scholarly journals Fe2O3 Blocking Layer Produced by Cyclic Voltammetry Leads to Improved Photoelectrochemical Performance of Hematite Nanorods

Surfaces ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 131-144 ◽  
Author(s):  
Mahshid Poornajar ◽  
Nhat Nguyen ◽  
Hyo-Jin Ahn ◽  
Markus Büchler ◽  
Ning Liu ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Bulk Material ◽  
Anodic Oxide ◽  
Photocurrent Density ◽  
Iron Film ◽  
Blocking Layer ◽  
Photoelectrochemical Performance ◽  
Onset Potential ◽  
Surface And Interface ◽  
Sputter Deposited

Hematite is a low band gap, earth abundant semiconductor and it is considered to be a promising choice for photoelectrochemical water splitting. However, as a bulk material its efficiency is low because of excessive bulk, surface, and interface recombination. In the present work, we propose a strategy to prepare a hematite (α-Fe2O3) photoanode consisting of hematite nanorods grown onto an iron oxide blocking layer. This blocking layer is formed from a sputter deposited thin metallic iron film on fluorine doped tin oxide (FTO) by using cyclic voltammetry to fully convert the film into an anodic oxide. In a second step, hematite nanorods (NR) are grown onto the layer using a hydrothermal approach. In this geometry, the hematite sub-layer works as a barrier for electron back diffusion (a blocking layer). This suppresses recombination, and the maximum of the incident photon to current efficiency is increased from 12% to 17%. Under AM 1.5 conditions, the photocurrent density reaches approximately 1.2 mA/cm2 at 1.5 V vs. RHE and the onset potential changes to 0.8 V vs. RHE (using a Zn-Co co-catalyst).

scholarly journals Design an Epoxy Coating with TiO2/GO/PANI Nanocomposites for Enhancing Corrosion Resistance of Q235 Carbon Steel

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2629
Author(s):  
Shimin Chen ◽  
Bo Li ◽  
Rengui Xiao ◽  
Huanhu Luo ◽  
Siwu Yu ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Photocurrent Density ◽  
Photoelectrochemical Performance ◽  
Q235 Steel ◽  
Protective Barrier ◽  
Barrier Coating ◽  
Pani Composite ◽  
Steel Protection ◽  
Q235 Carbon Steel

In this work, a ternary TiO2/Graphene oxide/Polyaniline (TiO2/GO/PANI) nanocomposite was synthesized by in situ oxidation and use as a filler on epoxy resin (TiO2/GO/PANI/EP), a bifunctional in situ protective coating has been developed and reinforced the Q235 carbon steel protection against corrosion. The structure and optical properties of the obtained composites are characterized by XRD, FTIR, and UV–vis. Compared to bare TiO2 and bare Q235, the TiO2/GO/PANI/EP coating exhibited prominent photoelectrochemical properties, such as the photocurrent density increased 0.06 A/cm2 and the corrosion potential shifted from −651 mV to −851 mV, respectively. The results show that the TiO2/GO/PANI nanocomposite has an extended light absorption range and the effective separation of electron-hole pairs improves the photoelectrochemical performance, and also provides cathodic protection to Q235 steel under dark conditions. The TiO2/GO/PANI/EP coating can isolate the Q235 steel from the external corrosive environment, and may generally be regarded a useful protective barrier coating to metallic materials. When the TiO2/GO/PANI composite is dispersed in the EP, the compactness of the coating is improved and the protective barrier effect is enhanced.

Photoelectrochemical water splitting at low applied potential using a NiOOH coated codoped (Sn, Zr) α-Fe2O3 photoanode

2015 ◽  
Vol 3 (11) ◽  
pp. 5949-5961 ◽  
Author(s):  
Andebet Gedamu Tamirat ◽  
Wei-Nien Su ◽  
Amare Aregahegn Dubale ◽  
Hung-Ming Chen ◽  
Bing-Joe Hwang
Keyword(s):  
Water Splitting ◽  
Photoelectrochemical Water Splitting ◽  
Applied Potential ◽  
Photoelectrochemical Performance ◽  
Onset Potential

We synthesized a NiOOH decorated codoped (Sn, Zr) α-Fe2O3 photoanode that results in enhanced photoelectrochemical performance and drastically lower onset potential.

Engineering the kinetics and interfacial energetics of Ni/Ni–Mo catalyzed amorphous silicon carbide photocathodes in alkaline media

2016 ◽  
Vol 4 (18) ◽  
pp. 6842-6852 ◽  
Author(s):  
Ibadillah A. Digdaya ◽  
Paula Perez Rodriguez ◽  
Ming Ma ◽  
Gede W. P. Adhyaksa ◽  
Erik C. Garnett ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Amorphous Silicon ◽  
Photocurrent Density ◽  
Alkaline Media ◽  
Photoelectrochemical Performance ◽  
Amorphous Silicon Carbide ◽  
Interfacial Energetics

The photoelectrochemical performance of a-SiC photocathodes was enhanced by using a Ni/Ni-Mo dual-catalyst resulting in a significant increase of photocurrent density of −14 mA cm−2 at 0 V vs. RHE.

scholarly journals Vibrational Spectroscopy of Boron Nitride at High Temperatures and Pressures

1989 ◽  
Vol 162 ◽  
Author(s):  
Gregory Y. Exarhos ◽  
Nancy J. Hess
Keyword(s):  
Boron Nitride ◽  
Bulk Material ◽  
Hexagonal Phase ◽  
Bulk Materials ◽  
Lattice Thermal Expansion ◽  
Line Frequency ◽  
Nitride Coatings ◽  
Scattering Measurements ◽  
Sputter Deposited ◽  
Inherent Strain

ABSTRACTRaman scattering measurements are used to distinguish between amorphous and crystalline phases in sputter deposited boron nitride coatings and bulk materials. Changes in vibrational line frequency and linewidth can be attributed to differences in particle size or inherent strain which can be quantified from pressure-dependent measurements of the bulk material. The response of the Raman-allowed E2g modes (hexagonal phase) to temperature is described by a forced dampeg harmonic oscillator model from which the intra- and interplanar lattice thermal expansion can be estimated.

Co–Mo–Se ternary chalcogenide thin film coated p-Si photocathode for efficient solar hydrogen production

2020 ◽  
pp. 2151002
Author(s):  
Cihan Kuru
Keyword(s):  
Thin Film ◽  
Hydrogen Production ◽  
Photocurrent Density ◽  
Superior Performance ◽  
Great Promise ◽  
High Catalytic Activity ◽  
Hydrogen Electrode ◽  
Onset Potential ◽  
Ternary Chalcogenide ◽  
Chalcogenide Thin Film

Photoelectrochemical (PEC) water splitting holds a great promise for clean and sustainable hydrogen production. In this study, the PEC performance of Co–Mo–Se ternary chalcogenide thin film coated Si photocathodes is investigated. The Co–Mo–Se films with various Co/Mo atomic ratios were prepared by thermal selenization of sputter deposited Co–Mo alloy films. Among the photocathodes, the Co–Mo–Se (3:10)/[Formula: see text]-Si surpasses the PEC performance of the MoSe2/[Formula: see text]-Si with an onset potential of +124 mV vs. reversible hydrogen electrode (RHE), a photocurrent density of −22.68 mA/cm2 at zero overpotential and good stability over 6 h period of test. The superior performance of the Co–Mo–Se (3:10)/[Formula: see text]-Si is ascribed to the high catalytic activity of the film in hydrogen evolution reaction (HER) and efficient collection of photogenerated charge carriers. Such ternary chalcogenide thin films offer exciting opportunities for many applications in which the physicochemical properties can be tuned by changing the relative amount of the solute atoms.

Preparation and photoelectrochemical performance of nano Bi2S3–TiO2 composites

2018 ◽  
Vol 11 (03) ◽  
pp. 1850055 ◽  
Author(s):  
Senlin Li ◽  
Jinliang Huang ◽  
Xiangmei Ning ◽  
Yongchao Chen ◽  
Qingkui Shi
Keyword(s):  
Solvothermal Method ◽  
Composite Films ◽  
Great Influence ◽  
Photocurrent Density ◽  
Tetrabutyl Titanate ◽  
X Ray Diffraction ◽  
Photoelectrochemical Performance ◽  
X Ray ◽  
External Bias ◽  
Transmission Electron

TiO2 nanorod (NR) arrays were prepared on FTO by the simple hydrothermal synthesizing method. On this basis, a layer of Bi2S3 quantum dots (QDs) was covered on the surface of TiO2 NRs array by solvothermal method, by which the Nano Bi2S3/TiO2 NRs composites films were obtained. The phase structure, morphologies, optical absorptions and photoelectrochemical (PEC) properties of the as-prepared materials were characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), High Resolution Transmission Electron Microscopy (HRTEM), Ultraviolet–visible spectroscopy (UV-Vis), Photoluminescence (PL) and electrochemical workstation. The results indicate that the concentration of tetrabutyl titanate (TBT) has a great influence on the morphology of the film, with the increase of TBT content, the array of TiO2 NRs changed from loose to tight, and the thin films were cracked when the TBT volume is up to 0.7[Formula: see text]mL; The absorption of the TiO2 NRs array film to the visible light is enhanced significantly when sensitized with Bi2S3 and the absorption wavelength is increased from 400[Formula: see text]nm to 800[Formula: see text]nm. Compared with the pure TiO2, the fluorescence intensity of the TiO2/Bi2S3 NRs is weakened, and there is no obvious fluorescence diffraction peak. Under the irradiation of standard (AM1.5[Formula: see text]G 100[Formula: see text]mW/cm[Formula: see text], the photocurrent density of the composite film increased significantly. When the external bias voltage is 1.2[Formula: see text]V, the current density of the composite films is five times of that of the pure TiO2.

A Voltammetric Investigation of AC Corrosion Phenomena at an Aluminum Electrode in Hydrochloric Acid

CORROSION ◽  
1984 ◽  
Vol 40 (12) ◽  
pp. 644-649 ◽  
Author(s):  
W. Michael Moore ◽  
Chia-Tien Chen ◽  
George A. Shirn
Keyword(s):  
Cyclic Voltammetry ◽  
High Speed ◽  
Solution Temperature ◽  
Aluminum Electrode ◽  
Half Cycle ◽  
Potential Sweep ◽  
Cathodic Potential ◽  
Square Wave ◽  
Onset Potential ◽  
Hcl Concentration

Abstract The electrochemical behavior of Al in HCl has been studied by cyclic voltammetry, square-wave chronoamperometry, and square-wave chronopotentiometry. High speed cyclic voltammetry was studied thoroughly, and the effects of temperature, HCl concentration, potential sweep rate, and cathodic potential limit were examined. Relevant parameters that can be determined from the cyclic voltammetric i-V curve include the breakdown and protection potentials for Al, the onset potential for hydrogen evolution, and the magnitude of the anodic and cathodic currents. The degree of passivity, which is reflected in the anodic breakdown potential and the magnitude of the anodic current, decreased with increasing solution temperature and HCl concentration, and increased with higher sweep rates. The nature of the Al passivation that occurs during the cathodic half-cycle depends on the cathodic potential limit. These processes and their relationship to the voltammetric curves are discussed in detail.

A study on the surface and interface of porous anodic oxide film of aluminium

1996 ◽  
Vol 29 (10) ◽  
pp. 2534-2538 ◽  
Author(s):  
Xu Tao ◽  
Qi Shangkui ◽  
Zhao Jiazheng ◽  
Chen Jianmin
Keyword(s):  
Oxide Film ◽  
Anodic Oxide ◽  
Anodic Oxide Film ◽  
Surface And Interface

scholarly journals Direct growth of uniform carbon nitride layers with extended optical absorption towards efficient water-splitting photoanodes

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiani Qin ◽  
Jesús Barrio ◽  
Guiming Peng ◽  
Jonathan Tzadikov ◽  
Liel Abisdris ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Water Splitting ◽  
Carbon Nitride ◽  
Photophysical Properties ◽  
Photocurrent Density ◽  
Nitride Layer ◽  
Universal Method ◽  
Intimate Contact ◽  
Faradaic Efficiency ◽  
Onset Potential

Abstract A general synthesis of carbon nitride (CN) films with extended optical absorption, excellent charge separation under illumination, and outstanding performance as a photoanode in water-splitting photoelectrochemical cells is reported. To this end, we introduced a universal method to rapidly grow CN monomers directly from a hot saturated solution on various substrates. Upon calcination, a highly uniform carbon nitride layer with tuned structural and photophysical properties and in intimate contact with the substrate is obtained. Detailed photoelectrochemical and structural studies reveal good photoresponse up to 600 nm, excellent hole extraction efficiency (up to 62%) and strong adhesion of the CN layer to the substrate. The best CN photoanode demonstrates a benchmark-setting photocurrent density of 353 µA cm−2 (51% faradaic efficiency for oxygen), and external quantum yield value above 12% at 450 nm at 1.23 V versus RHE in an alkaline solution, as well as low onset potential and good stability.

Loading the FeNiOOH cocatalyst on Pt-modified hematite nanostructures for efficient solar water oxidation

2016 ◽  
Vol 18 (15) ◽  
pp. 10453-10458 ◽  
Author(s):  
Jiujun Deng ◽  
Xiaoxin Lv ◽  
Hui Zhang ◽  
Binhua Zhao ◽  
Xuhui Sun ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Photocurrent Density ◽  
Onset Potential ◽  
Solar Water ◽  
Solar Water Oxidation

A significant cathodic shift of the onset potential and an enhancement of the photocurrent density can be found in the FeNiOOH-decorated hematite photoanode.

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