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In the present study, Mo-BiVO4-loaded and metal oxide (MO: Ag2Ox, CoOx, and CuOx)-loaded Mo-BiVO4 photocatalysts were synthesized using a wet impregnation method and applied for microbial inactivation (Escherichia coli and Staphylococcus aureus) and orange II dye degradation under visible-light (VL) conditions (λ ≥ 420 nm). The amount of MO cocatalysts loaded onto the surface of the Mo-BiVO4 photocatalysts was effectively controlled by varying their weight percentages (i.e., 1-3 wt %). Among the pure Mo-BiVO4, Ag2Ox-, CoOx-, and CuOx-loaded Mo-BiVO4 photocatalysts used in bacterial E. coli and S. aureus inactivation under VL irradiation, the 2 wt % CuOx-loaded Mo-BiVO4 photocatalyst showed the highest degradation efficiency of E. coli (97%) and S. aureus (99%). Additionally, the maximum orange II dye degradation efficiency (80.2%) was achieved over the CuOx (2 wt %)-loaded Mo-BiVO4 photocatalysts after 5 h of radiation. The bacterial inactivation results also suggested that the CuO x -loaded Mo-BiVO4 nanostructure has significantly improved antimicrobial ability as compared to CuOx/BiVO4. The enhancement of the inactivation performance of CuOx-loaded Mo-BiVO4 can be attributed to the synergistic effect of Mo doping and Cu2+ ions in CuOx, which further acted as an electron trap on the surface of Mo-BiVO4 and promoted fast transfer and separation of the photoelectron (e-)/hole (h+) pairs for growth of reactive oxygen species (ROS). Furthermore, during the bacterial inactivation process, the ROS can disrupt the plasma membrane and destroy metabolic pathways, leading to bacterial cell death. Therefore, we provide a novel idea for visible-light-activated photocatalytic antibacterial approach for future disinfection applications.

Herein, we synthesized in-situ Zr-doped Fe

Herein, we propose the topotactic and self-templated fabrication of Zn1-xCdxSe porous nanobelt-ZnO nanorod (termed as ZnCdSe/ZnO) photoelectrode via the cadmium (Cd2+) ion-exchange process on zinc (Zn) foil. Inorganic-organic hybrid ZnSe(en)0.5 nanobelt (NB) was synthesized on Zn foil by a facial solvothermal method at different temperatures of 140, 160, and 180 °C for 12 h. The interfacial properties and photoelectrochemical (PEC) performance of inorganic-organic ZnSe(en)0.5 NB fabricated through the Cd2+ ion-exchange method at different time durations of 6, 12, 18, and 24 h at 140 °C were investigated. The TEM analysis results indicate that the inorganic-organic ZnSe(en)0.5 NB transformed into ZnCdSe and a self-assembled ZnO formed on the Zn foil. In particular Cd2+ ion temperature (140 °C/18 h), the optimized ZnCdSe/ZnO-(F) photoelectrode shows an excellent photocurrent density of 14 mA·cm-2 at 0 V vs Ag/AgCl with 219 μmol·cm-2 hydrogen gas evolution for 3 h under 1 sun illumination. The higher photocurrent value resulted from the optimum growth of ZnO, the formation of porous ZnCdSe, and the effective electrolyte penetration for electron-hole pair separation. The photoluminescence spectroscopy shows that the photoexcited charged carriers promoted a longer lifetime. Furthermore, we provide a full account of the possible charge-transfer mechanism during PEC hydrogen production.

A strategy involving CoOx catalyst adsorption and acid treatment for modifying the surface properties of Zr-doped hematite nanocoral (NC) photoanodes has been proposed. Acid-treated Zr-Fe2O3 NCs exhibited a reduced electrode/electrolyte interface resistance and improved surface charge-injection efficiency. X-ray photoelectron spectroscopy data confirmed an increased number of hydroxy groups and the formation of Fe2+ sites on the surface of the acid-treated Zr-Fe2O3 NC, suggesting surface amendment. Furthermore, after surface amendment with a 1 mM Co(OAc)2 solution, the CoOx encapsulated acid-treated Zr-Fe2O3 NC photoanode exhibited a photocurrent density of 1.83 mA/cm2 at 1.23 V vs. RHE, following a 200-mV cathodic shift in the photocurrent onset compared with the bare Zr-Fe2O3 NC. The experimental results indicated the efficacy of acid treatment and CoOx adsorption for reducing the surface state and enhancing the photoelectrochemical water-oxidation performance. The acid-treatment step in the CoOx-encapsulated acid-treated Zr-Fe2O3 NC provided a CoOx catalyst adsorption bond and permitted the kinetics of the charge-transfer process. This synergistic strategy of acid treatment and CoOx adsorption for enhancing the PEC performance provides a reference for accelerating the charge separation for other photoelectrodes.

With regard to both the activity and stability of photoelectrode materials, in this study, a hematite cauliflower-like structure with irregularly loaded ZrO2 (ZrO2–Fe2O3 CF) was prepared from as-deposited samples. The effect of post-synthetic treatments such as systematic high-temperature heating at various temperatures (650, 700, 750, and 800 °C) for 10 min, followed by rapid cooling at room temperature (quenching) on interfacial properties and photoelectrochemical performance was investigated in detail. The photoelectrochemical performances of the quenched ZrO2–Fe2O3 CF samples were compared to those of conventionally synthesized hematite nanorod photoanodes quenched from 800 °C (PQ800). Interestingly, ZrO2–Fe2O3 CF photoanodes quenched from 650 °C exhibited 0.62 mA cm−2 photocurrent density at 1.23 V vs. RHE, which was 14 times higher than that of the conventionally synthesized hematite quenched from 650 °C (PQ650). Furthermore, ZrO2–Fe2O3 CF photoanodes quenched from 800 °C revealed a photocurrent density of 1.66 mA cm−2 at 1.23 V vs. RHE (twice that of PQ800) and improved charge separation efficiencies of ηbulk = 15.6% and ηsurface = 94.6%, respectively. The XPS and HRTEM results also confirmed the irregular ZrO2 loading on the surface of Fe2O3 CF. A possible formation and charge transfer mechanism of ZrO2–Fe2O3 CF was proposed based on a series of temperature-dependent experiments.

Herein, in situ zirconium-doped hematite nanocoral (Zr–Fe2O3 (I) NC) photoanode was prepared via a specially designed diluted hydrothermal approach and modified with Al3+ co-doping and electrodeposited cobalt–phosphate (“Co–Pi”) cocatalyst. Firstly, an unintentional in situ Zr–Fe2O3 (I)) NC photoanode was synthesized, which achieved an optimum photocurrent density of 0.27 mA/cm2 at 1.0 V vs. RHE but possessed a more positively shifted onset potential than conventionally prepared hematite nanorod photoelectrodes. An optimized amount of aluminum co-doping suppresses the bulk as well as surface defects, which causes a negative shift in the onset potential from 0.85 V to 0.8 V vs. RHE and enhances the photocurrent density of Zr-Fe2O3(I) NC from 0.27 mA/cm2 to 0.7 mA/cm2 at 1.0 V vs. RHE. The electrodeposited Co–Pi modification further reduce the onset potential of Al co-doped Zr–Fe2O3(I) NC to 0.58 V vs. RHE and yield a maximum photocurrent of 1.1 mA/cm2 at 1.0 V vs. RHE (1.8 mA/cm2 at 1.23 V vs RHE). The improved photocurrent at low onset potential can be attributed to synergistic effect of Al co-doping and Co–Pi surface modification. Further, during photoelectrochemical water-splitting, a 137 and 67 μmol of hydrogen (H2) and oxygen (O2) evolution was achieved over the optimum Co–Pi-modified Al-co-doped Zr–Fe2O3(I) NC photoanode within 6 h. The proposed charge transfer mechanism in optimum Co–Pi-modified Alco-doped Zr–Fe2O3(I) NC photoanodes during the photoelectrochemical water splitting was also studied.

The development of advanced assemblies of interfacial under- and overlayered photoanodes is an effective technique to overcome the problem of slow charge separation and enhance solar energy conversion. The present study reports in situ zirconium-doped zinc ferrite nanocorals (Zr-ZFO NCs) and introduces the concept of diffusion/doping and surface passivation using a TiO2 underlayer via quenching. The high-temperature quenching aids the Zr doping/Ti4+ diffusion in the bulk and, at the same time, the ZrO2/TiO2 composite layers passivate the surface of ZFO NC photoanodes. The optimum TiO2-underlayer-modified Zr-ZFO (TZF) photoanode shows a dramatically improved photocurrent (0.48 mA cm−2) at 1.23 V vs. RHE, which is twice that of the bare Zr-ZFO. Further, the addition of an Al2O3/CoOx cocatalyst further accelerates the surface reaction kinetics of the TZF, and significantly improved charge separation efficiency, photocurrent density (0.73 mA cm−2 at 1.23 V vs. RHE; and 0.97 mA cm−2 at 1.4 V vs. RHE), and stability were obtained. Compared to conventional ZFO nanorods (0.14 mA cm−2 at 1.23 V vs. RHE), the optimized sample shows a 421% increase in photocurrent density. Additionally, the TZF/Al2O3/CoOx_1 mM photoanode generates 65 and 130 μmol oxygen and hydrogen, respectively, under simulated 1 sun illumination. Thus, the “sandwich” strategy for Zr-ZFO with a TiO2 underlayer and spontaneous surface passivation via quenching could be expanded for the design and fabrication of many low-efficiency photocatalysts and the production of cost-effective PEC water splitting photoelectrodes.

ZnFe2O4 nanorods (NR's) were prepared by a chemical conversion method from β-FeOOH NRs grown on FTO substrates. To activate their photoactivity of ZnFe2O4 NRs for solar water splitting, the surface passivation was achieved with SiO2 layer via facile and effective spray pyrolysis method. The presence of SiO2 layer enhances the photocurrent density of the Pristine ZnFe2O4 from 143 µA/cm2 to 212 µA/cm2 at 1.23 VRHE for 0.25 mM Si–ZnFe2O4, representing two time increment in the photocurrent density. The influences of amount of Si precursor (Tetraethyl orthosilicate) solutions on the physical properties and the passivation effect of SiO2/ZnFe2O4 interfaces were investigated. This improved photoresponse of the Si-treated ZnFe2O4 NRs was attributed to the excellent charge transfer electrode/electrolyte interface. The effectively improved charge transfer properties of the Si-treated ZnFe2O4 NRs were demonstrated by the electrochemical impedance spectroscopy (EIS), Mott–Schottky (MS) and intensity-modulated photocurrent spectroscopy (IMPS) analyses.

The objective of this study was to report the preparation of a highly efficient hematite nanorod photoanode by H2 treatment of the β-FeOOH nanorod with subsequent quenching in air at lower temperature activation for photoelectrochemical (PEC) water oxidation. The hematite nanorod photoanode (H650) prepared by thermally treating the β-FeOOH nanorod at 360 °C for 1 h under H2 flow and quenching at 650 °C for 10 min in air exhibited a remarkable photocurrent of 1.17 mA cm−2 at 1.23 V vs. RHE, which was 20 times higher than that of hematite quenched at the same temperature without H2 treatment. Such enhanced PEC performance was attributed to high Sn4+ diffusion from the fluorine doped SnO2 (FTO) substrate via H2 treatment and Sn4+ doping by subsequent lower temperature quenching. Our density functional theory (DFT) calculation supports our experimental results and proposed mechanism in that the Sn replacement reaction of magnetite (Fe3O4, H2-reduced β-FeOOH) occurs at a lower temperature and requires a smaller energy than that of akaganeite (β-FeOOH).

To solve energy crisis, the engineering of highly efficient and cost-effective photoanodes is urgently required for clean fuel generation. Herein, CdSe(en)0.5 (en = ethylenediamine) hybrid photoanodes were synthesized by a solvothermal approach. It was revealed that a second in situ hydrothermal treatment successfully converts cadmium foil-based inorganic-organic CdSe(en)0.5 (en = ethylenediamine) hybrid nanosheets to an oriented cadmium hydroxide crowned CdSe nanowire-decorated porous nanosheet (Cd(OH)2/CdSe NW/NS) heterostructure by dissolution and regrowth mechanisms. The alteration in second hydrothermal reaction conditions could modify the morphology and optical properties of the Cd(OH)2/CdSe NW/NS heterostructure photoanodes. The possible growth mechanism of the Cd(OH)2/CdSe NW/NS porous structure is studied at various second hydrothermal times using the control experiments of the synthesis. The optimized 3D porous Cd(OH)2/CdSe NW/NS photoanodes exhibited an outstanding photocurrent density of 6.1 mA cm-2 at 0 V vs. Ag/AgCl, which is approximately 7.6 times higher than that of the inorganic-organic CdSe(en)0.5 hybrid under light irradiation (>420 nm cut off filter). A mechanism is proposed to explain the enhanced charge separation at the Cd(OH)2/CdSe NW/NS photoanode/electrolyte interface, which is supported by PL and photoelectrochemical analyses. These findings open an avenue of phase and morphology transmutation for efficient formation of other hierarchical structures of metal selenides and sulfides. Additionally, the Al2O3 co-catalyst can act as effective hole trapping sites and improves the stability of the photoelectrode through the timely consumption of photogenerated charges, particularly holes.

The dry sliding wear performance of eutectic Al-7075-CNT-Gr composites was estimated using a pin-on-disc wear test. According to the results, the wear and friction coefficients dropped gradually as the weight % of graphite elements improved. The composite’s wear resistance increased significantly as the sliding speed increased from 1 m/s to 2 m/s at 49 N while the load remained constant. 7075-7.5 wt percent Gr amalgamated, on the other hand, had a more significant coefficient of friction as the sliding speed increased from 1 m/s to 2 m/s at 49 N. After the test, the researchers looked at how the worn-out surfaces of the specimens originated. The mechanically mixed layer of oxides and iron was used as an effective tribolayer to increase the wear resistance at more incredible sliding speeds in the wear test.

The 3D structure assembly of CdSe tetrakaidecahedron (TDH) modified with the oxygenated CdS nanorose (NR) structure plays a crucial role in the photoelectrochemical (PEC) performance because of its...

A highly three-dimensional CdIn2S4 deposited TiO2 (CdIS/TONR/FTO) heterostructured photoanode has been fabricated via a two-step hydrothermal process to enhance the photoelectrochemical (PEC) performance. In this work, bare TiO2 nanorods are grown successfully on the fluorine-doped tin oxide (FTO) substrate via a hydrothermal method (TONR/FTO), and a second-step hydrothermal synthesis is used to grow CdIn2S4 flower nanostructured layer over the top surface of the bare TONR/FTO. Structural, morphological, optical, and elemental analysis of CdIS/TONR/FTO heterostructure photoanode is investigated in detail. PEC performances are studied in 0.2 V versus Ag/AgCl in mixed sulfide-based electrolyte for various concentrations of CdIn2S4 deposited on photoanodes. The photocurrent density for optimized (×4)-CdIS/TONR/FTO heterostructure photoanode is observed to be three times higher than that of the bare TONR/FTO photoanode. This excellent PEC performance is ascribed to the way that the deposited CdIn2S4 layer and TiO2 nanorods synergistically allow the absorption of a wide portion of the solar spectrum under back illumination, and provide efficient separation of the electron-hole pairs in the photoanode architecture. The EIS and IMPS analysis also reveal the significance of CdIn2S4 layer that provides the lowest charge-transfer resistance at the interface and high electron-transfer rate in CdIS/TONR/FTO photoanode. Mainly, the deposited CdIn2S4 layer significantly broadens the optical absorption capacity, and provides efficient electrons-holes transfer that reduces the recombination losses of the charge carriers. The proposed charge transfer mechanism in CdIS/TONR/FTO heterojunction is well studied.

Herein, we report the surface treatment on Zr4+/Al3+ codoped α-Fe2O3 photoanode for high-performance photoelectrochemical water splitting. A high-temperature quenching exhibits the Zr4+/Al3+ codoping in α-Fe2O3 photoanode without damaging morphology. The presence of Zr4+/Al3+ codoping shows a cathodic shift in onset potential, but lack of increment in photocurrent reveals the major role of passivation and the minimum doping effect of aluminum. Additionally, CoOx cocatalyst exhibits increment in photocurrent with the greater cathodic shift in onset potential than the pristine α-Fe2O3 nanorods. The CoOx surface-reworked Zr4+/Al3+ codoped α-Fe2O3 photoanode displays the highest photocurrent of 1.5 mA/cm2 at 1.23 V vs. RHE (76% increment over the pristine α-Fe2O3) and 0.7 mA/cm2 at 1.0 V vs. RHE (102% increment over the pristine α-Fe2O3). The systematic characterization carried out using x-ray diffraction and scanning electron microscopy confirms that after Zr4+/Al3+ codoping, and surface treatment, the crystalline structure, and morphology of the photoanodes remains unchanged. X-ray photoelectron spectroscopy confirmed the existence of Zr4+/Al3+ codopants in the hematite nanostructure. The electrochemical properties of the photoanode suggest that Al3+ and Zr4+ codoping, as well as surface treatment with CoOx, cocatalyst lowers charge transfer resistance across the FTO/hematite interface, and hematite/electrolyte interface. This designs not only lowers onset potential but also offers the blueprint for the development of an efficient catalyst for solar water oxidation.

In this study, we have synthesized hierarchical TiO2@In2O3 heteroarchitecture photoanodes via a hydrothermal method and studied their interfacial charge carrier dynamics through water splitting and organic decomposition. Photoelectrochemical measurements show that the IN-0.4 exhibits an obvious enhancement in photocurrent density compared to the pristine TiO2. Electrochemical impendence spectroscopy (EIS) and Time-resolved photoluminescence (PL) have been employed to study the charge recombination in TiO2@In2O3 nanostructure. The surface passivation of TiO2 nanorods (NRs) with In2O3 nanostructures helps to the suppression of the surface defects. The surface-passivated photoanode (IN-0.4) has demonstrated the improved hydrogen generation activity (125 μmol∙h−1) of TiO2 nanorods (NRs) with In2O3 nanostructures during water splitting and organic decomposition. The probable causes of the enhancement in hydrogen evolution could be due to (i) enhanced photogenerated electron transport (ii) increased active surface area with In2O3 and/or (iii) catalytic activity of In2O3. Moreover, the photoelectrocatalytic activities of IN-0.4 were slight affect during degradation of Bisphenol A and methyl orange dye, which might be due to the lower hole mobility in TiO2@In2O3 heteroarchitecture photoelectrodes. These sightings and proposed schematic model can help to understand the charge transfer dynamics in hierarchical TiO2@In2O3 heteroarchitecture photoelectrodes as well as designing multifaceted photoelectrodes for solar energy conversion.

The surface modified tetravalent ions doped hematite nanorod photoanodes has been synthesized by successive hydrothermal and spin coating approaches. The effect of tetravalent ion (Sn, Ti, and Zr) doping and high temperature annealing on to the morphological, structural and photoelectrochemical properties has been investigated. Photoelectrochemical analyses indicate tetravalent doping (Sn, Ti, and Zr) and high-temperature annealing (800 °C) showed higher photocurrent and improved activity towards Orange-II dye degradation, compared to the pristine hematite film. Amongst tetravalent dopants, Zr4+ doped hematite can significantly enhance the photocurrent density (1.37 mA cm−2 at 1.23 V vs. RHE) as well as the Orange-II dye degradation activity (93% under one sun illumination in 270 min). Kinetic parameters are also investigated by first-order rate equation. Further, Zr–Fe2O3 photoanode modified with the appropriate composition of CoOx and specific structural features demonstrated improvement in photocurrent from 1.6 to 1.78 mA cm−2 (at 1.4 V vs. RHE). The efficient charge carrier separation and generated hydroxyl radicals led to enhancements of the Orange-II dye degradation efficiency up to 97% within 270 min. The significant decrease in chemical oxygen demand values suggests the removal of Orange-II dye. This work demonstrates that enhancement in photoelectrochemical activity is due to the combined effect of passivation of surface states and the formation of CoOx/Zr–Fe2O3 heterojunction.

We introduce a simple strategy to unintentional heterogeneous Ti4+/Sn4+ doping and surface passivation of hematite via TiO2 underlayers at high temperature quenching. The effects of the controlled ...

In this work, the hydrothermal approach has been used to prepare and control the morphology of Bi2S3 nanosheet (NS)/Zr doped Fe2O3 nanorod (NR) heterojunction grown on fluorine doped tin oxide (FTO) phoptoelectrodes. The effect of morphology of Bi2S3 NS was examined by comparing the photocatalytic activity of Zr:Fe2O3 nanorod with synthesized heterojunctions. This novel heterojunction photoanode exhibits the light harvesting, the photoinduced electron–hole separation and yielding a maximum photocurrent density of ∼1.27 mA cm−2 at −0.4 V vs. Ag/AgCl under one sun illumination. Bi2S3 NS on surface of the Zr:Fe2O3 NR will act as the active material which shows the dramatic improvement in photocurrent generation. Further, effect of silver interlayer on the interface properties of Bi2S3 NS/Zr:Fe2O3 NR heterojunction was also studied. The results indicated that the silver interlayer reduces charge recombination at interface of Bi2S3 and Zr:Fe2O3. Also, the surface plasmon resonance of Ag and controlled morphology enhances the performance (1.5 mA cm−2 at −0.4 V) as well as improves the stability of Bi2S3/Zr:Fe2O3 heterojunction photoelectrode. This unique design of the nanoarchitecture provides an attractive pathway for the photogenerated electrons and the silver interlayers has great impact on enhancing charge separation and improving stability of photoanode.

Various solar conversion materials with 1D nanostructure have been developed and are being widely investigated for various solar fuel generation applications. In this study, aligned and non-aligned CdS nanowires (NWs) were synthesized on Cd foil or in solution via solvothermal processes. In the case of aligned CdS NWs, the relative intensity of the (0 0 2) diffraction peak was higher than that of the non-aligned CdS NWs, which indicated that the NWs grew preferentially in the (0 0 1) direction. The systematic comparison between the photoelectrochemical properties of both electrodes revealed that the aligned CdS NW electrode displayed markedly enhanced photocurrent (by a factor of 7), photoelectrochemical hydrogen production (by a factor of 10), and photostability in comparison with those of the non-aligned NWs electrode fabricated on FTO glass. Resistance (Rµ) through the inner part of the aligned CdS NWs was very small due to a low grain-boundary resistance (by a factor of 130). This low resistance induced efficient charge transfer, reducing the charge recombination loss and assisting the charge transport along the axial direction of the aligned NWs. Time-resolved photoluminescence spectroscopy confirmed that the charge separation in the aligned CdS NWs is longer than that in the non-aligned CdS NWs (by a factor of 1.6).

Herein, we propose the topotactic and self-templated fabrication of Zn

To solve energy crisis, the engineering of highly efficient and cost-effective photoanodes is urgently required for clean fuel generation. Herein, CdSe(en)

In present work, we synthesized ZnFe2O4 nanorods on a fluorine-doped tin oxide substrate using spray coating method followed by two-step high-temperature quenching (HTQ). X-ray photoelectron spectroscopy (XPS) results indicate that Sn4+ is diffused from the FTO substrate after the second quenching, which could help in minimizing the recombination of photogenerated carriers. Photoelectrochemical measurements of the ZnFe2O4 nanorod photoelectrodes quenched at 780 °C, 800 °C, and 820 °C indicate that among the studied samples (ZFO1, ZFO2 and ZFO3), the highest photocurrent density was observed for nanotextured ZFO3 photoelectrodes (130 µA cm−2 at 1.23 V vs RHE). The photoelectrochemical performances of the ZnFe2O4 nanorods after the second quenching were compared with those of the firstly quenched ZnFe2O4 nanorod samples; water-oxidation photocurrent density of the former (ZFO3) was increased by 6.9 times compared with that of the first quenching (PZFO). Intensity modulated photocurrent spectroscopy (IMPS) and photoluminescence (PL) results confirm the faster charge extraction was achieved for the ZFO3 photoelectrode. Thus, the overall photocurrent density during the second quenching process results from the effectively improved crystallinity, the reduced strain and suppressed charge–carrier recombination's on both the surface as well as in the bulk of the ZnFe2O4 nanorods. In terms of solar water splitting, these research findings provide an effective route for the synthesis of other nanostructures.

Here, we establish a methodology and phenomena for systematically assessing the photoelectrochemical transformation of the BiVO4 to Bi2S3/BiVO4 hybrid heterostructure during in-situ solar hydrogen ...

This work focuses on dependence of incident light illumination direction on the photoelectrochemical performance of hydrothermally prepared two dimensional ZnIn2S4 nanosheets/one dimensional rutile TiO2 nanorod arrays (2D ZIS NS's/1D R-TNR's) heterostructure photoelectrodes. The 2D ZIS NS's are grown on the 1D R-TNR's/FTO substrates by varying the concentration of ZIS precursor in the hydrothermal method, forming 2D ZIS NS's/1D R-TNR's heterostructure. One dimensional rutile TiO2 nanorod arrays (1D R-TNR's) provide excellent electron transfer pathway and role of the 2D ZIS NS's is to offer effective visible light absorbing surface onto the 1D R-TNR's and extended the absorbance spectrum from ultraviolet to visible region; bathochromic shift occurs. This binary heterostructure provides the lower resistance, shortest electron transport time and less recombination under the back side illumination (BSI) and effectively contributed to charge separation and transport in 2D ZIS NS's/1D R-TNR's heterostructure. However, the results demonstrate that the front side illumination (FSI) results in poor PEC performance; because of blockage of light at the surface of 2D ZIS NS's. Further, these results show that BSI could also be applicable for other heterostructures, where the low band gap sulfide materials need to be engineered on large band gap metal oxide for energy harvesting in future prospect.

The vertically aligned TiO2 nanorod arrays (NRA) with manipulated aspect ratio were hydrothermally synthesized by changing the amount of the titanium (Ti) precursor in the initial growth solution. FE-SEM images show the optimum morphology, density and aspect ratio of the well-aligned TB-1.2 NRs on the surface of the FTO substrate. The UV-vis-absorption measurements revealed that a sample prepared at TB-1.2 can provide an increased light trapping effect. PEC analyses demonstrated that the TiO2 nanorods deposited at TB-1.2 of Titanium butoxide show a relatively high PEC conversion efficiency (3.5 times) compared with the TB-0.8 prepared TiO2 at a 1.0 V versus RHE. The higher PEC performance is believed to be the result of an enhancement of the optimum aspect ratio, light trapping, an efficient charge separation, and the high carrier transport in the vertically aligned TiO2 NRs. Further, the PEC based organic dye degradation experiments showed 77% and 94% removal of Orange II and methylene blue respectively. Additionally, 109 μmol h−1 cm−2 hydrogen generations were attributed using optimized vertically aligned TiO2 NRA’s. Thus, the appropriate morphology manipulated the TiO2 NRAs are useful for solar conversion applications.

In present article, WO3 thin films have been successfully synthesized by chemical spray pyrolysis approach. The effect of spraying quantity of solution onto the photoelectrochemical (PEC), structural, morphological, and optical properties has been studied. Film prepared at 40 ml solution quantity shows the excellent photoelectrochemical performance (Isc= 0.69 mA/cm2 and Voc = 0.64 V) in 0.05 M concentrated H2SO4 electrolyte. X-ray diffraction studies reveal that the synthesized WO3 thin films are polycrystalline with monoclinic crystal structure. The chief vibrational modes of the WO3 sample, located at 712.64 and 804.28 cm−1 corresponding to the stretching and the bending of O W O bond respectively and are consistent with a monoclinic structure. The estimated band gap energy of WO3 thin films varies from 2.37 to 2.45 eV with respect to quantities of spraying solution and it exhibits absorption in visible region. Film shows a maximum specific surface area of 31.63 m2/g. Photoelectrocatalytic degradation of brilliant blue dye in aqueous solutions is studied. The end result shows that the degradation percentage of brilliant blue using WO3 photoelectrode has reached 92% under visible light illumination after 240 min. The enhancement in photoelectrocatalytic activity of optimized 40 ml WO3 sample is mainly due to the suppressed the recombination rate of photogenerated electron–hole pairs. This study provides an effective WO3 photoelectrode for removing of organic pollutants present in the water.

The need to utilize TiO2 based metal oxide hetero nanostructures for the degradation of environmental pollutants like Rhodamine B and reactive red 152 from the wastewater using stratified WO3/TiO2 catalyst under sunlight illumination. WO3, TiO2 and stratified WO3/TiO2 catalysts were prepared by a spray pyrolysis method. It was found that the stratified WO3/TiO2 heterostructure has high crystallinity, no mixed phase formation occurs, strong optical absorption in the visible region of the solar spectrum, and large surface area. The photocatalytic activity was tested for degradation of Rhodamine B (Rh B) and reactive red 152 in an aqueous medium. TiO2 layer in stratified WO3/TiO2 catalyst helps to extend its absorption spectrum in the solar light region. Rh B and Reactive red 152is eliminated up to 98 and 94% within the 30 and 40 min respectively at optimum experimental condition by stratified WO3/TiO2. Moreover, stratified WO3/TiO2 photoelectrode has good stability and reusability than individual TiO2 and WO3 thin film in the degradation of Rh B and reactive red 152. The photoelectrocatalytic experimental results indicate that stratified WO3/TiO2 photoelectrode is a promising material for dye removal.

This data article presents the experimental evidences of the effect of TiO2-fluorine doped tin oxide interface annealing and Ni(OH)2 cocatalysts on the photoelectrochemical, structural, morphological and optical properties of Ni(OH)2/CdS/ZnIn2S4/TiO2 heterojunction. The Raman spectroscopy exhibits the sharp features of the rutile phase of TiO2 and in agreement with the X-ray diffraction data. The band gap energy of the 500 °C sample was found to be 3.12 eV, further it was increased to 3.20, 3.22 eV for samples annealed at 600 and 700 °C respectively. The decrease in the band gap energy at 500 °C related to the oxygen vacancies and was analysed by photoluminescence spectroscopy analysis. The synthesis, characterization methods and other experimental details of TiO2 based heterostructure are also provided. The presence of CdS and ZnIn2S4 coating on surface of TiO2 electrodes providing a high surface area, extended visible absorption and helps to improve the change separation. This data article contains data related to the research article entitled “Highly efficient and stable 3D Ni(OH)2/CdS/ZnIn2S4/TiO2 heterojunction under solar light: Effect of an improved TiO2/FTO interface and cocatalyst” (Mahadik et al., 2017) [1]. Keywords: Annealed TiO2 nanorods, CdS/ZnIn2S4/TiO2 heterostructure, Ni(OH)2 cocatalyst, TiO2-FTO interface

In this work, we prepared visible-light active and rhodium and antimony codoped rutile TiO2 nanorods (Rh–Sb:TiO2 NR) for the degradation of organic pollutants and inactivation of microbial pathogens. The Rh–Sb:TiO2 NR sample showed a shift in the absorption band in the visible light region (650 nm). Initially, photocatalytic activity of the Rh–Sb:TiO2 NR was hindered due to its poor surface properties. To improve the surface quality of the less active Rh–Sb:TiO2 NR photocatalyst, the effect of the acid treatment and CuxO impregnation on the Rh–Sb:TiO2 NR were evaluated (CuxO/A–Rh-Sb:TiO2 NR). The photocatalytic activity of the CuxO/A–Rh-Sb:TiO2 NR photocatalyst was remarkably higher than that of the as-prepared sample. The improved photocatalytic activity of less active Rh–Sb:TiO2 NR is due to the synergistic effect of acid treatment and finely dispersed CuxO nanoparticles which improve the charge transfer near the interface of the A–Rh-Sb:TiO2 NR photocatalyst toward CuxO nanoparticles. Deconvolution of ...

In this study, we present an advanced strategy of low-temperature hydrogen annealing combined with high- temperature quenching in air for activating α-Fe2O3 nanorod photoanodes to boost the photoelectrochemical performance. We report that various low-temperature annealing conditions (340, 360, 380, and 400 °C) under hydrogen gas flow convert β-FeOOH into magnetite (Fe3O4) as well as introduce Sn4+ diffusion from FTO substrates to its surface. Furthermore, high-temperature quenching (800 °C) resulted in the phase change of magnetite (Fe3O4) into hematite (α-Fe2O3) and self Sn4+ doping into the hematite lattice. Thus, the hydrogen-assisted thermally activated hematite photoanode achieved a photocurrent density of 1.35 mA cm-2 at 1.23 V vs. RHE and 1.91 mA cm-2 at 1.4 V vs. RHE, which is 70% and 80% higher than that of directly quenched hematite at 800 °C. These combined two step strategies provide new insight into high Sn-self doping for α-Fe2O3 photoanodes and allow for further development of more efficient solar water oxidation systems.