Cyclic voltammetry - A promising approach towards improving photoelectrochemical activity of hematite

Arzaee, Nurul Affiqah; Noh, Mohamad Firdaus Mohamad; Halim, Azhar Abdul; Rahim, M.; Ita, Nur Suraya Haziqah Mohd; Mohamed, Nurul Aida; Nasir, Siti Nur Farhana Mohd; Ismail, Aznan Fazli; Teridi, Mohd Asri Mat

doi:10.1016/j.jallcom.2020.156757

Cited by 17 publications

(10 citation statements)

References 40 publications

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“…In addition to these reflections some weaker peaks corresponding to the (012), (006), ( 113), (024), (116), and (122) planes are also observable. All the observed reflections are closely matched with the standard values (JCPDS-00-024-0072) of the inter-planar distance d for hematite [21] and are indexed to their respective Miller indices. The absence of some of the peaks may be due to very intense peaks of the substrate and slight 2θ shift for some of the peaks could be ascribed to the lattice mismatch between substrate and film which causes strain in the film lattice.…”

Section: Pxd Analysissupporting

confidence: 61%

“…V vs. RHE) is to the best of our knowledge, the highest photocurrent reported to date for any pristine (externally undoped) hematite thin film prepared by the AACVD method. By comparison, a photocurrent of 455µA cm -2 at 1.23 V vs. RHE at 450°C was reported for a nanostructured α-Fe2O3 AACVD thin film in 2014 [20], while in 2019, a current density of 585 µA cm -2 at 1.2 V vs Ag/AgCl was recorded for an AACVD hematite film [21].…”

Section: Figmentioning

confidence: 97%

“…Subsequently a current 104 density of 585 µAcm -2 at 1.23 V vs. RHE was obtained in a hematite film by using AACVD method. [21].…”

mentioning

confidence: 99%

“…1a & b) and their consequent 488 excellent light harvesting property. Despite a hole diffusion length of the order 2-4 nm [21] the tuning of the thin film 489 nanostructure substantially affects the photocurrent. The electron-hole (e-h) separation within the width of the space 490 charge layer becomes a key factor, which seems to be more pronounced for electrodes composed of films deposited at 491 higher temperature (in our case, at 525 °C).…”

mentioning

confidence: 99%

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Improved Photoelectrochemical Performance of Chemically Grown Pristine Hematite Thin Films

Qureshi

Gregory

Tahir

et al. 2021

J. Electron. Mater.

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The alpha phase of hematite (α-Fe 2 O 3 ) is one of the most promising catalysts for photoelectrochemical (PEC) water splitting amongst several photoanode materials due to its suitable bandgap and stability in aqueous solutions. The surface structure and morphology of films play pivotal roles in the enhancement of water oxidation reaction kinetics. In this work, α-Fe 2 O 3 films were produced via either spray pyrolysis (SP), chemical vapor deposition (CVD) or aerosol-assisted chemical vapor deposition (AACVD). Their structural and morphological properties were subsequently characterized by powder X-ray diffraction (PXD), scanning electron microscopy (SEM) and Raman spectroscopy. High quality thin films were best achieved by AACVD annealed at 525 ° C, possessing an average thickness of 0.75µm with 85% transmittance and an optical absorption onset at 650 nm. The results evidently showed that the thermal oxidation process achieved at 525°C eliminated undesired impurity phases such as FeO and Fe 3 O 4 and enabled the microstructure to be optimized to facilitate the generation and transport of photogenerated charge carriers. The optimized α-Fe 2 O 3 film showed a stable PEC water oxidation current density of ~1.23 mA cm -2 at 1.23 V (vs. RHE), with an onset potential of 0.76 V, under AM 1.5 irradiation. The obtained higher current density of pristine α-Fe 2 O 3 thin films obtained by AACVD method is unique and the films presented good photocurrent stability with 92% retention after 6 h. Data form electrochemical impedance spectroscopy (EIS) corroborated these results, identifying fast charge transfer kinetics with decreased resistance and an electron lifetime of 175 µs. Quantitative measurements showed that 1.2 μmol cm -2 of oxygen could be produced at the photoanode in 6 h.

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Section: Pxd Analysissupporting

confidence: 61%

Section: Figmentioning

confidence: 97%

“…Subsequently a current 104 density of 585 µAcm -2 at 1.23 V vs. RHE was obtained in a hematite film by using AACVD method. [21].…”

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Improved Photoelectrochemical Performance of Chemically Grown Pristine Hematite Thin Films

Qureshi

Gregory

Tahir

et al. 2021

J. Electron. Mater.

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“…The α-Fe 2 O 3 /Fe 3 O 4 nanoparticles modified GCE demonstrated a better current response due to the presence of electroactive species on the electrode surface. Moreover, α-Fe 2 O 3 /Fe 3 O 4 nanoparticles can act as a charge transfer medium and enhance the charge transfer process during an electrochemical reaction [ 51 , 52 ]. The introduction of α-Fe 2 O 3 /Fe 3 O 4 nanoparticles on the GCE surface facilitated the conduction pathway by exhibiting reversible behavior and possessed faster charge transfer kinetics as indicated by low Δ𝐸𝑝 values (0.16 V for α-Fe 2 O 3 and 0.21 for Fe 3 O 4 ).…”

Section: Resultsmentioning

confidence: 99%

Systematic Investigation of Structural, Morphological, Thermal, Optoelectronic, and Magnetic Properties of High-Purity Hematite/Magnetite Nanoparticles for Optoelectronics

Qureshi

Javed

et al. 2022

Nanomaterials

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Iron oxide nanoparticles, especially hematite (α-Fe2O3) and magnetite (Fe3O4) have attained substantial research interest in various applications of green and sustainable energy harnessing owing to their exceptional opto-magneto-electrical characteristics and non-toxicity. In this study, we synthesized high-purity hematite and magnetite nanoparticles from a facile top-down approach by employing a high-energy ball mill followed by ultrasonication. A systematic investigation was then carried out to explore the structural, morphological, thermal, optoelectrical, and magnetic properties of the synthesized samples. The experimental results from scanning electron microscopy and X-ray diffraction corroborated the formation of highly crystalline hematite and magnetite nanoparticles with average sizes of ~80 nm and ~50 nm, respectively. Thermogravimetric analysis revealed remarkable results on the thermal stability of the newly synthesized samples. The optical studies confirmed the formation of a single-phase compound with the bandgaps dependent on the size of the nanoparticles. The electrochemical studies that utilized cyclic voltammetry and electrochemical impedance spectroscopy techniques verified these iron oxide nanoparticles as electroactive species which can enhance the charge transfer process with high mobility. The hysteresis curves of the samples revealed the paramagnetic behavior of the samples with high values of coercivity. Thus, these optimized materials can be recommended for use in future optoelectronic devices and can prove to be potential candidates in the advanced research of new optoelectronic materials for improved energy devices.

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Effect of plasma jet on electrochemical properties of silk fibroin hydrogel doped with PEDOT:PSS

Zhou

Cong

et al. 2023

Energy Science & Engineering

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In this study, by injecting cold plasma into the silk fibroin (SF) solution, and adding poly (3,4-ethylenedioxythiophene): polystyrene sulfonic acid (PED-OT:PSS) into the SF solution, the conductive SF-PEDOT:PSS hydrogel modified by plasma was successfully prepared. The changes of the electrochemical parameters and structure of SF-PEDOT:PSS hydrogels after plasma modification were observed with plasma discharge time (60, 120, 180 s) and the type of working gas (Ar, air, He) as variables. The results of electrochemical impedance spectroscopy show that both argon plasma and helium plasma can reduce the impedance of SF-PEDOT:PSS hydrogel in the extremely low-frequency range (10 −2 -10°Hz), and a longer discharge time shrinks the impedance, while the impact of air plasma on the impedance of hydrogel is not obvious. The capacitance results show that both argon and helium plasma can make the capacitance of hydrogel larger, and the longer discharge time leads to the larger capacitance. While air plasma can reduce the capacitance of hydrogel. The results of Fourier infrared absorption spectroscopy and X-ray diffraction spectrum show that the secondary structure of SF is mainly β-fold. The results of Raman show that PEDOT:PSS is successfully incorporated into hydrogel, and there exists random coil conformation of SF in hydrogel. The results of X-ray photoelectron spectroscopy show that the SF-PEDOT:PSS hydrogel mainly contains C, O, and N elements.

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Cyclic voltammetry - A promising approach towards improving photoelectrochemical activity of hematite

Cited by 17 publications

References 40 publications

Improved Photoelectrochemical Performance of Chemically Grown Pristine Hematite Thin Films

Improved Photoelectrochemical Performance of Chemically Grown Pristine Hematite Thin Films

Systematic Investigation of Structural, Morphological, Thermal, Optoelectronic, and Magnetic Properties of High-Purity Hematite/Magnetite Nanoparticles for Optoelectronics

Effect of plasma jet on electrochemical properties of silk fibroin hydrogel doped with PEDOT:PSS

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