultaneously optimized the adsorption and electron conduction of oxygen-related intermediates on Co sites and lowered the OER overpotentials. Our research provides new insights into the methodical planning of the creation of transition-metal oxyhydroxide OER catalysts.
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NANOTECHNOLOGY
·
2023
·Vol. 35
·期 10
·105702
·
IF 3.5
Xuefeng Zhang,Qin Yang,Longcheng Zhang,Jun Li,Shengjun Sun,Yingchun Yang,Yuntong Sun,Xuping Sun
Seawater splitting is a compelling avenue to produce abundant hydrogen, which requires high-performance and cost-effective catalysts. Constructing bimetallic transition metal phosphides is a feasible strategy to meet the challenge. Here, an amorphous Co–Mo–P film supported on nickel foam (Co–Mo–P/NF) electrode is developed with bifunctional properties for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline seawater. Corresponding results indicate that the introduction of Mo can improve the active sites and regulate the intrinsic activity. Such a Co–Mo–P/NF behaves with prominent electrocatalytic activity towards both HER and OER, demanding low overpotentials of 193 and 352 mV at 100 mA cm‒2 in alkaline seawater, respectively. Furthermore, the assembled electrolyzer demands a pronounced overall seawater splitting activity with a low cell voltage of 1.76 V to deliver 100 mA cm−2 presenting excellent durability without obvious attenuation after 24 h continuous stability test. This work expands the horizon to develop transition metal-phosphorus electrocatalysts with robust and efficient activity for overall seawater splitting.
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高影响因子
RARE METALS
·
2023
·Vol. 42
·期 8
·2592-2600
·
IF 8.8
Chen Jing,Chen Xuan-Le,Lu Rou,Li Yong,Pan An-Qiang
Molybdenum dioxide has aroused a wide concern as anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity and high density. However, it still faces the problems of large volume changes and low electronic conductivities, which limits its practical application. Herein, necklace-like N-doped carbon nanofibers encapsulating MoO 2 nanospheres (MoO 2 @NCNFs) with Mo–C bonding have been designed to address these issues. The rational design carbon coating structure can not only enhance the electron transfer, but also markedly strengthen structural stability. As expected, the as-prepared electrode showed superior lithium storage capacity, including a high specific capacity of 1120 mAh·g −1 at 0.1 A·g −1 , and good rate performance of 502 mAh·g −1 at 4.0 A·g −1 and a prolonged cycling stability of 490 mAh·g −1 capacity retention over 3000 cycles at 4.0 A·g −1 . Graphical abstract
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SENSORS AND ACTUATORS B-CHEMICAL
·
2023
·
IF 8.4
Heming Sun,Xiaonian Tang,Shuo Li,Ye Yao,Li Liu
The construction of the materials with one-dimensional (1D) hollow structure using Metal-organic frameworks (MOFs) as the templates has attracted much attention for applied in various fields. Herein, MOF-derived 1D Ru/Mo co-doped Co 3 O 4 hollow microtubes have been obtained via a simple solvothermal method . The as-synthesized samples are characterized by using XRD, FESEM , TEM , XPS, PL and BET. The sensing measurement reveals that when doping amount of Mo and Ru is 1% and 0.3%, the Co 3 O 4 sample exhibits the best sensing performance. Specially, 0.3% Ru/Mo-Co 3 O 4 sample exhibits high responses of 126–100 ppm TEA at a low operating temperature of 160 °C, which are about 18.5 times than that of pure Co 3 O 4 . Furthermore, it shows rapid response/ recovery speed (5 s/7 s), good selectivity and repeatability as well as excellent long-term stability. The good TEA sensing performance is attributed to the construction of 1D hollow architecture and synergistic effect of Ru/Mo co-doping. Thus, it is expected to be a promising sensing material for high-performance detection of TEA gas. In addition, this work provides an useful inspiration for preparation of MOF-derived materials with 1D hollow architecture for achieving excellent performance in various fields.
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APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Xinyang Dong,Yundong Cao,Jiayuan Zhang,Linlin Fan,Mingliang Wang,Hong Liu,Guanggang Gao
Lithium-sulfur batteries (LSBs) present wide range of market and tremendous application potential. Nevertheless, the “shuttle effect” of lithium polysulfides (LiPSs) and the sluggish redox kinetics restrict their large-scale application. We report herein the Mo-substituted Keggin type H 3 PW 10 Mo 2 O 40 (PW 10 Mo 2 ) evenly decorated on the MWCNTs conductive framework by electrostatic attraction as the functional interlayer materials. W and Mo atoms in PW 10 Mo 2 provide chemical adsorption sites for polysulfides, and density functional theory (DFT) calculations further confirm that Mo sites possess stronger capture ability to LiPSs than that of W sites. Meanwhile, the Mo implantation can effectively expedite the redox reaction of LiPSs. Furthermore, MWCNTs afford the plentiful attachment points for PW 10 Mo 2 , thus exposing abundant active sites to adsorb and catalyze polysulfides. The resulting cells demonstrate superior discharge capacity of 1064.9 mAh g −1 under 0.2C up to 100 cycles as well as excellent long-life cycling stability with low recession rate of 0.051 % under 3C up to 1000 cycles. Our work illustrates the effect of Mo atom substitution of polyoxotungstates as interlayer materials and thereby provides a new strategy for developing LSBs with superior reversible capacity and long cycling performance.
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ChemElectroChem
·
2023
·Vol. 10
·期 3
·e202201087
·
IF 4
Shaojie Gao,Ping Li,Yao Shi,Yi He,Lecheng Lei,Shaoyun Hao,Xingwang Zhang
Graphical Better with defects : A ternary alloy PtCoMo nanocatalyst with dual surface Co and Mo vacancy defects was used as an efficient electrocatalyst for acidic oxygen reduction reaction for fuel cell applications. Proton exchange membrane fuel cell (PEMFC) is considered as the most promising energy conversion technology, which is hampered by the unsatisfied activity and high loading of Pt. The performance of Pt-based catalyst toward PEMFC depends on the surface bond length of Pt−Pt, which is closely related to the surface defect engineering. Here we firstly present a ternary alloy PtCoMo nanocatalyst with dual surface Co and Mo vacancy defects (V Co−Mo −PtCoMo) that compressed the Pt−Pt bonds, thus exhibiting an outstanding activity toward oxygen reduction reaction (ORR) with a mass activity of 0.57 A mg Pt −1 at 0.9 V (RHE, reversible hydrogen electrode), which is 5.2 times higher as compared with commercial Pt/C (20 wt %) in 0.1 M HClO 4 . The characterizations and density functional theory calculations demonstrate that the Pt−Pt bonds are significantly compressed through the dual surface defects, thus weakening the binding energy and effectively enhancing the acidic ORR performance.
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