scholarly journals Iridium and Ruthenium Modified Polyaniline Polymer Leads to Nanostructured Electrocatalysts with High Performance Regarding Water Splitting

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 190
Author(s):  
Razik Djara ◽  
Marie-Agnès Lacour ◽  
Abdelhafid Merzouki ◽  
Julien Cambedouzou ◽  
David Cornu ◽  
...  
Keyword(s):  
Water Splitting ◽  
High Performance ◽  
Electrochemical Impedance ◽  
Cell Voltage ◽  
Linear Sweep Voltammetry ◽  
Water Electrolysis ◽  
Linear Sweep ◽  
X Ray ◽  
On Demand ◽  
New Strategy

The breakthrough in water electrolysis technology for the sustainable production of H2, considered as a future fuel, is currently hampered by the development of tough electrocatalytic materials. We report a new strategy of fabricating conducting polymer-derived nanostructured materials to accelerate the electrocatalytic hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and water splitting. Extended physical (XRD, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX)) and electrochemical (cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS)) methods were merged to precisely characterize the as-synthesized iridium and ruthenium modified polyaniline (PANI) materials and interrogate their efficiency. The presence of Ir(+III) cations during polymerization leads to the formation of Ir metal nanoparticles, while Ru(+III) induces the formation of RuO2 oxide nanoparticles by thermal treatment; they are therefore methods for the on-demand production of oxide or metal nanostructured electrocatalysts. The findings from using 0.5 M H2SO4 highlight an ultrafast electrochemical kinetic of the material PANI-Ir for HER (36 − 0 = 36 mV overpotential to reach 10 mA cm−2 at 21 mV dec−1), and of PANI-Ru for OER (1.47 − 1.23 = 240 mV overpotential to reach 10 mA cm−2 at 47 mV dec−1), resulting in an efficient water splitting exactly at its thermoneutral cell voltage of 1.45 V, and satisfactory durability (96 h).

scholarly journals From Waste to Valuable Resource: Lignin as a Sustainable Anti-Corrosion Coating

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 454 ◽  
Author(s):  
Arman Dastpak ◽  
Kirsi Yliniemi ◽  
Mariana de Oliveira Monteiro ◽  
Sarah Höhn ◽  
Sannakaisa Virtanen ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Steel Corrosion ◽  
Linear Sweep Voltammetry ◽  
Corrosion Current ◽  
Polymer Coatings ◽  
Open Circuit ◽  
Linear Sweep ◽  
Cyclic Potentiodynamic Polarization

In this study, a waste of biorefinery—lignin—is investigated as an anticorrosion coating on stainless steel. Corrosion behavior of two lignin types (hardwood beech and softwood spruce) was studied by electrochemical measurements (linear sweep voltammetry, open circuit potential, potentiostatic polarization, cyclic potentiodynamic polarization, and electrochemical impedance measurements) during exposure to simulated body fluid (SBF) or phosphate buffer (PBS). Results from linear sweep voltammetry of lignin-coated samples, in particular, demonstrated a reduction in corrosion current density between 1 and 3 orders of magnitude cf. blank stainless steel. Furthermore, results from cross cut adhesion tests on lignin-coated samples demonstrated that the best possible adhesion (grade 0) of ISO 2409 standard was achieved for the investigated novel coatings. Such findings suggest that lignin materials could transform the field of organic coatings towards more sustainable alternatives by replacing non-renewable polymer coatings.

scholarly journals Electrodeposition of Pt-Decorated Ni(OH)2/CeO2 Hybrid as Superior Bifunctional Electrocatalyst for Water Splitting

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Huanhuan Liu ◽  
Zhenhua Yan ◽  
Xiang Chen ◽  
Jinhan Li ◽  
Le Zhang ◽  
...  
Keyword(s):  
Water Splitting ◽  
Cell Voltage ◽  
Water Electrolysis ◽  
Active Species ◽  
Water Dissociation ◽  
Electronic Interaction ◽  
Bifunctional Electrocatalyst ◽  
Highly Active ◽  
A Cell ◽  
Promising Application

The facile synthesis of highly active and stable bifunctional electrocatalysts to catalyze water splitting is attractive but challenging. Herein, we report the electrodeposition of Pt-decorated Ni(OH)2/CeO2 (PNC) hybrid as an efficient and robust bifunctional electrocatalyst. The graphite-supported PNC catalyst delivers superior hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities over the benchmark Pt/C and RuO2, respectively. For overall water electrolysis, the PNC hybrid only requires a cell voltage of 1.45 V at 10 mA cm−2 and sustains over 85 h at 1000 mA cm−2. The remarkable HER/OER performances are attributed to the superhydrophilicity and multiple effects of PNC, in which Ni(OH)2 and CeO2 accelerate HER on Pt due to promoted water dissociation and strong electronic interaction, while the electron-pulling Ce cations facilitate the generation of high-valence Ni OER-active species. These results suggest the promising application of PNC for H2 production from water electrolysis.

scholarly journals Ni2P/rGO/NF Nanosheets As a Bifunctional High-Performance Electrocatalyst for Water Splitting

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 744 ◽  
Author(s):  
Jinyu Huang ◽  
Feifei Li ◽  
Baozhong Liu ◽  
Peng Zhang
Keyword(s):  
Electron Microscopy ◽  
Water Splitting ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
High Efficiency ◽  
Splitting Method ◽  
Bifunctional Catalyst ◽  
Strong Activity ◽  
X Ray ◽  
Transmission Electron

The hydrogen generated via the water splitting method is restricted by the high level of theoretical potential exhibited by the anode. The work focuses on synthesizing a bifunctional catalyst with a high efficiency, that is, a nickel phosphide doped with the reduced graphene oxide nanosheets supported on the Ni foam (Ni2P/rGO/NF), via the hydrothermal approach together with the calcination approach specific to the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The Raman, X-Ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscope (TEM), Scanning Electron Microscopy (SEM), High-Resolution Transmission Electron Microscopy (HRTEM), as well as elemental mapping, are adopted to study the composition and morphology possessed by Ni2P/rGO/NF. The electrochemical testing is performed by constructing a parallel two-electrode electrolyzer (Ni2P/rGO/NF||Ni2P/rGO/NF). Ni2P/rGO/NF||Ni2P/rGO/NF needs a voltage of only 1.676 V for driving 10 mA/cm2, which is extremely close to Pt/C/NF||IrO2/NF (1.502 V). It is possible to maintain the current density for no less than 30 hours. It can be demonstrated that Ni2P/rGO/NF||Ni2P/rGO/NF has commercial feasibility, relying on the strong activity and high stability.

Hydrothermal Synthesis and Electrocatalytic Property for H2O2 Reduction of Co3O4 Nanocubes

2011 ◽  
Vol 311-313 ◽  
pp. 477-480
Author(s):  
Zhi Ai Yang ◽  
Li Jin Feng ◽  
Xia Wang ◽  
Rong Ma ◽  
Jian Ping Sun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Process ◽  
Linear Sweep Voltammetry ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
Linear Sweep ◽  
Electrocatalytic Property ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Subscript textThe Co3O4 nanocubes were synthesized by hydrothermal process. The products are characterized in detail by multiform techniques: scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray analysis. The results show that the products are uniform nanocubes with an average crystallite size about 20-40 nm. Electrocatalytic property of the prepared Co3O4 nanocubes was characterized by linear sweep voltammetry. LSV results indicate that Co3O4 nanocubes exhibit a remarkable electrocatalytic activity for the H2O2 reduction.

Enhanced Photoelectrocatalytic Activity of Oriented Rutile TiO2 Nanorod Array Film through Nb Doping

2014 ◽  
Vol 1010-1012 ◽  
pp. 195-201
Author(s):  
Meng Lei Chang ◽  
Dong Chu Chen ◽  
Xiu Fang Ye ◽  
Xin Jun Li ◽  
Liang Peng Wu ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Linear Sweep Voltammetry ◽  
Nanorod Array ◽  
Rutile Phase ◽  
Electrode System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conductive Glass ◽  
Nb Doping ◽  
Oxidation Of Glucose

TiO2 nanorod array films with or without Nb doping grown directly on transparent conductive glass (FTO) were prepared by a facile hydrothermal method. The films were characterized by means of field emission scanning electron microscopy (FE-SEM) with energy-dispersive x-ray spectra (EDS), X-ray diffraction (XRD) and the X-ray photoelectron spectroscoy (XPS). The electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV) and transient photocurrent were investigated in a three-electrode system with TiO2 nanorod array film served as the photoanode. The photoelectrocatalytic activity of the films was evaluated by the oxidation of glucose under UV irradiation. The results show that both the pure and Nb-doped TiO2 nanorods perpendicularly grown on FTO substrate are rutile phase. The resistance of the TiO2 nanorod array photoanode is decreased significantly by Nb doping. The steady-state photocurrent (iss) for glucose oxidation at Nb-doped TiO2 nanorod array film is much higher than that at the pure one. The enhanced photoelectrocatalytic activity of the Nb-doped TiO2 nanorods could be attributed to the enhanced charge transport ability.

Electrochemical Behavior of AZ Magnesium Alloy Containing Rare Earth Element

2013 ◽  
Vol 750 ◽  
pp. 60-63
Author(s):  
Ting Ting Gu ◽  
Hong Qi Xia ◽  
Li Xin Liu ◽  
Jing Liu ◽  
Ting Qi ◽  
...  
Keyword(s):  
Rare Earth ◽  
Magnesium Alloy ◽  
Electrochemical Behavior ◽  
Electrochemical Impedance ◽  
Linear Sweep Voltammetry ◽  
Electrochemical Activity ◽  
Passive Films ◽  
Alloying Element ◽  
Linear Sweep ◽  
Surface Morphologies

The electrochemical behavior of a new magnesium alloy (AZ61) containing rare earth elements-cerium (Mg-Al-Zn-Mn-Ce alloys) was investigated in 3% NaCl electrolyte using electrochemical methods such as linear sweep voltammetry, Tafel curves and electrochemical impedance spectroscopy. Scanning electron microscopy was used to characterize the surface morphologies of magnesium and its alloys. The results shows that compared with that of the most commonly used Mg alloy–AZ61, the cerium containing magnesium alloy exhibited higher electrochemical activity, and higher corrosion resistance. The electrochemical activity of Mg-Al-Zn-Mn-Ce was higher than that of Mg and Mg-Al-Zn-Mn-Ce alloys in 3% NaCl. The corrosion resistive order decreased in the following sequence: Mg-Al-Zn-Mn-Ce > Mg-Al-Zn-Mn > Mg. The electrolytes favored anodic magnesium oxidation, but the alloying element of Ce facilitated the formation of dense passive films on alloy surfaces.

n-Type Cu2O/α-Fe2O3 Heterojunctions by Electrochemical Deposition: Tuning of Cu2O Thickness for Maximum Photoelectrochemical Performance

2018 ◽  
Vol 232 (9-11) ◽  
pp. 1551-1566 ◽  
Author(s):  
Soniya Gahlawat ◽  
Nusrat Rashid ◽  
Pravin P. Ingole
Keyword(s):  
Oxide Layer ◽  
Electrochemical Deposition ◽  
Cuprous Oxide ◽  
Electrochemical Impedance ◽  
Base Material ◽  
Morphological Characteristics ◽  
Linear Sweep Voltammetry ◽  
Photoelectrochemical Performance ◽  
Photoelectrochemical Activity ◽  
X Ray

Abstract Here, we report the enhanced photoelectrochemical performance of surface modified hematite thin films with n-type copper oxide nanostructures (Cu2O/Fe2O3) obtained through simple electrochemical deposition method. The thickness and amount of cuprous oxide layer were varied by simply changing the number of electrodeposition cycles (viz. 5, 10, 25, 50 and 100) in order to understand its thermodynamic and kinetic influence on the photoelectrochemical activity of the resultant nano-heterostructures. Structural and morphological characteristics of the obtained Cu2O/Fe2O3 films have been studied by absorption spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis. Electrochemical investigations such as linear sweep voltammetry, Mott–Schottky analysis, and electrochemical impedance spectroscopy suggested the formation of n-type Cu2O layers over the hematite films with varying charge-carrier densities, ranging from 0.56×1019 to 3.94×1019 cm−3, that varies with the number of cycles of electrochemical deposition. Besides, the thickness of deposited cuprous oxide layer is noted to alter the net electrochemical and photo-electrochemical response of the base material. An interesting, peak event was recorded for a particular thickness of the cuprous oxide layer (obtained after 25 cycles of electrochemical deposition) below and above which the efficiency of catalyst was impaired. The heterojunction obtained thus, followed well known Z-scheme and gave appreciable increment in the photocurrent response.

scholarly journals Worrisome Exaggeration of Activity of Electrocatalysts Destined for Steady-State Water Electrolysis by Polarization Curves from Transient Techniques

2022 ◽  
Author(s):  
Anantharaj Sengeni ◽  
Subrata Kundu ◽  
Suguru Noda
Keyword(s):  
Steady State ◽  
Linear Sweep Voltammetry ◽  
Water Electrolysis ◽  
Alternative Technique ◽  
Linear Sweep ◽  
Transient Techniques ◽  
Transient Nature ◽  
Steady State Responses ◽  
State Water ◽  
State Responses

Abstract Cyclic and linear sweep voltammetry techniques substantially misjudge the performance of water splitting electrocatalysts due to their transient nature that forbids the interface from reaching a steady-state. This misjudgment leads to the potentially detrimental yet unwittingly falsified data accumulation in the literature that requires immediate attention. Alternatively, sampled-current voltammetry (SCV) constructed from steady-state responses is advised to be widely adopted for screening electrocatalysts that are actually destined for steady-state operations. To show that this exaggeration is universal, a well-characterized activated SS, coprecipitated Co(OH)2, and Pt foil electrodes are studied for OER and HER in 1.0 M KOH. The results urge that it is time to adopt a relatively more precise alternative technique such as SCV.

scholarly journals Corrosion Behavior of a Pyrite and Arsenopyrite Galvanic Pair in the Presence of Sulfuric Acid, Ferric Ions and HQ0211 Bacterial Strain

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 169 ◽  
Author(s):  
Jia-Ning Xu ◽  
Wen-Ge Shi ◽  
Peng-Cheng Ma ◽  
Liang-Shan Lu ◽  
Gui-Min Chen ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Linear Sweep Voltammetry ◽  
Open Circuit ◽  
Ferric Ions ◽  
Linear Sweep ◽  
Gold Ores ◽  
Electrochemical Testing ◽  
Tafel Curve

In this paper, the galvanic effect of pyrite and arsenopyrite during the leaching pretreatment of gold ores was determined with the use of electrochemical testing (open circuit potential, linear sweep voltammetry, Tafel, and electrochemical impedance spectroscopy (EIS)) and frontier orbit calculations. The results show that (i) the linear sweep voltammetry curve and Tafel curve of the galvanic pair are similar to those of arsenopyrite, (ii) the corrosion behavior of the galvanic pair is consistent with that of arsenopyrite, and (iii) the galvanic effect promotes the corrosion of arsenopyrite by simultaneously increasing the cathode and anode currents and reducing oxidation resistance. The frontier orbit calculation explains the principle of the galvanic effect of pyrite and arsenopyrite from the view of quantum mechanics.

scholarly journals Effect of Morphology on the Photoelectrochemical Activity of TiO2 Self-Organized Nanotube Arrays

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 279 ◽  
Author(s):  
Houda Ennaceri ◽  
Kristina Fischer ◽  
Kevin Hanus ◽  
Abdelkrim Chemseddine ◽  
Andrea Prager ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Tube Wall ◽  
Linear Sweep Voltammetry ◽  
Photocurrent Density ◽  
Tio2 Nanotube ◽  
Geometrical Parameters ◽  
Linear Sweep ◽  
Photoelectrochemical Activity ◽  
Self Organized ◽  
Anodization Process

In the present work, highly ordered titanium dioxide (TiO2) nanotube anodes were grown using a rapid anodization process. The photoelectrochemical performances of these electrodes strongly depend on the anodization conditions. Parameters such as electrolyte composition, anodization potential and anodization time are shown to affect the geometrical parameters of TiO2 nanotubes. The optimal anodization parameters are determined by photocurrent measurements, linear sweep voltammetry and electrochemical impedance spectroscopy. The thickness of the tube wall and its homogeneity is shown to strongly depend on the anodization potential, and the formation mechanism is discussed. This study permits the optimization of the photocurrent density and contributes to further improvement of the photoelectrochemical water-splitting performance of TiO2 nanotube photoelectrodes.

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