Mo2C@C nanofibers film as durable self-supported electrode for efficient electrocatalytic hydrogen evolution

2022 ◽  
Author(s):  
Mize Ouyang ◽  
liping zhao ◽  
Jing Liu ◽  
Peng Zhang

Abstract Self-supported electrocatalytic thin films consist 3D conducting network and well-embedded electrocatalysts, which endows the advantage in mass flow kinetics and durability for large-scale water splitting. Synthesis of such self-supported electrode still remains a big challenge due to the difficulty in the control over the 3D conducting network and the simultaneous growth of catalyst with well attachment on the conducting fibers. Herein, a self-supported Mo2C@carbon nanofibers (Mo2C@C NF) film has been successfully fabricated with outstanding electrocatalytic performance under optimized pyrolysis temperature and precursors mass ratio conditions. During the carbonation process, the Mo2C nanoparticles (~16 nm) are simultaneously grown and well dispersed on the inter-connected carbon nanofibers, which form 3D conducting network. The as-formed 3D carbon network is strong enough to support direct electrocatalytic application without additional ink or supporting substrates. This particular electrode structure facilitates easy access to the active catalytic sites, electron transfer, and hydrogen diffusion, resulting in the high hydrogen evolution reaction (HER) activity. A low overpotential of 86 mV is needed to achieve 10 mA cm-2 current density with outstanding kinetics metric (Tafel 43 mV dec-1) in 1M KOH. Additionally, the self-supported Mo2C@C NF film, a binder-free electrode, exhibits extraordinary stability of more than 340 h.

Author(s):  
Kokougan Allado ◽  
Mengxin Liu ◽  
Anitha Jayapalan ◽  
Durga Arvapalli ◽  
Kyle Nowlin ◽  
...  

2021 ◽  
Author(s):  
Weishi Gu ◽  
Zhongqin Pan ◽  
Han Tao ◽  
Yanling Guo ◽  
Jun Pu ◽  
...  

Taking advantage of micro/nano structure engineering and surface boron modulation, we developed a binder-free and support-free electrode to enrich and optimize active sites of Ni.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xuehua Wang ◽  
Xianghu Wang ◽  
Jianfeng Huang ◽  
Shaoxiang Li ◽  
Alan Meng ◽  
...  

AbstractConstruction of Z-scheme heterostructure is of great significance for realizing efficient photocatalytic water splitting. However, the conscious modulation of Z-scheme charge transfer is still a great challenge. Herein, interfacial Mo-S bond and internal electric field modulated Z-scheme heterostructure composed by sulfur vacancies-rich ZnIn2S4 and MoSe2 was rationally fabricated for efficient photocatalytic hydrogen evolution. Systematic investigations reveal that Mo-S bond and internal electric field induce the Z-scheme charge transfer mechanism as confirmed by the surface photovoltage spectra, DMPO spin-trapping electron paramagnetic resonance spectra and density functional theory calculations. Under the intense synergy among the Mo-S bond, internal electric field and S-vacancies, the optimized photocatalyst exhibits high hydrogen evolution rate of 63.21 mmol∙g−1·h−1 with an apparent quantum yield of 76.48% at 420 nm monochromatic light, which is about 18.8-fold of the pristine ZIS. This work affords a useful inspiration on consciously modulating Z-scheme charge transfer by atomic-level interface control and internal electric field to signally promote the photocatalytic performance.


2021 ◽  
Vol 868 ◽  
pp. 159172
Author(s):  
Jibiao Guan ◽  
Yuanjian Liu ◽  
Yini Fang ◽  
Xiangheng Du ◽  
Yaqin Fu ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
L. Orr ◽  
S. C. Chapman ◽  
J. W. Gjerloev ◽  
W. Guo

AbstractGeomagnetic substorms are a global magnetospheric reconfiguration, during which energy is abruptly transported to the ionosphere. Central to this are the auroral electrojets, large-scale ionospheric currents that are part of a larger three-dimensional system, the substorm current wedge. Many, often conflicting, magnetospheric reconfiguration scenarios have been proposed to describe the substorm current wedge evolution and structure. SuperMAG is a worldwide collaboration providing easy access to ground based magnetometer data. Here we show application of techniques from network science to analyze data from 137 SuperMAG ground-based magnetometers. We calculate a time-varying directed network and perform community detection on the network, identifying locally dense groups of connections. Analysis of 41 substorms exhibit robust structural change from many small, uncorrelated current systems before substorm onset, to a large spatially-extended coherent system, approximately 10 minutes after onset. We interpret this as strong indication that the auroral electrojet system during substorm expansions is inherently a large-scale phenomenon and is not solely due to many meso-scale wedgelets.


2017 ◽  
Vol 5 (25) ◽  
pp. 13196-13203 ◽  
Author(s):  
Bowen Ren ◽  
Dongqi Li ◽  
Qiuyan Jin ◽  
Hao Cui ◽  
Chengxin Wang

Novel 3D porous tungsten carbide hybrid nanowires (p-WCx NWs) are prepared on carbon cloth as a binder-free efficient electrocatalyst for hydrogen evolution. It shows a high activity and outstanding stability in both acidic and alkaline solutions.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Sahebali Manafi ◽  
Mohammad Reza Rahimipour ◽  
Iman Mobasherpour ◽  
Atefeh Soltanmoradi

Mechanothermal (MT) method is one of the methods used for large-scale production of carbon nanotubes/nanofibers. The different peculiar morphologies of carbon allotropes are introduced with an extraordinary structure for the first time by MT method. In this paper, the influence of milling time and annealing temperature on the crystallinity and morphology of the synthesized nanopowders was investigated. Surprisingly, in this investigation, we report the synthesis of springlike multiwalled carbon nanofibers (S-MWCNFs) by a two-step annealing of milled graphite in an Ar atmosphere. On the other hand, the MT method could be used for the preparation of suitable structures with applications in nanocomposite materials, which is an important task in the era of nanotechnology.


2021 ◽  
Author(s):  
Xunliang Hu ◽  
Irshad Hussain ◽  
Bien Tan

Abstract Covalent triazine frameworks (CTFs) have recently been demonstrated as promising materials for photocatalytic water splitting and are usually used in the form of suspended powder. From a practical point of view, immobilized CTFs materials are more suitable for large-scale water splitting applications, owing to their convenient separation and recycling potential. However, existing synthetic approaches mainly result in insoluble and unprocessable powders, which makes their future device application still a huge challenge. Herein, we report an aliphatic amine-assisted interfacial polymerization method to obtain free-standing, crystalline CTFs film with excellent photoelectric performance. The lateral size of the film was up to 250 cm2, the average thickness can be regulated from 30-500 nm. The crystalline structure was confirmed by high-resolution transmission electron microscope (HR-TEM), powder X-ray diffraction (PXRD), and small-angle X-ray scattering (SAXS) analysis. Intrigued by the good light absorption, crystalline structure, and big lateral size of the film, it was immobilized on a glass support that exhibited good photocatalytic hydrogen evolution performance (5.4 mmol h-1 m-2) and was easy to recycle.


Author(s):  
Zongyun Mu ◽  
Ting Guo ◽  
Hao Fei ◽  
Dingsheng Xu ◽  
Yaoqing Mao ◽  
...  

Molybdenum carbide (Mo2C) has received great attention as a promising non-noble metal electrocatalyst for hydrogen evolution reaction (HER). The exposure of more catalytic sites and optimal Mo-H bonding strength via...


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