Oxygen Gas Production Research Articles

Solar Light-Induced Photoelectrochemical H2 Generation Over Hierarchical TiO2 Nanotube Arrays Decorated with CdS Nanoparticles

The process of converting solar energy into chemical energy through photoelectrochemical (PEC) water splitting holds significant promise for hydrogen and oxygen gas production. In the current study, we have demonstrated the feasibility of designing a high-performance heterojunction photoanode in a scalable manner. This photoanode sensitizes visible light active CdS onto hierarchical TiO2 nanotubes (TNT), thereby enhancing H2 generation. To achieve this, we initially employed an electrochemical anodization technique to fabricate vertically aligned self-organized TNT on a titanium (Ti) substrate. Subsequently, we designed a hierarchical structure for TNT by uniformly decorating them with TiO2 nanoparticles (NPs), thus amplifying the available surface area. By employing the sequential ionic layer adsorption and reaction (SILAR) technique, we establish visible light sensitization. The resulting decorated hierarchical TNT photoanode demonstrates an enhanced photocurrent of 2.60 mA cm−2 under AM 1.5 G simulated solar light, surpassing the performance of hierarchical TNT, and most importantly classic CdS/TNT structures by 17-fold, and 1.6-fold, respectively. Moreover, the developed photoanodes achieved photoconversion efficiency with an applied bias (ABPE) of 2.48%. Thus, this work shows that a hierarchical scaffold can be exploited to achieve enhanced activity in photoelectrochemical H2 generation.

Electrocatalytic Water Oxidation by Mononuclear Copper Complexes of Bis-amide Ligands with N4 Donor: Experimental and Theoretical Investigation.

The present work describes electrocatalytic water oxidation of three monomeric copper complexes [CuII(L1)] (1), [CuII(L2)(H2O)] (2), and [CuII(L3)] (3) with bis-amide tetradentate ligands: L1 = N,N'-(1,2-phenylene)dipicolinamide, L2 = N,N'-(4,5-dimethyl-1,2-phenylene)bis(pyrazine-2-carboxamide), L3 = N,N'-(1,2-phenylene)bis(pyrazine-2-carboxamide), for the production of molecular oxygen by the oxidation of water at pH 13.0. Ligands and all complexes have been synthesized and characterized by single crystal XRD, analytical, and spectroscopic techniques. X-ray crystallographic data show that the ligand coordinates to copper in a dianionic fashion through deprotonation of two -NH protons. Cyclic voltammetry study shows a reversible copper-centered redox couple with one ligand-based oxidation event. The electrocatalytic water oxidation occurs at an onset potential of 1.16 (overpotential, η ≈ 697 mV), 1.2 (η ≈ 737 mV), and 1.23 V (η ≈ 767 mV) for 1, 2, and 3 respectively. A systematic variation of the ligand scaffold has been found to display a profound effect on the rate of electrocatalytic oxygen evolution. The results of the theoretical (density functional theory) studies show the stepwise ligand-centered oxidation process and the formation of the O-O bond during water oxidation passes through the water nucleophilic attack for all the copper complexes. At pH = 13, the turnover frequencies have been experimentally obtained as 88, 1462, and 10 s-1 (peak current measurements) for complexes 1, 2, and 3, respectively. Production of oxygen gas during controlled potential electrolysis was detected by gas chromatography.

Construction of flower-like nanoassembly P-doped MOF-derived MoS2/Co9S8 grown on hexagonal microporous alumino-silicate framework for overall water splitting in alkaline media

Water splitting is a noteworthy process in the field of hydrogen and oxygen gas production. MoS2 has emerged as an effective material for catalyzing water splitting; however, its low electronic conductivity and oxidative corrosion in environmental conditions suppress its practical applications in electrolyzers. Herein, we constructed a new hetero-nanostructure composed of MoS2 and Co9S8 phases, which is assembled onto the hexagonal microporous alumino-silicate (HMS) structure. Different combinations ratios of Mo and Co elements in hetero-nanostructures offered tremendous opportunities for morphology control and, further, modification of chemical and physical properties to enhance the overall water splitting process. HMS/MoS2/Co9S8-31 (with the mole ratio of 3:1 for Mo:Co) showed synergistically enhanced electrocatalytic performance for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) with overpotentials of −127 and 280 mV at 10 mA cm−2, respectively. In the next step, phosphorization of HMS/MoS2/Co9S8-31 was performed via a simple one-step route (HMS/MoS2/Co9S8/P-31), so the overpotentials were reduced to −85 and 200 mV, which shows dramatic improvement in the overall water splitting performance of electrocatalyst. In addition, for a symmetrical electrolyzer, a current density of 10 mA cm−2 was obtained at a quite low cell voltage of 1.56 V. Systematic studies on HMS/MoS2/Co9S8/P-31 and a set of finely designed control catalysts suggest that the enhanced electrocatalytic behavior should be related to electronic coupling effect and modulation between MoS2 and Co9S8 and the advantage of the ordered HMS architecture. In addition, phosphorus doping can modify the electronic properties of hetero-nanostructure and facilitates electron transfer between MoS2 and Co9S8 hetero-phases.

Literature Review on Solar Energy and Biogas Utilisation for the Development of Scalable Co-Generation Power Plants

In this paper, we present the research results related to the project "Development and implementation of a scalable co-generation power plant solution integrating solar energy and biomass utilisation". Our objective is to develop an integrated solution in the field of local renewable and sustainable energy production, storage and use, where solar energy collected by PV/T collector, hydrogen and oxygen gas production by water decomposition, and biogas production by biomass utilisation are integrated into an innovative process, in different scales (scalable), to produce a compact device, which stores solar energy in the form of combustible gas in a container. Our research team members are working on different areas of tasks to achieve this goal. This article reviews the results of the first phase of this work, which involved a literature review and a groundwork.

β-Arsenene Monolayer: A Promising Electrocatalyst for Anodic Chlorine Evolution Reaction

Materials innovation plays an essential role to address the increasing demands of gaseous chlorine from anodic chlorine evolution reaction (CER) in chlor-alkali electrolysis. In this study, two-dimensional (2D) semiconducting group-VA monolayers were theoretically screened for the electrochemical CER by means of the density functional theory (DFT) method. Our results reveal the monolayered β-arsenene has the ultralow thermodynamic overpotential of 0.068 V for CER, which is close to that of the commercial Ru/Ir-based dimensionally stable anode (DSA) of 0.08 V @ 10 mA cm−2 and 0.13 V from experiments and theory, respectively. The change of CER pathways via Cl* intermediate on 2D β-arsenene also efficiently suppresses the parasitical oxygen gas production because of a high theoretical oxygen evolution reaction (OER) overpotential of 1.95 V. Our findings may therefore expand the scope of the electrocatalysts design for CER by using emerging 2D materials.

Efficient Mn‐Ni‐Co nanocomposite–based electrocatalyst for oxygen evolution reaction in alkaline media

AbstractDue to the frequent use of fossil fuels and their direct impact on the environment, new ways of production of energy sources are essentially needed for the current era. Hydrogen is the perfect candidate for renewable energy; however, efficient O2 gas production is associated with a lack of active electrocatalysts that could be low cost effective and comparable to the performance of noble metal RuO2. The newly developed composite has a Tafel slope of 65 mV dec−1 for oxygen evolution reaction (OER) for the nonprecious Mn‐Ni‐Co‐based electrocatalyst. This mixed oxide alloy possesses excellent oxygen evolution activity in alkaline media with the composite material. It is best of fit to produce OER in 1 M KOH media at 1.41 V onset potential, 230 mV overpotential, and the catalyst is highly durable for 40 hr. The electrochemical impedance spectroscopy study strongly provides the fast OER kinetics of 86.5 Ω charge transfer resistance. An active catalyst is needed for the cheaper generation oxygen gas production on large scale. Thus, outperform, stable, and inexpensive catalysts are highly demanded O2 gas production from the electrolysis of water through oxygen evolution. Herein, we present an efficient and highly stable catalyst based on transition metal oxide ternary Mo‐Ni‐Co nanostructures and their composite for water splitting in basic conditions for the first time. The presented catalysts are up to the mark of ruthenium oxide performance and superior to several transition metal dichalcogenides. This fabrication technology is a new roadmap for the development of active and scalable oxygen‐evolving catalysts by overcoming the issues of fewer catalytic edges, low density, and poor conductivity. The obtained results demonstrate highly favorable on the Mn‐Ni‐Co for OER due to 173.20 Ω small charge transfer resistance values and 1.97 mF capacitance values.

Promoting highly dispersed Co3O4 nanoparticles onto polyethyne unraveling the catalytic mechanism with stable catalytic activity for oxygen evolution reaction: From fundamentals to applications

The solution to overcome the energy crisis in the globe with saving the environment from pollution and the community health, along with other applications of electrochemical for water splitting to get hydrogen and oxygen as a clean fuel. Likewise, the conducting polymers experience as stability over long time, or some time the breaking of conducting polymer chain is unavoidable with addition of polymer. For many reasons, we use noble metal co-catalysts in conjunction with semiconductors for improved hydrogen and oxygen gas production by the water splitting. The morphological characterization, & chemical composition of pristine & composite material studies with the help of different analytical techniques as like SEM, EDX, XRD, XPS & HRTEM. An outperform and active non-noble electrocatalyst for the oxygen evolution reaction which is a hotspot in the current research activities for oxygen & hydrogen production with zero carbon dioxide emission. Herein, we present an advanced material Co3O4/polyethyne for the first time to produce oxygen at a reasonable overpotential. The best oxygen evolution performance of Co3O4/polyethyne (20) providing the best performance at low overpotential 260 mV at 10 mAcm−2 the Tafel slope 64 mVdec−1, further strongly acceptable durability approximately for the 30 h & finally obtained charge transfer resistance value of 82.58 Ohms & greater capacitance 1.56 mF value for Co3O4. The key element in the success of newly developed catalyst is the greater amount of Co3O4 nanoparticles due to selective growth on polyethyne which has played a dominant role in oxygen production. It is because of the worth mentioning properties of polyethyne as a good electrical conductor, as efficient catalyst Co3O4 with more surface roughness and high surface area, which is strongly boosting the production of oxygen. The developed material can be applied in other competing fields such as lithium-ion batteries, solar cells, energy storage devices, and photochemical water splitting.

Determining design criteria to reduce power and cost in filling high-pressure oxygen cylinders directly from cryogenic air separation plants

Cryogenic air separation plants produce pressurized oxygen gas at 150 bar and 99.8% purity to fill oxygen cylinders directly. It is either produced by compression in oxygen compressor (external compression) or pumping and vaporizing liquid oxygen in main heat exchanger by incoming air (internal compression). Small and medium-scale plants differ in the types of main heat exchanger, compression and expansion devices owing to limitations of market availability. Levelized cost of production of oxygen gas is about 9% less in external compression, though internal compression process is far more fire-safe. Design and operating parameters applicable for internal compression plants supplying oxygen at 40 bar cannot be extended to 150 bar plants due to the differences of fluid properties between super-critical and sub-critical oxygen. UA (surface area times overall heat transfer coefficient) of main heat exchangers, flow and pressure of incoming air are optimized for minimum capital and operating costs. If the chosen flow and pressures deviate substantially from the optimum points, size of main heat exchanger may even increase five-fold. Ideally, 27–29% of total air intake should be compressed between 110 and 100 bar in a medium-scale internal compression plant to keep levelized cost of production at the minimum.

Exergy and economic analyses of a novel hybrid structure for simultaneous production of liquid hydrogen and carbon dioxide using photovoltaic and electrolyzer systems

Power-to-X technology that converts renewable electricity to chemicals and liquid fuels will be a key component of the energy turnaround. However, for a successful transition toward fossil-free energy alternatives, serious issues associated with renewable energy storage have to be addressed. Here, we report an innovative power-to-liquid hydrogen and carbon dioxide plant. The proposed integrated plant is composed of five subsystems: power generation using grid-connected solar photovoltaic (PV) subsystem, hydrogen and oxygen gas production using an electrolyzer, oxyfuel power plant for power and heat generation, carbon dioxide liquefaction using an absorption–compression refrigeration subsystem, and a hydrogen liquefaction subsystem. This hybrid structure produces 3.359 kg/s (∼300 ton/day) liquid hydrogen and 10.04 kg/s liquid carbon dioxide. The total exergy efficiency and specific energy consumption of the hydrogen liquefaction system are 94.87% and 3.368 kWh/kgLH2, respectively. Exergy analysis of this integrated structure shows that the largest contribution of exergy destruction (30.58%) is associated with the photovoltaic system and the lowest exergy efficiency (25.28%) belongs to the Turbine in an oxy-fuel subsystem where it, interestingly produces over 70% of the total energy consumption of the plant. Furthermore, the economic analysis of the plant indicates that the time required for the return of capital is 4.794 years, where the prime price of the product and the value added are 0.1921 US$/kgLH2 and 0.5433 US$/kgLH2, respectively. This work can certainly provide a new approach to producing liquid hydrogen and carbon dioxide for long-distance transportation and CO2 reduction using solar as the renewable energy source.

Replacement of feed by fresh microalgae as a novel technology to alleviate water deterioration in aquaculture.

The main aim of this work was to evaluate the feasibility of microalgae-assisted aquaculture and explore the relevant mechanisms. In this regard, our work explored the pollution problems in traditional aquaculture and studied the contribution of microalgae to eutrophication control, oxygen gas production and feed replacement. Besides, potential protection mechanisms of microalgae-assisted aquaculture were studied by bacterial community profile analysis and microscope observation. The results showed that microalgae performed well in nutrient assimilation and oxygen production, thus slowing down the eutrophication and preventing oxygen depletion in aquaculture. Study of the mechanisms revealed that microalgae-assisted aquaculture contained much fewer pathogens and a microalgal biofilm was formed to prevent the eutrophication caused by sludge degradation. It is expected that the findings in this work can support the further development of microalgae-assisted aquaculture and promote the industry upgrade.

Investigation of PPIX-Lipo-MnO2 to enhance photodynamic therapy by improving tumor hypoxia.

The efficacy of photodynamic therapy (PDT) is reduced in the context of hypoxic environments. This is problematic, considering that hypoxia is exhibited in the vast majority of malignant tumors. Thus, increasing the concentration of oxygen in malignant tumors improves PDT treatment outcomes. Studies show that MnO2 nanoparticles can produce oxygen when it reacts with endogenous H2O2. Herein, we encapsulated Protoporphyrin IX (PPIX) in the liposome bilayer (PPIX-Lipo), which was then coated with MnO2 nanoparticles to construct PPIX-Lipo-MnO2 (PPIX-Lipo-M) in order to enhance PDT efficacy under tumor hypoxia. The PDT results show that PPIX-Lipo-M was more cytotoxic to breast cancer cells than PPIX-Lipo while under hypoxic conditions, indicating that the production of oxygen gas in hypoxic conditions improved treatment outcomes. Upon encapsulating PPIX into the liposome, the aqueous solubility of PPIX significantly improved. Consequently, the cellular uptake of both PPIX-Lipo and PPIX-Lipo-M also increased significantly compared to that of bare PPIX. Overall, PPIX-Lipo-M has the capacity to act as a therapeutic agent that relieves hypoxia and hence improve PDT efficacy.

Influence of design and operating conditions on the performance of tandem photoelectrochemical reactors

Solar-driven photoelectrochemical water splitting technology is a promising avenue for a sustainable hydrogen production. In this work, a comprehensive 2-dimensional model is developed and numerically simulated with hematite (α-Fe2O3) as the principal photoelectrode. The model evaluates light absorption, charge transport and electrochemical reactions to elucidate the effects of light transmitting materials, electrolyte height and electrolyte velocity on hydrogen and oxygen gas production. Results indicated that major losses in photocurrents are attributed to the transparent conducting oxide while losses due to the electrolyte increase with its height. Gas concentrations increase with increasing photocurrent densities and also in the direction of the flow. Gas bubbles however decrease with increasing electrolyte velocity. From these results, light reception in the reactor is uneven and poses a bigger challenge due to the bias in gas bubble distribution. Prospects of upscaling tandem schemes hence not only lie in the semiconductor material combinations but rather in the proper integration of system components and operating conditions.

USING OF THE NEW TECHNOLOGIES FOR PRODUCING MEDICAL OXYGEN AND APPLICATIONS OF IT IN MILITARY MEDICAL ORGANIZATIONS

Currently known methods of producing medical oxygen are described. The characteristics, that create restrictions or decide if one method is promising or not in the medical service, have been listed. A retrospective evaluation for the results of the science research and technical testing works carried out in the period from 2004 to 2008 in this direction military and hospital echelons of the medical service of the Russian Federation armed forces has been given. The pressure swing adsorption technology has been described. Blocks and components required to create a mobile installation for the production storage and distribution of the 93% oxygen gas at the stages of medical evacuation in military medical organization has been specified. It has been shown that the technical characteristics of the installation and quality of the 93% medical oxygen gas, depends the most on the adsorbent chosen and components of the installation in general. The creation of a domestic installation based on pressure swing adsorption technology allowing 93% medical oxygen gas production, storage and distribution to the functional units in military medicine jrganisations has been established (bibliography: 9 refs).

Modulating the electronic structure of lanthanum manganite by ruthenium doping for enhanced photocatalytic water oxidation.

To the best of our knowledge this is the first report in which ruthenium doped polycrystalline lanthanum manganite, LaMn1-xRuxO3 (x = 0.0-0.4), having high efficacy for oxygen production from water without the use of any sacrificial reagent or co-catalyst and as an efficient photocatalyst for dye degradation is reported. Ruthenium doping alters the crystal structure of the parent LaMnO3 (LMO) due to the induced chemical pressure of the larger Ru4+ ion, which facilitates a bond angle of 180° in the Mn3+-O-Mn4+ plane resulting in the easy extraction of a photo-generated charge carrier population leading to enhanced photocatalytic activity. Rietveld refinements reveal that the parent compound LMO crystallizes in the rhombohedral phase, while upon an increase in the doping concentration of ruthenium, the phase of the compounds changes from the rhombohedral to the cubic phase. The percentage contribution of each phase has been estimated using the sixth-order polynomial and pseudo-Voigt function. Typically, all the compositions, LaMn1-xRuxO3 (x = 0.0-0.4), were prepared by a conventional solid state route and studied for their photocatalytic activity. The synthesized compounds were investigated by powder X-ray diffraction (PXRD), UV-visible diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) analysis. The structure-property correlation of the compound is presented based on Rietveld refinement combined with the experimental data. The as-prepared compounds show efficient photocatalytic oxygen gas production from water without the use of any co-catalyst or sacrificial reagents. Among the five compositions, LaMn0.7Ru0.3O3 shows the highest O2 production efficiency (4.73 mmol g-1 h-1) with an apparent quantum yield (AQY) of 7.43%. These ruthenium doped compositions also exhibit superior dye degradation properties, studied by taking the industrial dye methyl orange (MO) as the model compound.

Nitrogen, Phosphorus, and Fluorine Tri-doped Graphene as a Multifunctional Catalyst for Self-Powered Electrochemical Water Splitting.

Electrocatalysts are required for clean energy technologies (for example, water-splitting and metal-air batteries). The development of a multifunctional electrocatalyst composed of nitrogen, phosphorus, and fluorine tri-doped graphene is reported, which was obtained by thermal activation of a mixture of polyaniline-coated graphene oxide and ammonium hexafluorophosphate (AHF). It was found that thermal decomposition of AHF provides nitrogen, phosphorus, and fluorine sources for tri-doping with N, P, and F, and simultaneously facilitates template-free formation of porous structures as a result of thermal gas evolution. The resultant N, P, and F tri-doped graphene exhibited excellent electrocatalytic activities for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The trifunctional metal-free catalyst was further used as an OER-HER bifunctional catalyst for oxygen and hydrogen gas production in an electrochemical water-splitting unit, which was powered by an integrated Zn-air battery based on an air electrode made from the same electrocatalyst for ORR. The integrated unit, fabricated from the newly developed N, P, and F tri-doped graphene multifunctional metal-free catalyst, can operate in ambient air with a high gas production rate of 0.496 and 0.254 μL s-1 for hydrogen and oxygen gas, respectively, showing great potential for practical applications.

Selectivity between Oxygen and Chlorine Evolution in the Chlor-Alkali and Chlorate Processes.

Chlorine gas and sodium chlorate are two base chemicals produced through electrolysis of sodium chloride brine which find uses in many areas of industrial chemistry. Although the industrial production of these chemicals started over 100 years ago, there are still factors that limit the energy efficiencies of the processes. This review focuses on the unwanted production of oxygen gas, which decreases the charge yield by up to 5%. Understanding the factors that control the rate of oxygen production requires understanding of both chemical reactions occurring in the electrolyte, as well as surface reactions occurring on the anodes. The dominant anode material used in chlorate and chlor-alkali production is the dimensionally stable anode (DSA), Ti coated by a mixed oxide of RuO2 and TiO2. Although the selectivity for chlorine evolution on DSA is high, the fundamental reasons for this high selectivity are just now becoming elucidated. This review summarizes the research, since the early 1900s until today, concerning the selectivity between chlorine and oxygen evolution in chlorate and chlor-alkali production. It covers experimental as well as theoretical studies and highlights the relationships between process conditions, electrolyte composition, the material properties of the anode, and the selectivity for oxygen formation.

Integration of platinum nanoparticles with a volumetric bar-chart chip for biomarker assays.

Platinum nanoparticles (PtNPs) efficiently catalyze the transformation of H2 O2 into oxygen gas. However, owing to the lack of an efficient approach or device that can measure the produced oxygen gas, the catalytic reaction has never been used for diagnostic applications. Microfluidics technology provides a platform that meets these requirements. The volumetric bar-chart chip (V-Chip) volumetrically measures the production of oxygen gas by PtNPs and can be integrated with ELISA technology to provide visible and quantitative readouts without expensive instrumentation or complicated data processing. Herein we show that PtNPs outperform catalase with respect to stability at high H2 O2 concentrations or temperatures or in long-term reactions, and are resistant to most catalase inhibitors. We also show that the catalase-like activity of PtNPs can be used in combination with the V-Chip to sensitively and specifically detect cancer biomarkers both in serum and on the cell surface.

Integration of Platinum Nanoparticles with a Volumetric Bar‐Chart Chip for Biomarker Assays

AbstractPlatinum nanoparticles (PtNPs) efficiently catalyze the transformation of H2O2 into oxygen gas. However, owing to the lack of an efficient approach or device that can measure the produced oxygen gas, the catalytic reaction has never been used for diagnostic applications. Microfluidics technology provides a platform that meets these requirements. The volumetric bar‐chart chip (V‐Chip) volumetrically measures the production of oxygen gas by PtNPs and can be integrated with ELISA technology to provide visible and quantitative readouts without expensive instrumentation or complicated data processing. Herein we show that PtNPs outperform catalase with respect to stability at high H2O2 concentrations or temperatures or in long‐term reactions, and are resistant to most catalase inhibitors. We also show that the catalase‐like activity of PtNPs can be used in combination with the V‐Chip to sensitively and specifically detect cancer biomarkers both in serum and on the cell surface.

Energy-Efficient and Environmentally Friendly Solid Oxide Membrane Electrolysis Process for Magnesium Oxide Reduction: Experiment and Modeling

This paper reports a solid oxide membrane (SOM) electrolysis experiment using an LSM(La0.8Sr0.2MnO3-δ)-Inconel inert anode current collector for production of magnesium and oxygen directly from magnesium oxide at 1423 K (1150 °C). The electrochemical performance of the SOM cell was evaluated by means of various electrochemical techniques including electrochemical impedance spectroscopy, potentiodynamic scan, and electrolysis. Electronic transference numbers of the flux were measured to assess the magnesium dissolution in the flux during SOM electrolysis. The effects of magnesium solubility in the flux on the current efficiency and the SOM stability during electrolysis are discussed. An inverse correlation between the electronic transference number of the flux and the current efficiency of the SOM electrolysis was observed. Based on the experimental results, a new equivalent circuit of the SOM electrolysis process is presented. A general electrochemical polarization model of SOM process for magnesium and oxygen gas production is developed, and the maximum allowable applied potential to avoid zirconia dissociation is calculated as well. The modeling results suggest that a high electronic resistance of the flux and a relatively low electronic resistance of SOM are required to achieve membrane stability, high current efficiency, and high production rates of magnesium and oxygen.

Solution processed transparent nanoparticulate ZnO thin film electrode for photoelectrochemical water oxidation

A solution processed synthetic route has been developed for making transparent ZnO thin film having nanoparticle size of around 21 nm. Without additional modification ZnO films shows current density of 1 mA cm−2. The films also exhibit the production of oxygen gas from photo electrochemical water oxidation.