scholarly journals Highly active catalyst derived from a 3D foam of Fe(PO3)2/Ni2P for extremely efficient water oxidation

2017 ◽  
Vol 114 (22) ◽  
pp. 5607-5611 ◽  
Author(s):  
Haiqing Zhou ◽  
Fang Yu ◽  
Jingying Sun ◽  
Ran He ◽  
Shuo Chen ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Large Scale ◽  
Nickel Foam ◽  
Alkaline Electrolyte ◽  
Nickel Iron ◽  
Noble Metal Catalysts ◽  
Long Term Stability ◽  
Highly Active ◽  
High Durability ◽  
Oxygen Evolving

Commercial hydrogen production by electrocatalytic water splitting will benefit from the realization of more efficient and less expensive catalysts compared with noble metal catalysts, especially for the oxygen evolution reaction, which requires a current density of 500 mA/cm2 at an overpotential below 300 mV with long-term stability. Here we report a robust oxygen-evolving electrocatalyst consisting of ferrous metaphosphate on self-supported conductive nickel foam that is commercially available in large scale. We find that this catalyst, which may be associated with the in situ generated nickel–iron oxide/hydroxide and iron oxyhydroxide catalysts at the surface, yields current densities of 10 mA/cm2 at an overpotential of 177 mV, 500 mA/cm2 at only 265 mV, and 1,705 mA/cm2 at 300 mV, with high durability in alkaline electrolyte of 1 M KOH even after 10,000 cycles, representing activity enhancement by a factor of 49 in boosting water oxidation at 300 mV relative to the state-of-the-art IrO2 catalyst.

scholarly journals WS(1−x)Sex Nanoparticles Decorated Three-Dimensional Graphene on Nickel Foam: A Robust and Highly Efficient Electrocatalyst for the Hydrogen Evolution Reaction

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 929 ◽  
Author(s):  
Sajjad Hussain ◽  
Kamran Akbar ◽  
Dhanasekaran Vikraman ◽  
Rana Afzal ◽  
Wooseok Song ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Large Scale ◽  
Nickel Foam ◽  
Transition Metal Dichalcogenides ◽  
Three Dimensional ◽  
Cost Effective ◽  
Highly Efficient ◽  
Highly Active ◽  
Earth Abundant

To find an effective alternative to scarce, high-cost noble platinum (Pt) electrocatalyst for hydrogen evolution reaction (HER), researchers are pursuing inexpensive and highly efficient materials as an electrocatalyst for large scale practical application. Layered transition metal dichalcogenides (TMDCs) are promising candidates for durable HER catalysts due to their cost-effective, highly active edges and Earth-abundant elements to replace Pt electrocatalysts. Herein, we design an active, stable earth-abundant TMDCs based catalyst, WS(1−x)Sex nanoparticles-decorated onto a 3D porous graphene/Ni foam. The WS(1−x)Sex/graphene/NF catalyst exhibits fast hydrogen evolution kinetics with a moderate overpotential of ~−93 mV to drive a current density of 10 mA cm−2, a small Tafel slope of ~51 mV dec−1, and a long cycling lifespan more than 20 h in 0.5 M sulfuric acid, which is much better than WS2/NF and WS2/graphene/NF catalysts. Our outcomes enabled a way to utilize the TMDCs decorated graphene and precious-metal-free electrocatalyst as mechanically robust and electrically conductive catalyst materials.

scholarly journals Highly active oxygen evolution integrated with efficient CO2 to CO electroreduction

2019 ◽  
Vol 116 (48) ◽  
pp. 23915-23922 ◽  
Author(s):  
Yongtao Meng ◽  
Xiao Zhang ◽  
Wei-Hsuan Hung ◽  
Junkai He ◽  
Yi-Sheng Tsai ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Water Oxidation ◽  
Iron Hydroxide ◽  
Fuel Efficiency ◽  
Cell Voltage ◽  
Electrical Energy ◽  
Reduction Reaction ◽  
Faradaic Efficiency ◽  
Nickel Iron ◽  
Highly Active

Electrochemical reduction of CO2 to useful chemicals has been actively pursued for closing the carbon cycle and preventing further deterioration of the environment/climate. Since CO2 reduction reaction (CO2RR) at a cathode is always paired with the oxygen evolution reaction (OER) at an anode, the overall efficiency of electrical energy to chemical fuel conversion must consider the large energy barrier and sluggish kinetics of OER, especially in widely used electrolytes, such as the pH-neutral CO2-saturated 0.5 M KHCO3. OER in such electrolytes mostly relies on noble metal (Ir- and Ru-based) electrocatalysts in the anode. Here, we discover that by anodizing a metallic Ni–Fe composite foam under a harsh condition (in a low-concentration 0.1 M KHCO3 solution at 85 °C under a high-current ∼250 mA/cm2), OER on the NiFe foam is accompanied by anodic etching, and the surface layer evolves into a nickel–iron hydroxide carbonate (NiFe-HC) material composed of porous, poorly crystalline flakes of flower-like NiFe layer-double hydroxide (LDH) intercalated with carbonate anions. The resulting NiFe-HC electrode in CO2-saturated 0.5 M KHCO3 exhibited OER activity superior to IrO2, with an overpotential of 450 and 590 mV to reach 10 and 250 mA/cm2, respectively, and high stability for >120 h without decay. We paired NiFe-HC with a CO2RR catalyst of cobalt phthalocyanine/carbon nanotube (CoPc/CNT) in a CO2 electrolyzer, achieving selective cathodic conversion of CO2 to CO with >97% Faradaic efficiency and simultaneous anodic water oxidation to O2. The device showed a low cell voltage of 2.13 V and high electricity-to-chemical fuel efficiency of 59% at a current density of 10 mA/cm2.

scholarly journals Cobalt–metalloid alloys for electrochemical oxidation of 5-hydroxymethylfurfural as an alternative anode reaction in lieu of oxygen evolution during water splitting

2018 ◽  
Vol 14 ◽  
pp. 1436-1445 ◽  
Author(s):  
Jonas Weidner ◽  
Stefan Barwe ◽  
Kirill Sliozberg ◽  
Stefan Piontek ◽  
Justus Masa ◽  
...  
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Large Scale ◽  
Nickel Foam ◽  
Waste Product ◽  
Suitable Alternative ◽  
Faradaic Efficiency ◽  
Valuable Product

The electrochemical water splitting commonly involves the cathodic hydrogen and anodic oxygen evolution reactions (OER). The oxygen evolution reaction is more energetically demanding and kinetically sluggish and represents the bottleneck for a commercial competitiveness of electrochemical hydrogen production from water. Moreover, oxygen is essentially a waste product of low commercial value since the primary interest is to convert electrical energy into hydrogen as a storable energy carrier. We report on the anodic oxidation of 5-hydroxymethylfurfural (HMF) to afford the more valuable product 2,5-furandicarboxylic acid (FDCA) as a suitable alternative to the oxygen evolution reaction. Notably, HMF oxidation is thermodynamically more favorable than water oxidation and hence leads to an overall improved energy efficiency for H2 production. In addition, contrary to the “waste product O2”, FDCA can be further utilized, e.g., for production of polyethylene 2,5-furandicarboxylate (PEF), a sustainable polymer analog to polyethylene terephthalate (PET) and thus represents a valuable product for the chemical industry with potential large scale use. Various cobalt–metalloid alloys (CoX; X = B, Si, P, Te, As) were investigated as potential catalysts for HMF oxidation. In this series, CoB required 180 mV less overpotential to reach a current density of 55 mA cm−2 relative to OER with the same electrode. Electrolysis of HMF using a CoB modified nickel foam electrode at 1.45 V vs RHE achieved close to 100% selective conversion of HMF to FDCA at 100% faradaic efficiency.

scholarly journals Nickel-Iron Layered Double Hydroxide for Highly Efficient Oxygen Evolution Reaction

2021 ◽  
Vol 290 ◽  
pp. 01036
Author(s):  
Qiuyu Zhao ◽  
Wenke Xi ◽  
Jianjun Wang
Keyword(s):  
Oxygen Evolution ◽  
Layered Double Hydroxide ◽  
Oxygen Evolution Reaction ◽  
Nickel Foam ◽  
Chemical Route ◽  
Nickel Iron ◽  
Long Term Stability ◽  
3D Space ◽  
New Strategy ◽  
Double Hydroxide

It is extensively accepted that electrolysis of water producing regenerable energy is a crucial substitution of traditional fuel strategy. Herein, we report a wet-chemical route to Ni-Fe layered double hydroxide (LDH) interconnected nanosheets with large surface area with the support of vertically aligned ZnO microrods arrays on the nickel foam (Ni-Fe LDH@ZnO/NF) for oxygen evolution reaction. Owing to the 2D Ni-Fe LDH nanosheets distributed in 3D space, the Ni-Fe LDH@ZnO/NF demonstrates excellent OER performances with a reasonably low overpotential of 271 mV at a current density of 10 mA·cm-2, and a long-term stability up to 29 hours. This work proposes a new strategy to prepare Ni-Fe LDH/NF as efficient OER catalyst.

scholarly journals Towards stable and highly active IrO2 catalysts supported on doped tin oxides for the oxygen evolution reaction in acidic media

2022 ◽  
Vol 334 ◽  
pp. 03001
Author(s):  
Sofia Delgado ◽  
Paranjeet Lakhtaria ◽  
Eva Sousa ◽  
Tiago Lagarteira ◽  
K.A. Friedrich ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Large Scale ◽  
Proton Exchange Membrane ◽  
Active Surface ◽  
Proton Exchange ◽  
Polyol Synthesis ◽  
Surface Areas ◽  
Highly Active ◽  
Tin Oxides ◽  
Metal Doped

Iridium oxide is the preferred catalyst for water oxidation but it is required to maximize its utilization to deploy Proton Exchange Membrane Water Electrolyzers (PEMWEs) into the large-scale applications panorama. A promising pathway for dispersing this precious catalyst is on an electric conductive and stable support. However, there is a lack of understanding how the support-catalyst interactions affect the stability/activity of the electrocatalyst under anodic conditions. This work discloses a modified, easy-scalable, polyol synthesis protocol to produce a highly active and stable iridium-based catalyst, supported on metal-doped tin oxides. The loading of Ir was reduced 30 wt.% compared to the reference IrO2, and dispersed on Sb-SnO2 (IrOx/ATO), In-SnO2 (IrOx/ITO) and SnO2 supports. All synthesized electrocatalysts not only surpassed the OER-mass activity of a commercial catalyst (IrO2) – reference – but also reached higher electrochemical active surface areas and enhanced stability under the OER conditions. The highest performance was achieved with Ir NPs supported on ITO (176 A/gIr vs. 15.5 A/gIr for the reference catalyst @ 1.51 V vs. RHE) and both IrOx/ITO and IrOx/SnO2 catalysts demonstrated remarkable stability after cycling the electrode and performing long-term chronopotentiometry. ITO is, therefore, an auspicious support to serve Ir-based catalysts as it favors a good bargain between activity and stability, while drastically reducing the amount of noble metal.

Large-scale QM/MM calculations of the CaMn4O5 cluster in the S3 state of the oxygen evolving complex of photosystem II. Comparison between water-inserted and no water-inserted structures

2017 ◽  
Vol 198 ◽  
pp. 83-106 ◽  
Author(s):  
Mitsuo Shoji ◽  
Hiroshi Isobe ◽  
Takahito Nakajima ◽  
Yasuteru Shigeta ◽  
Michihiro Suga ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Water Oxidation ◽  
Large Scale ◽  
Geometrical Structure ◽  
Bond Formation ◽  
Oxygen Evolving Complex ◽  
Computational Results ◽  
Hydroxide Anion ◽  
The Right ◽  
Oxygen Evolving

Large-scale QM/MM calculations were performed to elucidate an optimized geometrical structure of a CaMn4O5 cluster with and without water insertion in the S3 state of the oxygen evolving complex (OEC) of photosystem II (PSII). The left (L)-opened structure was found to be stable under the assumption of no hydroxide anion insertion in the S3 state, whereas the right (R)-opened structure became more stable if one water molecule is inserted to the Mn4Ca cluster. The optimized Mna(4)–Mnd(1) distance determined by QM/MM was about 5.0 Å for the S3 structure without an inserted hydroxide anion, but this is elongated by 0.2–0.3 Å after insertion. These computational results are discussed in relation to the possible mechanisms of O–O bond formation in water oxidation by the OEC of PSII.

FeMoO4nanorod array: a highly active 3D anode for water oxidation under alkaline conditions

2018 ◽  
Vol 5 (3) ◽  
pp. 665-668 ◽  
Author(s):  
Ying Gou ◽  
Qin Liu ◽  
Zhiang Liu ◽  
Abdullah M. Asiri ◽  
Xuping Sun ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Current Density ◽  
Water Oxidation ◽  
Nickel Foam ◽  
Nanorod Array ◽  
Catalytic Current ◽  
Highly Active ◽  
Alkaline Conditions

As a durable water oxidation electrocatalyst, an FeMoO4nanorod array on nickel foam (FeMoO4/NF) shows superior catalytic activity offering a geometrical catalytic current density of 50 mA cm−2at an overpotential of only 293 mV in 1.0 M KOH.

A nickel-borate nanoarray: a highly active 3D oxygen-evolving catalyst electrode operating in near-neutral water

2017 ◽  
Vol 53 (21) ◽  
pp. 3070-3073 ◽  
Author(s):  
Xuqiang Ji ◽  
Liang Cui ◽  
Danni Liu ◽  
Shuai Hao ◽  
Jingquan Liu ◽  
...  
Keyword(s):  
High Activity ◽  
Current Density ◽  
Water Oxidation ◽  
Carbon Cloth ◽  
Highly Active ◽  
Neutral Water ◽  
Oxygen Evolving ◽  
Electrolyte Ph ◽  
A Current ◽  
Catalyst Electrode

A nickel-borate nanoarray on carbon cloth (Ni-Bi/CC) derived from NiO/CC shows high activity and durability for water oxidation electrocatalysis in a borate electrolyte (pH 9.2), offering a current density of 10 mA cm−2 at an overpotential of 470 mV.

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