scholarly journals The rise of hematite: origin and strategies to reduce the high onset potential for the oxygen evolution reaction

2015 ◽  
Vol 3 (33) ◽  
pp. 16896-16912 ◽  
Author(s):  
Beniamino Iandolo ◽  
Björn Wickman ◽  
Igor Zorić ◽  
Anders Hellman
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Large Scale ◽  
Electrochemical Potential ◽  
Onset Potential

The prospect of large scale light-driven water splitting on hematite (Fe2O3) is currently hampered by the high electrochemical potential required to initiate the water oxidation.

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 Single-atom cobalt-hydroxyl modification of polymeric carbon nitride for highly enhanced photocatalytic water oxidation: ball milling increased single atom loading

2022 ◽  
Author(s):  
Fei Yu ◽  
Tingting Huo ◽  
Quanhua Deng ◽  
Guoan Wang ◽  
Yuguo Xia ◽  
...  
Keyword(s):  
Ball Milling ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Carbon Nitride ◽  
Single Atom ◽  
Overall Water Splitting ◽  
Polymeric Carbon

Expediting the oxygen evolution reaction (OER) is the key to achieving efficient photocatalytic overall water splitting. Herein, single-atom Co−OH modified polymeric carbon nitride (Co-PCN) was synthesized with single-atom loading increased...

Fe-Co-P multi-heterostructure arrays for efficient electrocatalytic water splitting

2021 ◽  
Author(s):  
Hanwen Xu ◽  
Jiawei Zhu ◽  
Pengyan Wang ◽  
Ding Chen ◽  
Chengtian Zhang ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Hydrogen Evolution ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Oxygen Evolution Reaction ◽  
Rational Design ◽  
Large Scale ◽  
High Efficiency ◽  
Bifunctional Catalysts

Rational design and construction of high-efficiency bifunctional catalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is crucial for large-scale hydrogen production by water splitting. Herein, by a...

Zinc-telluride nanospheres as an efficient water oxidation electrocatalyst displaying a low overpotential for oxygen evolution

2019 ◽  
Vol 7 (46) ◽  
pp. 26410-26420 ◽  
Author(s):  
Maira Sadaqat ◽  
Laraib Nisar ◽  
Noor-Ul-Ain Babar ◽  
Fayyaz Hussain ◽  
Muhammad Naeem Ashiq ◽  
...  
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Zinc Telluride ◽  
Low Overpotential ◽  
Electrochemical Water Splitting ◽  
Kinetics Of

Electrochemical water splitting is economically unviable due to the sluggish kinetics of the anodically uphill oxygen evolution reaction (OER).

Triple hierarchy and double synergies of NiFe/Co9S8/carbon cloth: a new and efficient electrocatalyst for the oxygen evolution reaction

Nanoscale ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 3378-3385 ◽  
Author(s):  
Changhong Zhan ◽  
Zheng Liu ◽  
Yang Zhou ◽  
Mingliang Guo ◽  
Xiaolin Zhang ◽  
...  
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Oxidation Catalyst ◽  
Carbon Cloth ◽  
Electrochemical Water Splitting

Electrochemical water splitting requires an efficient water oxidation catalyst to accelerate the oxygen evolution reaction (OER).

Facile construction of self-supported Fe-doped Ni3S2 nanoparticle arrays for ultralow-overpotential oxygen evolution reaction

Nanoscale ◽  
2020 ◽  
Author(s):  
Ning Xie ◽  
Dong-Dong Ma ◽  
Xintao Wu ◽  
Qi-Long Zhu
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
High Performance ◽  
Cost Effective ◽  
Nanoparticle Arrays ◽  
Overall Water Splitting ◽  
Construction Of Self ◽  
One Step

Constructing high-performance and cost-effective electrocatalysts for water oxidation, particularly for overall water splitting is extremely needed, whereas still challenging. Herein, based on an economical and facile one-step surface sulfurization strategy,...

scholarly journals Surface Modification of Hematite Photoanodes for Improvement of Photoelectrochemical Performance

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 497 ◽  
Author(s):  
Lifei Xi ◽  
Kathrin Lange
Keyword(s):  
Surface Modification ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Water Oxidation ◽  
Oxidation Kinetics ◽  
Surface Passivation ◽  
Earth Metal ◽  
Photoelectrochemical Performance ◽  
Onset Potential ◽  
Solar Water Splitting

Solar water splitting is a promising method for producing renewable fuels. Thermodynamically, the overall water splitting reaction is an uphill reaction involving a multiple electron transfer process. The oxygen evolution reaction (OER) has been identified as the bottleneck process. Hematite (α-Fe2O3) is one of the best photoanode material candidates due to its band gap properties and stability in aqueous solution. However, the reported efficiencies of hematite are notoriously lower than the theoretically predicted value mainly due to poor charge transfer and separation ability, short hole diffusion length as well as slow water oxidation kinetics. In this Review Article, several emerging surface modification strategies to reduce the oxygen evolution overpotential and thus to enhance the water oxidation reaction kinetics will be presented. These strategies include co-catalysts loading, photoabsorption enhancing (surface plasmonic metal and rare earth metal decoration), surface passivation layer deposition, surface chemical etching and surface doping. These methods are found to reduce charge recombination happening at surface trapping states, promote charge separation and diffusion, and accelerate water oxidation kinetics. The detailed surface modification methods, surface layer materials, the photoelectrochemical (PEC) performances including photocurrent and onset potential shift as well as the related proposed mechanisms will be reviewed.

Mesoporous Ni–Fe oxide multi-composite hollow nanocages for efficient electrocatalytic water oxidation reactions

2017 ◽  
Vol 5 (9) ◽  
pp. 4320-4324 ◽  
Author(s):  
Bong Kyun Kang ◽  
Moo Hyun Woo ◽  
Jooyoung Lee ◽  
Young Hyun Song ◽  
Zhongli Wang ◽  
...  
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Anode Material ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Cycling Stability ◽  
Great Promise ◽  
Oxidation Reactions ◽  
Fe Oxide ◽  
Excellent Cycling Stability

The mesoporous NiO/NiFe2O4multi-composite hollow nanocage electrodes are fabricated and achieve a low overpotential (303 mV at 10 mV cm−2) and Tafel plot (58.5 mV dec−1), respectively, and excellent cycling stability (12 h) as an anode material for oxygen evolution reaction, holding great promise for water splitting.

scholarly journals Cooperative Catalytic Behavior of SnO2 and NiWO4 over BiVO4 Photoanodes for Enhanced Photoelectrochemical Water Splitting Performance

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 879 ◽  
Author(s):  
Maged N. Shaddad ◽  
Prabhakarn Arunachalam ◽  
Mahmoud Hezam ◽  
Abdullah M. Al-Mayouf
Keyword(s):  
Buffer Layer ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Synergetic Effect ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Solar Simulator

n-BiVO4 is a favorable photoelectrode candidate for a photoelectrochemical (PEC) water splitting reaction owing to its suitable energy level edge locations for an oxygen evolution reaction. On the other hand, the sluggish water oxidation kinetics of BiVO4 photoanodes when used individually make it necessary to use a hole blocking layer as well as water oxidation catalysts to overcome the high kinetic barrier for the PEC water oxidation reaction. Here, we describe a very simple synthetic strategy to fabricate nanocomposite photoanodes that synergistically address both of these critical limitations. In particular, we examine the effect of a SnO2 buffer layer over BiVO4 films and further modify the photoanode surface with a crystalline nickel tungstate (NiWO4) nanoparticle film to boost PEC water oxidation. When NiWO4 is incorporated over BiVO4/SnO2 films, the PEC performance of the resultant triple-layer NiWO4/BiVO4/SnO2 films for the oxygen evolution reaction (OER) is further improved. The enhanced performance for the PEC OER is credited to the synergetic effect of the individual layers and the introduction of a SnO2 buffer layer over the BiVO4 film. The optimized NiWO4/BiVO4/SnO2 electrode demonstrated both enriched visible light absorption and achieves charge separation and transfer efficiencies of 23% and 30%, respectively. The photoanodic current density for the OER on optimized NiWO4/BiVO4/SnO2 photoanode shows a maximum photocurrent of 0.93 mA/cm2 at 1.23 V vs. RHE in a phosphate buffer solution (pH~7.5) under an AM1.5G solar simulator, which is an incredible five-fold and two-fold enhancement compared to its parent BiVO4 photoanode and BiVO4/SnO2 photoanodes, respectively. Further, the incorporation of the NiWO4 co-catalyst over the BiVO4/SnO2 film increases the interfacial electron transfer rate across the composite/solution interface.

Co–Fe Bimetal Phosphate Composite Loaded on Reduced Graphene Oxide for Oxygen Evolution

NANO ◽  
2019 ◽  
Vol 14 (01) ◽  
pp. 1950003 ◽  
Author(s):  
Guoxing Zhu ◽  
Xulan Xie ◽  
Lisong Xiao ◽  
Xiaoyun Li ◽  
Xiaoping Shen ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
High Performance ◽  
Synergistic Effects ◽  
Water Electrolysis ◽  
Onset Potential ◽  
Reduced Graphene

Development of high-performance nonprecious metal-based catalysts for oxygen evolution reaction (OER) is crucial to improve the efficiency of water electrolysis and photoelectrochemical water splitting for harvesting and storage of solar energy. Herein, Co–Fe phosphates and their composites with reduced graphene oxide (rGO) were prepared by a simple hydrothermal method, which then acted as oxygen evolution reaction catalysts. In 1.0 M KOH aqueous solution, the as-obtained optimal composite, Co–Fe phosphate/rGO, can catalyze oxygen evolution reaction with a very sharp onset potential and a small over-potential of 338[Formula: see text]mV to achieve a current density of 10[Formula: see text]mA[Formula: see text]cm[Formula: see text]. It was found that in these Co–Fe phosphates, the optimal Co:Fe ratio is 0.75:0.25. The excellent electrocatalytic performance of the Co–Fe phosphate/rGO composite would benefit from the synergistic effects between Fe and Co species, as well as rGO substrate providing conductive channels. The formed Co–Fe phosphate/rGO electrocatalysts can be the promising replacement of precious metal-based catalysts for more practical and cost-efficient water splitting.

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