Hierarchical iron molybdate nanostructure array for efficient water oxidation through optimizing electron density

2021 ◽  
Vol 57 (29) ◽  
pp. 3563-3566
Author(s):  
Jun-Jun Zhang ◽  
Chun-Ming Yang ◽  
Chang-Qing Jin ◽  
Wei-Wei Bao ◽  
Rui-Hua Nan ◽  
...  
Keyword(s):  
Electron Density ◽  
Current Density ◽  
Water Oxidation ◽  
Electron Structure ◽  
Iron Molybdate ◽  
Nanostructure Array ◽  
Excellent Stability

We report the tuning of the iron molybdate electron structure via a coupled interface between the catalytic centers and substrate. The developed FeMoO4 catalysts can provide a 50 mA cm−2 current density at 1.506 V vs. RHE with excellent stability.

scholarly journals Coordination modulation of iridium single-atom catalyst maximizing water oxidation activity

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Zhanwu Lei ◽  
Wenbin Cai ◽  
Yifei Rao ◽  
Kuan Wang ◽  
Yuyuan Jiang ◽  
...  
Keyword(s):  
High Activity ◽  
Current Density ◽  
Water Oxidation ◽  
Distribution Density ◽  
High Surface ◽  
Single Atom ◽  
Surface Distribution ◽  
Oxidation Activity ◽  
Nanosheet Arrays ◽  
A Current

AbstractSingle-atom catalysts (SACs) have attracted tremendous research interests in various energy-related fields because of their high activity, selectivity and 100% atom utilization. However, it is still a challenge to enhance the intrinsic and specific activity of SACs. Herein, we present an approach to fabricate a high surface distribution density of iridium (Ir) SAC on nickel-iron sulfide nanosheet arrays substrate (Ir1/NFS), which delivers a high water oxidation activity. The Ir1/NFS catalyst offers a low overpotential of ~170 mV at a current density of 10 mA cm−2 and a high turnover frequency of 9.85 s−1 at an overpotential of 300 mV in 1.0 M KOH solution. At the same time, the Ir1/NFS catalyst exhibits a high stability performance, reaching a lifespan up to 350 hours at a current density of 100 mA cm−2. First-principles calculations reveal that the electronic structures of Ir atoms are significantly regulated by the sulfide substrate, endowing an energetically favorable reaction pathway. This work represents a promising strategy to fabricate high surface distribution density single-atom catalysts with high activity and durability for electrochemical water splitting.

A cobalt-borate nanosheet array: an efficient and durable non-noble-metal electrocatalyst for water oxidation at near neutral pH

2017 ◽  
Vol 5 (16) ◽  
pp. 7305-7308 ◽  
Author(s):  
Libin Yang ◽  
Danni Liu ◽  
Shuai Hao ◽  
Rongmei Kong ◽  
Abdullah M. Asiri ◽  
...  
Keyword(s):  
High Activity ◽  
Noble Metal ◽  
Current Density ◽  
Water Oxidation ◽  
Catalytic Current ◽  
Neutral Ph ◽  
Nanosheet Array ◽  
Ti Mesh ◽  
Catalyst Electrode

As a durable catalyst electrode, a cobalt-borate nanosheet array on a Ti mesh shows high activity for water oxidation in 0.1 M K-Bi (pH: 9.2), achieving a geometrical catalytic current density of 10 mA cm−2 at an overpotential of 469 mV.

INTERFACE ELECTRON STRUCTURE OFTiC–NiAlCOMPOSITES

2012 ◽  
Vol 19 (05) ◽  
pp. 1250056
Author(s):  
X.-F. TIAN ◽  
W.-K. ZHANG ◽  
Y. QI
Keyword(s):  
Electron Density ◽  
Valence Electron ◽  
Electron Structure ◽  
Matrix Composites ◽  
Communication Interface ◽  
Valence Electron Structure ◽  
Valence Electron Density ◽  
Intermetallic Matrix ◽  
Intermetallic Matrix Composites ◽  
Set Up

Intermetallic matrix composites reinforced with ceramic particles such as TiC have received increasing attention in recent years due to the combined potential of ceramics and intermetallics to give a desirable balance of properties. But an understanding of some experimental results presented elsewhere has remained elusive. In this communication, interface valence electron structure of TiC–NiAl composites was set up on the basis of Pauling's nature of the chemical bond, and valence electron density ρ of different atomic states TiC and NiAl composites in various planes was determined. From the viewpoint of biphase interface electron density continuing, the corresponding experimental phenomena are explained.

Hierarchical CoS2/Ni3S2/CoNiOx nanorods with favorable stability at 1 A cm−2 for electrocatalytic water oxidation

2019 ◽  
Vol 55 (11) ◽  
pp. 1564-1567 ◽  
Author(s):  
Husileng Lee ◽  
Xiujuan Wu ◽  
Qilun Ye ◽  
Xingqiang Wu ◽  
Xiaoxiao Wang ◽  
...  
Keyword(s):  
Current Density ◽  
Water Oxidation ◽  
Oxidation Catalyst ◽  
A Current

A hierarchical 3D CoS2/Ni3S2/CoNiOx water oxidation catalyst can maintain a current density of 1 A cm−2 for one week in 30% KOH solution with a slight increase of the overpotential.

Many-Electron Problem in Terms of the Density: From Thomas–Fermi to Modern Density-Functional Theory

2003 ◽  
Vol 02 (02) ◽  
pp. 301-322 ◽  
Author(s):  
Manoj K. Harbola ◽  
Arup Banerjee
Keyword(s):  
Density Functional Theory ◽  
Perturbation Theory ◽  
Electron Density ◽  
Current Density ◽  
Density Functional ◽  
Electron System ◽  
Time Dependent ◽  
Functional Theory ◽  
Thomas Fermi ◽  
Alkali Metal Clusters

In this paper we focus on the use of electron density and current-density as basic variables in describing a many-electron system. We start with a discussion of the seminal Thomas–Fermi theory and its extension by Bloch for time-dependent hamiltonians. We then present modern density-functional theory (for both time-independent and time-dependent hamiltonians) and approximations involved in implementing it. Also discussed is perturbation theory in terms of electron density and its use for calculating various response properties and related quantities. In particular, van der Waals coefficient C6 is calculated using density and current density in time-dependent perturbation theory. Throughout the paper, results for alkali-metal clusters are presented to demonstrate the strength of density-based theories.

scholarly journals Low-cost CoFe2O4/biomass carbon hybrid from metal-enriched sulfate reducing bacteria as an electrocatalyst for water oxidation

RSC Advances ◽  
2018 ◽  
Vol 8 (40) ◽  
pp. 22799-22805 ◽  
Author(s):  
Songhu Bi ◽  
Jingde Li ◽  
Qin Zhong ◽  
Chuntan Chen ◽  
Qiyi Zhang ◽  
...  
Keyword(s):  
Current Density ◽  
Water Oxidation ◽  
Low Cost ◽  
Sulfate Reducing Bacteria ◽  
Biomass Carbon ◽  
Tafel Slope ◽  
Sulfate Reducing ◽  
Reducing Bacteria ◽  
A Current

A low-cost CoFe2O4/biomass carbon (CFO@BC/Zn) hybrid from Co-enriched Sulfate Reducing Bacteria (Co-SRB) as an electrocatalyst for OER. The electrocatalyst exhibits a low potential of 1.53 V at a current density 10 mA cm−2 and Tafel slope of 86 mV dec−1.

Hetero-structured Iron Molybdate Nanoparticles: Synthesis, Characterization and Photocatalytic Application

2020 ◽  
Vol 18 (2) ◽  
Author(s):  
Jan Nisar ◽  
Sohaib Hassan ◽  
Muhammad Iftikhar Khan ◽  
Munawar Iqbal ◽  
Arif Nazir ◽  
...  
Keyword(s):  
Complex Structure ◽  
Precipitation Process ◽  
Alkaline Ph ◽  
Solution Ph ◽  
Iron Molybdate ◽  
Photo Degradation ◽  
Photocatalytic Application ◽  
Initial Ph ◽  
Co Precipitation ◽  
Excellent Stability

AbstractThis study focuses on the synthesis of iron molybdate [Fe2(MoO4)3] nanoparticles (NPs) using simple co-precipitation process. The catalyst synthesized was characterized by advanced instrumental techniques such as XRD, SEM, EDX, TGA and FTIR, which confirmed the successful synthesis of NPs. Organic compound Rhodamine B (Rh. B) dye was selected for photo-degradation due to its complex structure and carcinogenic nature. Results exhibited that at neutral pH, the synthesized catalyst is highly effective for the degradation of Rh. B. For 20 mg/L initial concentration with an initial pH of 6.7, the degradation efficiency of Rh. B reaches 98  % within 180 min. Furthermore, the solution pH (1 to 11) affects the catalytic activity. This indicates that at neutral and/or alkaline pH, the usage of iron molybdate overwhelms the efficiency of Fenton-like reaction. It has been observed that Fe2(MoO4)3 showed excellent stability as after recycling it for 9 times its performance remained effective. Based on these data, the synthesized catalyst could be conveniently employed for degradation of toxic pollutants.

scholarly journals Scalable, highly stable Si-based metal-insulator-semiconductor photoanodes for water oxidation fabricated using thin-film reactions and electrodeposition

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Soonil Lee ◽  
Li Ji ◽  
Alex C. De Palma ◽  
Edward T. Yu
Keyword(s):  
Thin Film ◽  
Current Density ◽  
Water Oxidation ◽  
Metal Catalyst ◽  
Saturation Current ◽  
Metal Insulator ◽  
Metal Insulator Semiconductor ◽  
Onset Potential ◽  
Solar Water Splitting ◽  
Saturation Current Density

AbstractMetal-insulator-semiconductor (MIS) structures are widely used in Si-based solar water-splitting photoelectrodes to protect the Si layer from corrosion. Typically, there is a tradeoff between efficiency and stability when optimizing insulator thickness. Moreover, lithographic patterning is often required for fabricating MIS photoelectrodes. In this study, we demonstrate improved Si-based MIS photoanodes with thick insulating layers fabricated using thin-film reactions to create localized conduction paths through the insulator and electrodeposition to form metal catalyst islands. These fabrication approaches are low-cost and highly scalable, and yield MIS photoanodes with low onset potential, high saturation current density, and excellent stability. By combining this approach with a p+n-Si buried junction, further improved oxygen evolution reaction (OER) performance is achieved with an onset potential of 0.7 V versus reversible hydrogen electrode (RHE) and saturation current density of 32 mA/cm2 under simulated AM1.5G illumination. Moreover, in stability testing in 1 M KOH aqueous solution, a constant photocurrent density of ~22 mA/cm2 is maintained at 1.3 V versus RHE for 7 days.

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