scholarly journals Construction of Ni-Mo-P heterostructures with efficient hydrogen evolution performance under acidic condition

2021 ◽  
Author(s):  
Tian-Yun Chen ◽  
Ya-Qi Zhang ◽  
Ying-Yan Fu ◽  
Min Qian ◽  
Hao-Jiang Dai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
Large Scale ◽  
Clean Energy ◽  
Hydrogen Energy ◽  
Durability Test ◽  
X Ray ◽  
Onset Potential

Abstract Hydrogen energy is regarded as one of the most important clean energy in the 21st century, and improving the catalytic efficiency of hydrogen evolution reaction (HER) is the basis for realizing the large-scale hydrogen production. Transition metal phosphides (TMPs) were proved to be efficient electrocatalysts for HER. In this work, we first synthesized the nickel-molybdenum bimetallic precursors, followed by high-temperature calcination in air. Finally, NiMoP/MoP nanorods (Ni-Mo-P NRs) was obtained by chemical vapor deposition (CVD) of phosphating. The target catalyst of Ni-Mo-P NRs was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). For Ni-Mo-P NRs, the electrochemical test in 0.5 M H2SO4 solution for HER showed that the optimal feeding ratio was Ni: Mo = 1:1. And the Ni1-Mo1-P NRs presented an onset potential of 63.2 mV, and an overpotential of 117.9 mV was required to drive the current density of 10 mA↔cm− 2. Meanwhile, The Tafel slope, exchange current density (j0), electrochemical double-layer capacitance (Cdl) were 58.6 mV↔dec− 1, 0.10 mA↔cm− 2, 12.6 mF↔cm− 2, respectively. Moreover, there was no obvious activity diminish of Ni1-Mo1-P NRs after a long-term stability and durability test.

Synthesis of the rod-like NiS2@C for hydrogen evolution reaction in acidic solution

2020 ◽  
Vol 13 (02) ◽  
pp. 2050009
Author(s):  
Xiujuan Wu ◽  
Jie Wang ◽  
Fan Zhang ◽  
Junyan Gong ◽  
Pinghao Xu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Photoelectron Spectroscopy ◽  
Acidic Solution ◽  
Carbon Film ◽  
Chemical Deposition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Onset Potential ◽  
Transmission Electron

The carbon-based NiS2 nanorods (NiS2@C) were prepared by chemical deposition and sulfidation with nickel dimethylglyoximate (Ni(DMG)2) as the starting agent. The nanorods were analyzed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy for chemical analysis. Structural characterization revealed that NiS2 existed on the surface of the rod and in the internal channels of the rod. In 0.5[Formula: see text]m H2SO4 solution, NiS2@C has lower onset potential and higher current density than NiS2. The results suggest that C improves the electrical conductivity of the NiS2 electrocatalyst, and the carbon film-based rod-like NiS2 is a more effective nanocomposite of hydrogen evolution.

scholarly journals Amorphous Ni x Co y P-supported TiO2 nanotube arrays as an efficient hydrogen evolution reaction electrocatalyst in acidic solution

2019 ◽  
Vol 10 ◽  
pp. 62-70 ◽  
Author(s):  
Yong Li ◽  
Peng Yang ◽  
Bin Wang ◽  
Zhongqing Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Nanotube Arrays ◽  
Active Surface Area ◽  
X Ray ◽  
Transmission Electron

Bimetallic phosphides have been attracting increasing attention due to their synergistic effect for improving the hydrogen evolution reaction as compared to monometallic phosphides. In this work, NiCoP modified hybrid electrodes were fabricated by a one-step electrodeposition process with TiO2 nanotube arrays (TNAs) as a carrier. X-ray diffraction, transmission electron microscopy, UV–vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy and scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy were used to characterize the physiochemical properties of the samples. The electrochemical performance was investigated by cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. We show that after incorporating Co into Ni–P, the resulting Ni x Co y P/TNAs present enhanced electrocatalytic activity due to the improved electron transfer and increased electrochemically active surface area (ECSA). In 0.5 mol L−1 H2SO4 electrolyte, the Ni x Co y P/TNAs (x = 3.84, y = 0.78) demonstrated an ECSA value of 52.1 mF cm−2, which is 3.8 times that of Ni–P/TNAs (13.7 mF cm−2). In a two-electrode system with a Pt sheet as the anode, the Ni x Co y P/TNAs presented a bath voltage of 1.92 V at 100 mA cm−2, which is an improvment of 79% over that of 1.07 V at 10 mA cm−2.

scholarly journals MOF-Derived CuPt/NC Electrocatalyst for Oxygen Reduction Reaction

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 799 ◽  
Author(s):  
Rehan Anwar ◽  
Naseem Iqbal ◽  
Saadia Hanif ◽  
Tayyaba Noor ◽  
Xuan Shi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Photoelectron Spectroscopy ◽  
Rotating Disk ◽  
Reduction Reaction ◽  
Rotating Disk Electrode ◽  
X Ray ◽  
Onset Potential ◽  
Orr Activity

Metal-organic frameworks (MOFs) have been at the center stage of material science in the recent past because of their structural properties and wide applications in catalysis. MOFs have also been used as hard templates for the preparation of catalysts. In this study, highly active CuPt/NC electrocatalyst was synthesized by pyrolyzing Cu-tpa MOF along with Pt precursor under flowing Ar-H2 atmosphere. The catalyst was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD). Rotating disk electrode study was performed to determine the oxygen reduction reaction (ORR) activity for CuPt/NC in 0.1 M HClO4 at different revolutions per minute (400, 800, 1200, and 1600) and it was also compared with commercial Pt/C catalyst. Further the ORR performance was evaluated by K-L plots and Tafel slope. CuPt/NC shows excellent ORR performance with onset potential of 0.9 V (vs. RHE), which is comparable with commercial Pt/C. The ORR activity of CuPt/NC is demonstrated as an efficient electrocatalyst for fuel cell.

Hydrothermal Synthesis of Few-Layer and Edge-Rich Cobalt-Doped Molybdenum Selenide/Nitrogenated Graphene Composite and Investigation of Its Electrocatalytic Activity for Hydrogen Evolution Reaction

NANO ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. 1650107 ◽  
Author(s):  
Ming Ou ◽  
Lin Ma ◽  
Limei Xu ◽  
Zhuomei Yang ◽  
Haizhen Li
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Photoelectron Spectroscopy ◽  
Hydrothermal Route ◽  
X Ray ◽  
Graphene Composite ◽  
Molybdenum Selenide ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

Cobalt-doped MoSe2/nitrogenated graphene composite has been successfully synthesized via a facile hydrothermal route and is investigated as an electrocatalyst for hydrogen evolution reaction (HER). The as-prepared samples are well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and Raman spectrum. The results reveal that Co-doped MoSe2 nanosheets which are characteristic of few layers (2–4 layers) and abundant exposed active edge sites are well anchored on the nitrogen-doped graphene sheets to constitute robust composites. When evaluated as catalysts for HER, the obtained composites demonstrate superior electrocatalytic activities toward HER.

scholarly journals Facile and Large-scale Synthesis of Defective Black TiO2−x(B) Nanosheets for Efficient Visible-light-driven Photocatalytic Hydrogen Evolution

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1048 ◽  
Author(s):  
JingCheng Xu ◽  
JiaJia Zhang ◽  
ZhengYang Cai ◽  
He Huang ◽  
TianHao Huang ◽  
...  
Keyword(s):  
Visible Light ◽  
Hydrogen Evolution ◽  
Photoelectron Spectroscopy ◽  
Large Scale ◽  
Broad Band ◽  
Mass Ratio ◽  
X Ray ◽  
Black Tio2 ◽  
Large Scale Synthesis ◽  
Nabh4 Reduction

In the work, we firstly report the facile and large-scale synthesis of defective black TiO2−x(B) nanosheets via a dual-zone NaBH4 reduction method. The structure, physico-chemical, and optical properties of TiO2−x(B) nanosheets were systematically characterized by powder X-ray diffraction, Raman spectroscopy, UV-Vis absorption spectroscopy, and X-ray photoelectron spectroscopy, etc. The concentration of Ti3+ can be well tuned by NaBH4 reduction. With increasing the mass ratio of NaBH4 to TiO2(B), the generation of Ti3+ defects gives rise to the increased intensity of a broad band absorption in the visible wavelength range. It is demonstrated that the TiO2−x(B) photocatalyst synthesized with the mass ratio of NaBH4 to TiO2(B) of 3:1 exhibited an optimum photocatalytic activity and excellent photostability for hydrogen evolution under visible-light irradiation. By combining the advantages of 2D TiO2(B) nanosheets architecture with those of Ti3+ self-doping and simultaneous production of oxygen vacancy sites, the enhanced photocatalytic performance of the defective TiO2−x(B) nanosheets was achieved.

scholarly journals MoSe2-GO/rGO Composite Catalyst for Hydrogen Evolution Reaction

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1309 ◽  
Author(s):  
Wenwu Guo ◽  
Quyet Le ◽  
Amirhossein Hasani ◽  
Tae Lee ◽  
Ho Jang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Photoelectron Spectroscopy ◽  
Transition Metal Dichalcogenides ◽  
Catalytic Performance ◽  
Composite Catalyst ◽  
X Ray ◽  
Molybdenum Selenide

There has been considerable research to engineer composites of transition metal dichalcogenides with other materials to improve their catalytic performance. In this work, we present a modified solution-processed method for the formation of molybdenum selenide (MoSe2) nanosheets and a facile method of structuring composites with graphene oxide (GO) or reduced graphene oxide (rGO) at different ratios to prevent aggregation of the MoSe2 nanosheets and hence improve their electrocatalytic hydrogen evolution reaction performance. The prepared GO, rGO, and MoSe2 nanosheets were characterized by X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. The electrocatalytic performance results showed that the pure MoSe2 nanosheets exhibited a somewhat high Tafel slope of 80 mV/dec, whereas the MoSe2-GO and MoSe2-rGO composites showed lower Tafel slopes of 57 and 67 mV/dec at ratios of 6:4 and 4:6, respectively. We attribute the improved catalytic effects to the better contact and faster carrier transfer between the edge of MoSe2 and the electrode due to the addition of GO or rGO.

scholarly journals Development of a nitrogen-doped 2D material for tribological applications in the boundary-lubrication regime

2017 ◽  
Vol 8 ◽  
pp. 1476-1483 ◽  
Author(s):  
Shende Rashmi Chandrabhan ◽  
Velayudhanpillai Jayan ◽  
Somendra Singh Parihar ◽  
Sundara Ramaprabhu
Keyword(s):  
Electron Microscopy ◽  
Tribological Properties ◽  
Photoelectron Spectroscopy ◽  
Large Scale ◽  
Synthesis Method ◽  
Field Trials ◽  
Base Oil ◽  
X Ray ◽  
Nitrogen Doped ◽  
Sliding Mechanism

The present paper describes a facile synthesis method for nitrogen-doped reduced graphene oxide (N-rGO) and the application of N-rGO as an effective additive for improving the tribological properties of base oil. N-rGO has been characterized by different characterization techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. N-rGO-based nanolubricants are prepared and their tribological properties are studied using a four-ball tester. The nanolubricants show excellent stability over a period of six months and a significant decrease in coefficient of friction (25%) for small amounts of N-rGO (3 mg/L). The improvement in tribological properties can be attributed to the sliding mechanism of N-rGO accompanied by the high mechanical strength of graphene. Further, the nanolubricant is prepared at large scale (700 liter) and field trials are carried out at one NTPC thermal plant in India. The implementation of the nanolubricant in an induced draft (ID) fan results in the remarkable decrease in the power consumption.

scholarly journals Electrochemical Hydrogen Evolution over Hydrothermally Synthesized Re-Doped MoS2 Flower-Like Microspheres

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4631 ◽  
Author(s):  
Juan Aliaga ◽  
Pablo Vera ◽  
Juan Araya ◽  
Luis Ballesteros ◽  
Julio Urzúa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Photoelectron Spectroscopy ◽  
Charge Transfer Resistance ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Transfer Resistance ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

In this research, we report a simple hydrothermal synthesis to prepare rhenium (Re)- doped MoS2 flower-like microspheres and the tuning of their structural, electronic, and electrocatalytic properties by modulating the insertion of Re. The obtained compounds were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Structural, morphological, and chemical analyses confirmed the synthesis of poorly crystalline Re-doped MoS2 flower-like microspheres composed of few stacked layers. They exhibit enhanced hydrogen evolution reaction (HER) performance with low overpotential of 210 mV at current density of 10 mA/cm2, with a small Tafel slope of 78 mV/dec. The enhanced catalytic HER performance can be ascribed to activation of MoS2 basal planes and by reduction in charge transfer resistance during HER upon doping.

scholarly journals Nitrogen-Doped Porous Carbon Derived from Biomass Used as Trifunctional Electrocatalyst toward Oxygen Reduction, Oxygen Evolution and Hydrogen Evolution Reactions

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 76 ◽  
Author(s):  
Chinnusamy Sathiskumar ◽  
Shanmugam Ramakrishnan ◽  
Mohanraj Vinothkannan ◽  
Ae Rhan Kim ◽  
Srinivasan Karthikeyan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Oxygen Reduction ◽  
Hydrogen Evolution ◽  
Oxygen Evolution ◽  
Porous Carbon ◽  
Photoelectron Spectroscopy ◽  
Energy Storage And Conversion ◽  
X Ray ◽  
Metal Free ◽  
Hydrogen Evolution Reactions

Tremendous developments in energy storage and conversion technologies urges researchers to develop inexpensive, greatly efficient, durable and metal-free electrocatalysts for tri-functional electrochemical reactions, namely oxygen reduction reactions (ORRs), oxygen evolution reactions (OERs) and hydrogen evolution reactions (HERs). In these regards, this present study focuses upon the synthesis of porous carbon (PC) or N-doped porous carbon (N-PC) acquired from golden shower pods biomass (GSB) via solvent-free synthesis. Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) studies confirmed the doping of nitrogen in N-PC. In addition, morphological analysis via field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) provide evidence of the sheet-like porous structure of N-PC. ORR results from N-PC show the four-electron pathway (average n = 3.6) for ORRs with a Tafel slope of 86 mV dec−1 and a half-wave potential of 0.76 V. For OERs and HERs, N-PC@Ni shows better overpotential values of 314 and 179 mV at 10 mA cm−2, and its corresponding Tafel slopes are 132 and 98 mV dec−1, respectively. The chronopotentiometry curve of N-PC@Ni reveals better stability toward OER and HER at 50 mA cm−2 for 8 h. These consequences provide new pathways to fabricate efficient electrocatalysts of metal-free heteroatom-doped porous carbon from bio-waste/biomass for energy application in water splitting and metal air batteries.

Large Scale Preparation of β-AgVO3 Nanowires Using a Novel Sonochemical Route

2008 ◽  
Vol 8 (6) ◽  
pp. 3203-3207 ◽  
Author(s):  
Changjie Mao ◽  
Xingcai Wu ◽  
Jun-Jie Zhu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Lithium Ion Batteries ◽  
Photoelectron Spectroscopy ◽  
Large Scale ◽  
Lithium Ion ◽  
Gravimetric Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

A large number of β-AgVO3 nanowires with diameter of 30–60 nm, and length of 1.5–3 μm have been successfully synthesized by a simple and facile low-temperature sonochemical route. The morphologies and structures of the nanowires were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning transmission electron microscopy (SEM), and thermal gravimetric analysis (TGA). Cyclic voltammetry and charge–discharge experiments were applied to characterize the electrochemical properties of the nanowires as cathode materials for lithium-ion batteries. In the initial discharge and charge process, the as-prepared β-AgVO3 nanowires showed the initial charge and discharge capacities of 69 and 102 (mAh)/g, respectively. It is anticipated that the β-AgVO3 nanostructures are promising cathode candidates in the application of primary lithium-ion batteries.

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