scholarly journals Extraction of non-noble metal columbite-tantalite as a highly efficient electrocatalyst for water splitting

2021 ◽  
Author(s):  
Patrick Bacirhonde ◽  
Nelson Dzade ◽  
Carmen Chalony ◽  
Jeesoo Park ◽  
Emmanuel Afranie ◽  
...  
Keyword(s):  
Water Splitting ◽  
Density Functional ◽  
Large Scale ◽  
Hydrogen Adsorption ◽  
Alkaline Media ◽  
Great Promise ◽  
Scale Production ◽  
Overall Water Splitting ◽  
Production Of Hydrogen ◽  
Low Overpotential

Abstract Abstract The development of robust and inexpensive electrocatalysts that are capable of catalyzing the overall water splitting reaction is highly essential for large scale production of hydrogen. Herein, we report the successful liquid-liquid extraction and hydrothermal synthesis of a highly stable columbite-tantalite electrocatalysts (Fe0.79Mn0.21Nb0.16Ta0.84O6) with remarkable HER and OER performance in alkaline media. The extracted Fe0.79Mn0.21Nb0.16Ta0.84O6 electrocatalyst shows a low overpotential of 190.2 and 284.8 mV at 10/mA cm-2 in current density in situ for HER and OER, respectively. The electrocatalyst also exhibited low Tafel slopes of 56.36 mV/dec for HER and 112.85 mV/dec for OER, verifying their rapid catalytic kinetics. The electrolyzer maintained the cell voltage of 1.63 V and potential-time stability close to that of Pt/C & RuO2/C. The intrinsic mechanism for the exceptional HER and OER performance was further unravelled through first-principles density functional theory (DFT) calculations, predicting very low Gibbs free energy of hydrogen adsorption (ΔGH* ≈ 0.09 eV) and low overpotential (η = 0.47 eV at the Mn sites) for OER on the Fe0.75Mn0.25Ta1.875Nb0.125O6 catalyst. Our results demonstrate that columbite-tantalite electrocatalysts offer great promise for efficient overall water splitting. Graphical abstract

scholarly journals Stabilized Hydroxide-Mediated Nickel-Based Electrocatalysts for High-Current-Density Hydrogen Evolution in Alkaline Media

2021 ◽  
Author(s):  
Yuting Luo ◽  
Zhiyuan Zhang ◽  
Fengning Yang ◽  
Jiong Li ◽  
Zhibo Liu ◽  
...  
Keyword(s):  
Water Splitting ◽  
Large Scale ◽  
Fossil Fuels ◽  
High Current Density ◽  
Critical Energy ◽  
Alkaline Media ◽  
Scale Production ◽  
High Current ◽  
Large Scale Production ◽  
Electrochemical Water Splitting

Large-scale production of green hydrogen by electrochemical water splitting is considered as a promising technology to address critical energy challenges caused by the extensive use of fossil fuels. Although nonprecious...

Iron and Nitrogen Co-doped CoSe2 Nanosheet Arrays for Robust Electrocatalytic Water Oxidation

2021 ◽  
Author(s):  
Di Li ◽  
Yingying Xing ◽  
Changjian Zhou ◽  
Yikai Lu ◽  
Shengjie Xu ◽  
...  
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Energy Barrier ◽  
Large Scale ◽  
Scale Production ◽  
Reaction Energy ◽  
Large Scale Production ◽  
Nanosheet Arrays ◽  
Production Of Hydrogen ◽  
Co Doped

The high reaction energy barrier of the oxygen evolution reaction (OER) extremely reduces the efficiency of water splitting, which is not conducive to large-scale production of hydrogen. Due to the...

scholarly journals Electrochemically derived functionalized graphene for bulk production of hydrogen peroxide

2020 ◽  
Vol 11 ◽  
pp. 432-442 ◽  
Author(s):  
Munaiah Yeddala ◽  
Pallavi Thakur ◽  
Anugraha A ◽  
Tharangattu N Narayanan
Keyword(s):  
Large Scale ◽  
Reduction Reaction ◽  
Single Step ◽  
Scale Production ◽  
Functionalized Graphene ◽  
Large Scale Production ◽  
Production Of Hydrogen ◽  
Electron Reduction ◽  
Bulk Production ◽  
Carbon Based

On-site peroxide generation via electrochemical reduction is gaining tremendous attention due to its importance in many fields, including water treatment technologies. Oxidized graphitic carbon-based materials have been recently proposed as an alternative to metal-based catalysts in the electrochemical oxygen reduction reaction (ORR), and in this work we unravel the role of C=O groups in graphene towards sustainable peroxide formation. We demonstrate a versatile single-step electrochemical exfoliation of graphite to graphene with a controllable degree of oxygen functionalities and thickness, leading to the formation of large quantities of functionalized graphene with tunable rate parameters, such as the rate constant and exchange current density. Higher oxygen-containing exfoliated graphene is known to undergo a two-electron reduction path in ORR having an efficiency of about 80 ± 2% even at high overpotential. Bulk production of H2O2 via electrolysis was also demonstrated at low potential (0.358 mV vs RHE), yielding ≈34 mg/L peroxide with highly functionalized (≈23 atom %) graphene and ≈16 g/L with low functionalized (≈13 atom %) graphene, which is on par with the peroxide production using state-of-the-art precious-metal-based catalysts. Hence this method opens a new scheme for the single-step large-scale production of functionalized carbon-based catalysts (yield ≈45% by weight) that have varying functionalities and can deliver peroxide via the electrochemical ORR process.

scholarly journals Bilayer MoSe2/HfS2 Nanocomposite as a Potential Visible-Light-Driven Z-Scheme Photocatalyst

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1706 ◽  
Author(s):  
Biao Wang ◽  
Xiaotian Wang ◽  
Peng Wang ◽  
Tie Yang ◽  
Hongkuan Yuan ◽  
...  
Keyword(s):  
Visible Light ◽  
Water Splitting ◽  
Density Functional ◽  
Infrared Region ◽  
Internal Electric Field ◽  
Functional Theory ◽  
Overall Water Splitting ◽  
Visible Light Driven ◽  
Electron Migration ◽  
Redox Ability

Visible-light-driven photocatalytic overall water splitting is deemed to be an ideal way to generate clean and renewable energy. The direct Z-scheme photocatalytic systems, which can realize the effective separation of photoinduced carriers and possess outstanding redox ability, have attracted a huge amount of interest. In this work, we have studied the photocatalytic performance of the bilayer MoSe2/HfS2 van der Waals (vdW) heterojunction following the direct Z-scheme mechanism by employing the hybrid density functional theory. Our calculated results show that the HfS2 and MoSe2 single layers in this heterojunction are used for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. The charge transfer between the two layers brought about an internal electric field pointing from the MoSe2 layer to the HfS2 slab, which can accelerate the separation of the photoinduced electron–hole pairs and support the Z-scheme electron migration near the interface. Excitingly, the optical absorption intensity of the MoSe2/HfS2 heterojunction is enhanced in the visible and infrared region. As a result, these results reveal that the MoSe2/HfS2 heterojunction is a promising direct Z-scheme photocatalyst for photocatalytic overall water splitting.

scholarly journals Nickel foam and stainless steel mesh as electrocatalysts for hydrogen evolution reaction, oxygen evolution reaction and overall water splitting in alkaline media

RSC Advances ◽  
2019 ◽  
Vol 9 (54) ◽  
pp. 31563-31571 ◽  
Author(s):  
Xiaoyan Hu ◽  
Xuemei Tian ◽  
Ying-Wu Lin ◽  
Zhonghua Wang
Keyword(s):  
Stainless Steel ◽  
Water Splitting ◽  
Hydrogen Evolution Reaction ◽  
Oxygen Evolution Reaction ◽  
Nickel Foam ◽  
Low Cost ◽  
Alkaline Media ◽  
Stainless Steel Mesh ◽  
Steel Mesh ◽  
Overall Water Splitting

Efficient electrocatalytic overall water splitting is achieved with commercially-available and low-cost nickel foam and stainless steel mesh as cathode and anode electrodes.

A Co-doped Ni–Fe mixed oxide mesoporous nanosheet array with low overpotential and high stability towards overall water splitting

2018 ◽  
Vol 6 (1) ◽  
pp. 167-178 ◽  
Author(s):  
Zhengcui Wu ◽  
Xia Wang ◽  
Jiansong Huang ◽  
Feng Gao
Keyword(s):  
Water Splitting ◽  
Mixed Oxide ◽  
High Stability ◽  
Ni Foam ◽  
Highly Efficient ◽  
Overall Water Splitting ◽  
Nanosheet Array ◽  
Low Overpotential ◽  
Co Doped

A Co-doped NiO/NiFe2O4 mesoporous nanosheet array on Ni foam is constructed for highly efficient overall water splitting.

Hierarchical MoS2/Ni3S2 core-shell nanofibers for highly efficient and stable overall-water-splitting in alkaline media

2018 ◽  
Vol 10 ◽  
pp. 214-221 ◽  
Author(s):  
Faze Wang ◽  
Hao Wu ◽  
Hong Sun ◽  
Li Ma ◽  
Wenzhong Shen ◽  
...  
Keyword(s):  
Water Splitting ◽  
Alkaline Media ◽  
Core Shell ◽  
Highly Efficient ◽  
Overall Water Splitting
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