Facile Synthesis of Gold-Supported Thin Film of Cobalt Oxide via AACVD for Enhanced Electrocatalytic Activity in Oxygen Evolution Reaction

Ehsan, Muhammad Ali; Aziz, Md. Abdul; Rehman, Abdul; Hakeem, Abbas Saeed; Qasem, Mohammed Ameen Ahmed; Saadi, Omar Waqas

doi:10.1149/2.0051812jss

Cited by 10 publications

(9 citation statements)

References 63 publications

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“…Thin films of bimetallic Pd–CoO were fabricated using aerosol assisted chemical vapor deposition (AACVD) setup as described in our previous works 24 , 25 , 29 – 31 . The chemicals used in this work; Co(III) acetylacetonate Co(acac) 3 , palladium(II) acetylacetonate Pd (acac) 2, and toluene were obtained from Sigma Aldrich and were used as received.…”

Section: Methodsmentioning

confidence: 99%

“…However, this method requires the bulk of precious metals as the support, which also lacks the desired porosity and contact points to define the real synergy. Our group has also developed cobalt oxide films using this strategy but not over the bulk metal, rather over a 50 nm thick layer of metal evaporated gold 25 , with better synergic effects. Loading the precious metal nanoparticles into cobalt oxide nanostructures and films is another approach for obtaining the composites.…”

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confidence: 99%

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Synergistic effects in bimetallic Pd–CoO electrocatalytic thin films for oxygen evolution reaction

Ehsan

Hakeem

Rehman

2020

Sci Rep

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Bimetallic catalysts due to the synergistic effects often outperform their single-component counterparts while exhibiting structure and composition-dependent enhancement in active sites, thereby having the potential to improve the current density and over-potential parameters in the water oxidation reaction. Herein, we demonstrate a simple and rapid, yet highly efficient method to fabricate Pd-CoO films of immaculate homogeneity as characterized using different imaging and spectroscopic techniques. The SEM images revealed that the films were composed of bimetallic spherical granules wherein both metals were uniformly distributed in an atomic ratio of ~ 1:1. The time-dependent investigations of the film fabrication behavior demonstrated that the films formed in shorter deposition times (1-2 h) display more porous character, allowing better access to the reaction centers. This character was transcribed into their enhanced electrocatalytic performance toward the oxygen evolution reaction (OER). Using this specific bimetallic formulation, we could attain a low over-potential of 274 mV for a current density of 10 mA cm −2 , whereas the high current density value of > 200 mA cm −2 was achieved while still under 600 mV of over-potential. The cycling and current generation stability was also found to be sufficiently high, which can only be attributed to the facile electron transfer processes and a higher number of active sites available in homogeneous bimetallic films. Electrocatalytic water oxidation is an extensively studied reaction due to its importance in industrial water splitting for hydrogen-based economy 1. Such a non-reliance on fossil fuels can enforce a change towards a more sustainable society with a lesser burden of pollution on the climate. However, this anodic reaction is a limiting factor in the large scale electrolysis of water 2. The process includes four proton-coupled electron transfers and two oxygen atoms bonding together, making it electrochemically sluggish because of high energy demands 3. The result is the high over-potentials, and low current densities, whereas the target is to achieve an industrial standard current density of more than 100 mA cm −2 with the least over-potential possible 4. Thus, the materials with the ability to catalyze this reaction are of high significance not only for water splitting based hydrogen generation 5,6 , but also for oxygen evolution reactions (OER) in metal-air batteries 7,8 , or other oxidation reactions such as the oxidation of CO 9 for the purification of hydrogen fuel obtained via currently accustomed fossil fuels based production. While the oxides of Iridium and Ruthenium still remains the benchmark in catalyzing this process 10 , the search for the earth-abundant low-cost substitute continues 5,11. An illustrative outcome of this search is the oxides of transition metals (e.g., Ni, Co, Fe) showing structures and compositions similar to the active center of spinels or other oxygen-evolving complexes 12-14. From these materials, the oxides of cobalt, espec...

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Synergistic effects in bimetallic Pd–CoO electrocatalytic thin films for oxygen evolution reaction

Ehsan

Hakeem

Rehman

2020

Sci Rep

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“…The anodic OER overpotential (η) was also estimated for all the prepared electrodes using the following equation. [15] h…”

Section: Electrocatalytic Propertiesmentioning

confidence: 99%

“…[1][2][3][4][5][6] Suitable electrocatalysts can play a significant role in minimizing the energy/overpotential, i. e., cost for water oxidation. In the last two decades, there has been significant research on the development of electrocatalysts, e. g., precious and nonprecious metal or metal oxide nanoparticles, e. g., Au, [7][8][9] Pt, [10] RuO x , [11] IrO x , [12] CoO x , [13][14][15][16] MnO x , [17,18] NiO x [19,20] nanoparticles, and metal complexes, e. g., copper and cobalt complexes. [21,22] Among the mentioned electrode materials, CoO x including Co 3 O 4 and CoO, have been investigated vigorously due to its high efficiency, low cost, low toxicity, and wide availability all over the world.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Oxygen Evolution via Electrochemical Water Oxidation using Conducting Polymer and Nanoparticle Composites

Mahfoz

Aziz

Shah

et al. 2020

Chemistry An Asian Journal

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Nano-Co 3 O 4 was used for electrocatalytic water oxidation due to its promising features of better performance and low cost. An enhanced electrochemical water oxidation performance of the nanoparticles can be achieved by mixing them with other types of highly conductive nano/microstructured materials. Conductive polymers would be one of the candidates to achieve this goal. Here, we report our recently developed nano-Co 3 O 4 and polypyrrole composites for enhanced electrochemical water oxidation. We chose polypyrrole as a support of nano-Co 3 O 4 to obtain highly active sites of nano-Co 3 O 4 with high conductivity. Morphological and chemical characterization of the prepared materials were performed using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). After immobilizing them individually on fluorine doped tin oxide (FTO) substrate, their electrocatalytic properties toward water oxidation were investigated. The optimum composite materials showed significantly higher electrocatalytic properties compared to that of pure nano-Co 3 O 4 and polypyrrole. Electrochemical impedance studies indicated that the composite materials possess significantly less electron transfer resistance toward water oxidation reaction compared to that of only polypyrrole or nano-Co 3 O 4 , while the higher double-layer capacitance and polarization resistance values obtained from fitting of the impedance data represent the faster electrode kinetics in the composite electrocatalyst. Due to the synergetic effect, the optimum nano-Co 3 O 4 and polypyrrole composites could be represent a novel and promising material for water oxidation.

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“…Various metal/metal oxide films have thus been fabricated for a range of applications with time-dependent morphologies and enhanced photo/electrocatalytic performance. 27−29 Thus, it was envisaged that a similar protocol can be followed to generate films of Co–V mixed oxide for effective and stable water oxidation reaction.…”

Section: Introductionmentioning

confidence: 99%

Direct Deposition of Amorphous Cobalt–Vanadium Mixed Oxide Films for Electrocatalytic Water Oxidation

et al. 2019

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Efficiency of water oxidation catalysts in terms of overpotential, current density, and voltage stability over time with facile methods of their fabrication remains a key challenge in developing competent mechanisms of storing energy in the form of green hydrogen fuels. In this work, a rapid one-step aerosol-assisted chemical vapor deposition (AACVD) method is employed to synthesize amorphous and highly active cobalt–vanadium mixed oxide catalysts (CoVO x ) directly over fluorine-doped tin oxide (FTO) substrates. Morphological and structural characterizations made by field emission scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy techniques revealed the formation of pure-phase amorphous films with a gradual variation of topography as a function of deposition time. Of these films, the most active film (CoVO x -20) was obtained in 20 min deposition, showing a spongy networking of interwoven nanofibers with a homogeneous distribution of 3–4 nm pores, achieving an overpotential of 308 mV at 10 mA/cm 2 current density. A much higher current density of 175 mA/cm 2 could be achieved just at 380 mV of overpotential with Tafel slope as low as 62 mV/dec for this whole range while exhibiting long-term stability. Mass activity, electrochemical impedance spectroscopy data, and the estimation of electrochemically active surface area all endorsed this high catalytic performance of CoVO x -20, which is unprecedented for a low-cost, upscalable, and relatively less conductive substrate such as FTO used here. Our findings, thus, not only highlight the benefits of using AACVD in preparing two-dimensional amorphous catalysts but also prove the high efficiency of CoVO x materials thus obtained, as outlined in a plausible reaction mechanism.

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Facile Synthesis of Gold-Supported Thin Film of Cobalt Oxide via AACVD for Enhanced Electrocatalytic Activity in Oxygen Evolution Reaction

Cited by 10 publications

References 63 publications

Synergistic effects in bimetallic Pd–CoO electrocatalytic thin films for oxygen evolution reaction

Synergistic effects in bimetallic Pd–CoO electrocatalytic thin films for oxygen evolution reaction

Enhanced Oxygen Evolution via Electrochemical Water Oxidation using Conducting Polymer and Nanoparticle Composites

Direct Deposition of Amorphous Cobalt–Vanadium Mixed Oxide Films for Electrocatalytic Water Oxidation

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