Harnessing solar energy for clean and sustainable fuel production by photoelectrochemical water oxidation over different timescales has been extensively investigated. However, the light-driven photoelectrochemical water oxidation reaction for artificial photosynthesis suffers from poor photon-to-current efficiency. Herein, we demonstrate an experimental analysis of electrolytic pH on photoelectrochemical syngas production by varying the pH of the KOH and NaOH electrolytes using the N-ZnO photoelectrode and analyzing all variables. A maximum photocurrent of 13.80 mA cm-2 at 1.23 V vs. RHE with a 43.51% photon-to-current conversion efficiency was obtained at pH 13 in the aqueous NaOH electrolyte.

Solar-light-driven photoelectrochemical that can utilise water for high-performance artificial photosynthesis for low-cost green hydrogen fuel production. However, the interaction of photoanode with water is crucial to its heterogeneous water oxidation for sustainable fuel production for the replacement of fossil fuels. Here, we report experiment investigations of photoelectrode with temperature for solar energy conversion. These measurements revealed that a rise in temperature affects the catalytic generation of hydrogen in three routes, viz., minimising the required energy for water splitting, reducing bandgap energy and mitigating the resistance at the interface.

n/n/n triple heterojunction photoanodes made up of Zr:W-BiVO4, Fe2O3, and ZnFe2O4 metal oxides are fabricated through a simplistic spray pyrolysis method. Use of Zr and W as dopants in BiVO4 plays an important role as Zr increases the carrier density and W reduces the charge recombination. Further, Fe2O3 and ZnFe2O4 serve as a protective layer for Zr:W-BiVO4, which augmented the photoelectrochemical performance and achieved a 1.90% conversion efficiency in the triple heterojunction. XRD measurements display the crystalline nature and reduction in particle size due to strain in the sample, UV-vis absorbance shows an extended absorption towards the visible region and the FE-SEM imaging confirms the successful deposition of ZnFe2O4 over BiVO4/Fe2O3. By analyzing the band edge position, it was observed that on formation, the triple heterojunction not only suppresses the charge carrier recombination but also utilizes the band edge offset for the water splitting reaction using solar energy.

Abstract This report brings out the role of Au plasmons as the subjacent layer below TiO2 in PEC water splitting for hydrogen generation. Au was deposited on an ITO sheet using DC sputtering with 5 nm and 20 nm thickness and annealed at 300oC for 20 minutes in the N2 atmosphere. TiO2 in the form of the thin film was coated on the already deposited Au layer using a sol-gel spin coating method. Thin films were characterized using tools such as X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and optical absorption spectroscopy. The presence of Au as the subjacent layer in TiO2 shows enhanced absorption (visible region) due to the plasmonic properties displayed by Au nanoparticles. TiO2 with subjacent Au layer (5 nm thickness) was found to exhibit eight times higher photoresponse than the pristine sample at 1.0 V/SCE which can be ascribed to the plasmonic effect of gold nanoparticles extending absorption in the visible region of sunlight.

The present study is focused on nanostructured thin films of nitrogen-doped titanium dioxide (N-TiO2) deposited on ITO glass substrate using the sol-gel spin coating method. The influence of varying ionic strength of elec-trolytes on the photoelectrochemical response was investigated in the mixture of electrolytes (NaOH + Na2SO4 and KOH + K2SO4). The concentration of electrolytes varied from 0.1 M to 3.1 M. The photocurrent-voltage (J-V) characteristic of N-TiO2 electrodes was studied and analyzed for all variables. A maximum photocurrent of 13.25 mA at 1.23 V/RHE was obtained at an ionic strength of 0.7 M in a mixture of NaOH and Na2SO4 electrolytes.

Titanium dioxide (TiO2) has been extensively studied for solar-light-driven water oxidation as photoanode in photoelectrochemical (PEC), but enabled to hold promise for low cost and sustainable fuel. However, the performance of TiO2 for scalable artificial photosynthesis has remained critical obstacle for practical application. Herein, we report the influence of aqueous solution of NaPi and KPi buffer and varying pH from 9.0 to 11.5, with Partially Crystalline Nitrogen-doped Titanium Dioxide (PCNDTO) for solar-derived PEC syngas production and analyzed for all variables. A maximum photocurrent of 4.35 mAcm−2 at 1.23 V/RHE with 9.7–10.9 ml h−1 cm−1 hydrogen production rate was obtained at pH 10.5 in NaPi buffer.

Significant advancement in photoelectrochemical water splitting current is observed using uniquely evolved n/n junction bilayered nano-hetero-structured thin films, WO3/Yb-Mo-BiVO4, as photoanode. Films, synthesized over F:SnO2 glass substrates were characterized by UV–Visible spectroscopy, X-ray diffractometry, atomic force microscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. Using thin films (2% Mo and 4% Yb incorporation) as working electrode in PEC cell, in conjunction with platinum counter electrode, saturated calomel reference electrode, aqueous solution (200 cm3) of K2HPO4 (1.0 M, pH 8.7, temperature 31 ± 3.6 ℃) and 150 W Xenon Arc lamp for illumination, ~ 227–950% increase in Iph is recorded against monolayered pristine films of WO3 and BiVO4. Marked rise in photoelectrochemical cell photocurrent is attributable to expanded absorption of light, coupled with internal electric field in Yb–Mo-incorporated n/n hetero-junction films, reduced electrical resistivity and optimally raised surface roughness that favoured the separation and transfer of photogenerated charge carriers across electrode/electrolyte interface.

Growing energy consumption with the augmentation in universal population to more than nine billion by 2050 and exhausting fossil fuel reserves necessitates a harsh revolution from non-renewable energy reservoirs to renewable energy reservoirs with zero carbon emission. In the present scenario, solar energy prompted photoelectrochemical (PEC) water splitting or "Artificial Photosynthesis" via light gripping semiconductor material, originates out as the most promising methodology in accomplishing the global energy crisis. Recent studies have amply demonstrated the potential of metal-organic frameworks (MOF) to-wards PEC applications. They are porous crystalline coordination polymers assembled through an appropriate choice of metal ions and multidentate organic ligands. Owing to their structural regularity and synthetic tunability, MOFs integration with PEC is consid-ered in terms of enhancing and broadening light absorption, providing active sites and directing charge transfer dynamics. Here, we have explored MOFs role in PEC and classified them into different categories such as photosensitizers, co-catalysts, counter electrode, template and also for imparting additional stability to the electrode system. MOFs medi-ated PEC water splitting is promising but is still rare and in its infancy. Therefore, it is pertinent and timely to take stock of the advancements made and develop insight on the use of MOFs, as an emerging solution for the problems encountered in PEC. This review covers the basics of MOF & mainly describes various case studies done during last 10 years and providing adequate impetus to researchers for critically assessing the recent advances and challenges that are faced by scientists and researchers at large. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

This report brings out the role of Au plasmons as the subjacent layer below TiO2 in PEC water splitting for hydrogen generation. Au was deposited on an ITO sheet using DC sputtering with 5 nm and 20 nm thickness and annealed at 300 °C for 20 min in the N2 atmosphere. TiO2 in the form of the thin film was coated on the already deposited Au layer using a sol–gel spin coating method. Thin films were characterized using tools such as X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and optical absorption spectroscopy. The presence of Au as the subjacent layer in TiO2 shows enhanced absorption (visible region) due to the plasmonic properties displayed by Au nanoparticles. TiO2 with subjacent Au layer (5 nm thickness) was found to exhibit eight times higher photoresponse than the pristine sample at 1.0 V/SCE which can be ascribed to the plasmonic effect of gold nanoparticles extending absorption in the visible region of sunlight.

We present here a combined study on the photoelectrochemical activity of highly active Nitrogen doped titanium dioxide thin-film using experiments and First principle density (DFT) based calculation. Hybridization of N 2p with O 2p and localized valence band upshifting leads to the reduction in band-gap of N-TiO2. To validate theoretical findings, the role of nitrogen in TiO2 is revisited with a focus on partial crystallinity. The best-case photoelectrode, nanostructured partially crystalline nitrogen-doped titanium dioxide (PCNDTO) offered photocurrent density of 24.3 mA/cm(2) at 1 V versus saturated calomel electrode (SCE). The absence of well-defined peaks and long-range order in XRD pattern and Raman spectrum respectively suggests partially crystallinity. High-resolution transmission electron microscopy (HR-TEM) images confirm the presence of TiO2 crystals in the amorphous matrix. High photoelectrochemical response can be attributed to the abundance of hydroxyl groups, high electrochemical active surface area, reduced charge transfer resistance, and reduced charge carrier recombination rate. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

We report here the fabrication of sputter-deposited Au nanoparticles on ITO (Sn-doped indium oxide)-coated glass substrate. The effect of varying annealing parameters, viz., time and temperature in conjunction with varying thickness parameters has been thoroughly investigated. Synthesized Au nanoparticles were characterized using a field emission scanning electron microscope (FE-SEM), Rutherford backscattering (RBS) measurement, X-ray diffraction (XRD), and optical absorbance spectroscopy. The role of annealing temperature and time duration on the evolution of Au nanoparticles has been discussed in detail based on optical absorbance spectroscopy. The present study shows that 5 nm thickness Au thin film which was annealed at 500 °C for 90 min exhibited the strongest surface plasmon resonance (SPR) effect.

Photoelectrochemical hydrogen generation has been investigated using Yb co-doped (at varied concentration) and 2% Mo doped BiVO4 thin films. Prepared thin films were used as photoanode for photoassisted PEC water splitting. Doping of Mo6+ and Yb3+ led to extended absorption of light with marginal fall in band gap energy. Significantly high PEC photocurrent (-1.12 mA cm-2 at 1.9 V vs. RHE) is recorded under 1 sun illumination in K2HPO4 electrolyte. The effect is largely attributable to better charge transfer and reduced recombination. (c) 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the Web International Conference on Accelerating Innovations in Material Science - 2020.

Multiwall carbon nanotubes (MWCNTs) modified n- type Ni:Bismuth Vanadate photoanode has been prepared and investigated for solar energy induced water splitting for hydrogen generation. 0.5 wt% MWCNTs modified Ni:BiVO4 (M3) sample displayed the best response in comparison to the other samples. Electrochemical impedance spectroscopy (EIS) analysis indicates reduced charge transfer resistance and enhanced photoresponse at electrode/electrolyte interface. The calculated flat band potential, photocurrent density and applied bias photon to current conversion efficiency also support the augmentation in photoresponse. Thus, characteristics of MWCNTs has been demonstrated clearly which would support PEC efficiency as well as separation of charge carriers. (c) 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the Web International Conference on Accelerating Innovations in Material Science - 2020.

World power consumption has reached 15 terawatts (TW) and it is all set to amplify in the future. To reduce the energy crisis renewable energy can play a significant role. Solar energy induced hydrogen production via photoelectrochemical path is the most encouraging pathway to find alternate source of energy [1-3]. The present study is focused on nanostructured thin films of zinc oxide (ZnO) deposited on ITO glass substrate using sol-gel spin coating method. Samples were characterized using X-ray diffractometry (XRD), Field Emission Scanning electron microscopy (SEM) and UV-Vis spectrometry etc. The pH of aqueous solution of NaOH & KOH electrolyte was varied from 9-13 pH and its influence was studied on the performance of photoelectrochemical (PEC) water splitting for hydrogen production. The photocurrent-voltage (J-V) characteristic of ZnO electrodes were studied & analyzed for all variables. Maximum photocurrent of 13.8 mAcm-2 at 1.23V/RHE was obtained at pH 13 of NaOH electrolyte. Detailed results would be discussed

Photoelectrochemical response of pristine bismuth vanadate (BiVO4) is limited due to the quick electronhole pair recombination and slower water oxidation. Co-doping of BiVO4 has been investigated to enhance electron-hole pair separation as well as to improve photoelectrochemical performance. Present study, therefore, is focused on understanding the synergistic effect of zirconium (Zr) and tungsten (W) on the photoelectrochemical performance of bismuth vanadate. Series of samples with varying concentrations of W and fixed concentration of Zr are prepared. Compared to the pristine sample, sample with 4% W+3.5% Zr-BiVO4 exhibited (a) enhanced photocurrent density, (b) more roughness (18.01 nm), (c) more negative flat band potential (-0.28 V), (d) high donor density (4.0 x 1020 cm-3) and (e) least radius in nyquist plot. The depletion width and Debye length is found to be minimum for the same sample which confirms better separation of electron-hole pairs. Further, the enhancement in photoelectrochemical response can be attributed to the synergistic effect of Zr and W co-doping which augments the photon harvesting rate and separation of electron-hole pairs.

Metal halide perovskites have triggered a quantum leap in the photovoltaic technology marked by a humongous improvement in the device performance in a matter of just a few years. Despite their promising optoelectronic properties, their use in the photovoltaic sector remains restricted due to their inherent instability towards moisture. Here, we report a simple, cost-effective and highly efficient protection strategy that enables their use as photoelectrodes for photoelectrochemical hydrogen production while being immersed in water. A uniform coating of candle soot and silica is developed as an efficient hydrophobic coating that protects the perovskite from water while allowing the photogenerated electrons to reach the counter electrode. We achieve remarkable stability with photocurrent density above 1.5 mA cm −2 at 1 V versus saturated calomel electrode (SCE) for ~1 h under constant illumination. These results indicate an efficient route for the development of stable perovskite photoelectrodes for solar water splitting.

Significant gains in PEC water splitting photocurrent were recorded using n/n junction bi-layered nanohetero-structured (BNHS) thin films, ZnO/Ag-(alpha)Fe2O3, as photoanode. Films, synthesized over ITO (In:SnO2) glass plates, were characterized by X-ray diffractometry, field emission-scanning electron microscopy, atomic force microscopy, UV-visible spectroscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. PEC cell, fabricated through electrical contacting of BNHS films (3% Ag incorporation)/electrolyte (0.1 M NaOH, pH 13, temperature 32 +/- 3.6 degrees C) junction working electrode with platinum counter electrode and saturated calomel reference electrode, yielded nearly 2 and 20 fold increment in photocurrent, against monolayered pristine ZnO and (alpha)Fe2O3 thin films, respectively. Marked gain in PEC cell-response towards water splitting was attributed to high active surface area and n/n hetero-junction that favored the separation and transfer of photogenerated charge carriers. (C) 2020 Elsevier Ltd. All rights reserved.

The present study attempts quantitative determination of changes in the morphological surface features viz. fractal dimension, lower and upper cut off length scale through Power Spectral Density analysis prior to and after irradiation of 100 KeV Ar+ ion beam at incidence angles of 0 degrees, 40 degrees and 60 degrees on ZnO thin films. All the unirradiated and irradiated samples are subjected to photoelectrochemical characterization and a correlation between photo electrochemical performance and morphological parameters is established. Sample irradiated at 40 degrees angle at the fluence of 5 x 10(16) ions/cm(2) is found to possess maximum fractal dimension of 2.72, lower and upper cut off length scale of 3.16 nm and 63.00 nm respectively. This sample exhibits maximum photocurrent density of 3.19 mA/cm(2) and applied bias photon-to-current efficiency of 1.12% at 1.23 V/RHE. Hydrogen gas collected for duration of 1 h for the same sample was -4.83 mLcm(-2). (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

High efficiency photoelectrochemical water splitting is achieved, using uniquely evolved bi-layered nano-hetero-structured (BNHS) thin films, CuO/Cu–ZnO, grown over ITO (In:SnO2) glass substrate by spray-pyrolysis and sol–gel spin-coating. Films were characterized by X-ray diffractometry, scanning electron microscopy, atomic force microscopy, UV–visible spectrometry, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. Significant gain in photocurrent and applied bias photon-to-current efficiency, with 3% Cu incorporated BNHS films yielding maximum photocurrent ~ 2.98 mA cm−2, is attributable to favourable changes in material microstructure and electrical properties. CuO nanparticles existing as dispersed phase in ZnO overlayer and tendering a possible mechanism for the transfer of photogenerated holes from the underneath CuO layer to electrolyte is a highlighting proposition of this report.