Estimated Band Gap Research Articles

Effect of Thermal Annealing on Photocatalytic Properties of BiFeO3 Thin Films

Improving photocatalytic activity of traditional photocatalysts is one of the actual topics. We fabricated the single phase multiferroic BiFeO3 thin films on SiO2/Si substrates using sol_gel method and analyzed the effect of thermal annealing on photocatalytic properties of the film. Experimental results show that all the samples had a single perovskite rhombohedral structure and are randomly oriented. The estimated band gap values of the films are 2.63, 2.88, and 2.92 eV, respectively. BiFeO3 thin films show good photocatalytic properties in the degradation of methylene blue solution under visible-light irradiation. These results indicate that the microstructure, optical, and photocatalytic properties of BiFeO3 thin films have a strong dependence on annealing temperature. We hope that this work could provide a new route for preparation of highly efficient photocatalysts.

Computational analysis to study the effect of infusion of Tetracyanoquinodimethane in zinc based metal-organic framework

The present study reports the computational analysis of band structures and density of state (DOS) profiles of a Tetracyanoquinodimethane (TCNQ) infused IRMOF-1 (Iso Reticular Metal-Organic Framework-1). IRMOF-1 is a zinc-based MOF and has been reported useful in literature for a variety of applications, including gas storage and sensing owing to its highly porous structure. We have adopted a SIESTA based computational investigation approach to investigate the tuning of the band structure and DOS of IRMOF-1 via the infusion of a redox active species, i.e., TCNQ. The results have highlighted that the doping of TCNQ in IRMOF-1 is useful for the realization of a novel material with an estimated band gap of 4.35 eV. The necessary computational steps involved various optimization steps, such as the optimization of mesh-cutoff, lattice constant, lattice volume, and conjugate gradient. These computation studies have thus established that an approach of doping IRMOF-1 with TCNQ can result in the development of a suitably functional porous material that can be further exploited as an ultrawide‐bandgap semiconductor material or for the electrochemical sensing of different analytes, such as gases.

Nanostructures of tin oxide by a simple chemical route: synthesis and characterization

Tin oxide (SnO2) nanostructures have been synthesized by a simple chemical route. The morphology and crystallization of the samples can be controlled by changing the mixed solution of tin chloride. The precursors were calcined at 600 °C for 2 h in air to obtain the SnO2 nanorods and nanoparticles. The phase composition of the samples was investigated by XRD and electron diffraction analysis. The results confirmed the formation of a SnO2 phase with tetragonal structure. The optical properties of the nanostructures were investigated by UV-vis spectroscopy. The estimated band gaps of nanorods and nanoparticles were 3.39 and 4.23 eV, respectively. The results revealed that the morphologies and band gaps of the samples varied with the mixed solution of tin chloride.

Ellipsometric evaluation and morphology of mixed zinc sulfide/zinc oxide and zinc oxide nanostructures synthesized at various temperatures

The aim of this work was to carry out systematic studies of how synthesis temperatures affect the morphology and properties of mixed zinc sulfide/zinc oxide (ZnSxOy and ZnO) nanostructures, and to get reliable data on optical constants of ZnSxOy and ZnO nanowires/nanobelts (NW/NB) for the use in device applications. ZnSxOy and ZnO NWs/NBs were fabricated using vapor transport in an open-end tube. Mixed ZnS0.47O0.62NWs was obtained at the synthesis temperature of 850 °C. The sulfur content disappeared as the temperature increased to 950 °C and 1050 °C and the morphology changed to a mixture of NW/NB. The NW prepared at 850 °C were indexed as mixed phases of hexagonal ZnS and hexagonal ZnO structures. The NW/NB prepared at 950 °C and 1050 °C were indexed as pure hexagonal ZnO structures. The thickness, surface roughness, and optical constants of the synthesized nanostructured samples were extracted from measurements of spectroscopic ellipsometry. A two-layers model was proposed to fit the calculated data to the measured ellipsometric spectra. The estimated band gap values of the prepared nanostructures lay 0.66–0.79 eV below the bulk ZnO value due to the lower oxygen content present in the samples and the stresses built in the samples during preparation.

Facile synthesis of mesoporous TiO2-CdS-polyaniline ternary system with improved optical properties

In this work the new ternary system, mesoporous TiO2-CdS modified with polyaniline (PANI), was synthesized in a one-step strategy. Firstly, TiO2 nanorods were prepared by hydrothermal method, secondly, mesoporous CdS was deposited by successive ionic layer adsorption and reaction (SILAR) process in a surfactant free nonaqueous solvent and in the same time the TiO2-CdS binary hybrid was sensitized with polyaniline to produce the TiO2-CdS-PANI ternary system for the first time. The synthesized samples were characterized via various technics such as x-ray diffraction, field emission scanning electron microscopy, high resolution transmission electron microscopy, energy dispersive x-ray spectroscopy, UV–vis diffuse reflectance spectroscopy, and Brunauer–Emmett–Teller (BET) analysis. XRD and EDX analysis of the binary hybrid confirmed the coating of TiO2 with CdS using SILAR method. FESEM and HRTEM images illustrated the formation of CdS particles over the TiO2 rods. Compared to the unmodified TiO2, TiO2-CdS binary system can absorb all wavelengths below ∼515 nm, whereas the ternary nanocomposite shows absorption capability in all the UV and visible region owing to the contribution of both CdS and PANI. The estimated band gap energy of unmodified TiO2, TiO2 sensitized with CdS, ternary system is decreased from 3.18 eV to 2.32 eV and 1.12 eV, respectively. Additionally, the adsorption desorption isotherm of the binary hybrid proved its mesoporous structure. Furthermore, the TiO2-CdS-PANI ternary nanocomposite has higher specific surface area than its corresponding binary system. Finally, the possible mechanism for enhancing the photocatalytic activity of the ternary system was proposed.

Synthesis, Molecular Structure and Theoretical Investigation of Optical and Electronic Properties of New Crystalline Polymer: [(C6H5NH3)2Cd(SCN)2Cl2

A new crystalline polymer compound {(C6H5NH3)2Cd(SCN)2Cl2}n was synthesized and analyzed using single crystal XRD,UV–Vis spectroscopy. The crystal structure refinement shows that this ionic material crystallizes at 298 K in the monoclinic system (C2/c space group). The cohesion and the stability of the polymeric structure is assured by (i) the establishment of N–H···Cl and N–H···N (NCS) hydrogen bonding contacts between the (C6H5NH3)+ cations and the [Cd(SCN)2Cl2] n 2n− chains, (ii) the π–π interactions between the centroids of the phenyl rings of (C6H5NH3)+ cations and (iii) the C(6)–H(6)···π (phenyl) interactions. The indirect optical band gap energy deduced from the UV–Vis spectroscopy is Eg = 3.91 eV. Electronic structure, and optical properties were determined using density functional theory (DFT) calculations. The atomic coordinates and the lattice parameters were optimized while the space group symmetry was kept fixed during the refinements. The estimated band gap between HOMO and LUMO calculation is 3.67 eV. Moreover in order to understand the optical properties of {(C6H5NH3)2Cd(SCN)2Cl2}n, the dielectric function, optical reflectivity, refractive index, optical conductivity and electron energy loss are calculated and discussed for radiation up to 38 eV.

Ternary system from mesoporous CdS–ZnS modified with polyaniline for removal of cationic and anionic dyes

In this work, mesoporous CdS (130.7 m2/g) was prepared; then, ZnS was deposited by chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR) method, to get CdS–ZnS(C) and CdS–ZnS(S), respectively. Subsequently, the highest efficient binary hybrid was sensitized with polyaniline to produce CdS–ZnS–PANI for the first time. XRD and EDX analyses confirmed the coating of CdS with ZnS using CBD and SILAR method. The careful examination for the surface morphology of the binary hybrids illustrated that CdS–ZnS(S) has uniform morphology and the CdS nanoparticles are homogeneously overcoated with ZnS. In contrast, CdS–ZnS(C) exhibits inhomogeneous surface, where there are ZnS particles that aggregate together and there is another region which contains ZnS deposited onto CdS. The estimated band gap of CdS, CdS–ZnS(S), and CdS–ZnS–PANI was 2.36 eV, 2.44 eV, and 1.9 eV, respectively. The removal efficiency for cationic and anionic dyes single and/or in combination using CdS, ZnS, CdS–ZnS(C), CdS–ZnS(S), PANI, and CdS–ZnS–PANI was studied. The effect of the amount of ZnS loaded by SILAR process on the activity of the CdS–ZnS(S) was presented. The results proposed that CdS–ZnS(S) exhibits selective adsorption and high removal efficiency for cationic dye compared to CdS–ZnS(C) due to higher negative zeta potential and large surface area. The CdS–ZnS–PANI ternary nanocomposite showed uptake efficiency of 96.7% for cationic dye (MB) and 94.3% for anionic dye (MO) in a mixed dye solution after 10 min. Finally, the possible adsorption mechanism was proposed.

First principles studies of CsLnCdTe3 (Ln = Gd−Tm) for green energy resources

The structural, electronic, optical and thermoelectric properties of alkali metal cadmium telluride CsLnCdTe3 (Ln = Gd–Tm) semiconductors are investigated using density functional theory. The structural parameters are calculated using generalized gradient approximation which show a close agreement with experimental values. The electronic properties are investigated using GGA + U approximation because the Hubbard potential (U) gives better results and are very reliable for band structure calculations. The predicted band gaps show direct band gap nature. The estimated band gap of CsTmCdTe3 is 1.93 eV which is in agreement with the experimental value of 2.01 eV. The narrow band gaps, high dielectric constants and high absorption ranges make these materials suitable hosts for solar energy conversion applications. BoltzTrap calculations are used to obtain thermoelectric parameters like seebeck coefficient, electronic and thermal conductivity. The high seebeck effect and large power factor values confirm the efficiency of these materials in thermoelectric converter technology.

Preparation of carbon-supported CdS photocatalysts with high performance of dye photodegradation using cadmium-enriched Perilla frutescens biomass

Cadmium sulfide (CdS), which is a typical and important semiconductor, has become enormous research concern in photocatalysis for environmental remediation. However, the practical usage of CdS in photocatalysis was largely limited because of photocorrosion, and the toxic Cd2+ ions would be released which leading to the potential environmental risks. To improve this defect, specific research has been focusing on fabrication of stable CdS nanocomposites by supporting with carbon-based materials. In this study, cadmium-enriched Perilla frutescens root was selected to in situ fabricate carbon-supported CdS nanocomposite photocatalyst. It was found that the CdS@CP contained CdS nanoparticles which were indexed to mixed-phase cubic and hexagonal CdS. Estimated band gap energy of CdS@CP (2.21 eV) was obviously lower than the pure CdS (2.57 eV), which implying that the new synthesis of CdS@CP was more easily to be motivated by visible light and required less energy compared with pure CdS. Moreover, the photodegradation rate of Rhodamine B (RhB) by CdS@CP was ca. 98%, and it exhibited high catalytic performance and durability in photodegradation of dye. The synthesis of CdS@CP photocatalysts with high performance of dye photodegradation would be a facile and low-cost pathway for achieving high value utilization of Cd-enrich biomass.

TiO2/TiOxNY hollow mushrooms-like nanocomposite photoanode for hydrogen electrogeneration

TiO2/TiOxNy hollow mushrooms-like nanocomposite photocatalyst was prepared using atomic layer deposition (ALD) and reactive direct current magnetron sputtering, respectively. The preparation process depends on the aluminum oxide template (AOT) that was fabricated using the two-step anodization process after the Ni imprinting process. The chemical, morphological, and optical properties were recorded using different analyses such as XRD, SEM, EDX, and UV–Vis. From the SEM analyses, the AOT pore size increases from 177 to 305 nm after the pore widening process in H3PO4. The diameter of the TiO2 in the upper part is 352 nm, while the diameter of the TiO2/TiOxNy composite is 355 nm in the upper part. The estimated band gap values of TiO2 and TiO2/TiOxNy are 3.1 and 2.25 eV, respectively. From the values of band gaps, there is a clear enhancement in the optical absorption of the nanocomposite bilayers. The photoelectrochemical (PEC) behaviors of the TiO2/TiOxNy electrodes supported in Au/Ni metal thin film was measured in 1 M NaOH as scarifying reagent. The thermodynamic parameters were calculated, in which ΔE, ΔH*, and ΔS* values are 16.75 kJ mol−1, 15.87 kJ mol−1 and − 115.65 kJ mol−1 K−1, respectively.

Demonstration of tunable Ag morphology from nanocolumns to discrete nanoislands using novel angle constrained glancing angle EB evaporation technique

In glancing angle electron beam evaporation technique, the deposition geometry has been engineered in a novel manner in this work to produce extensive tunablity of Ag morphology. A physical plate (collimator) parallel to the substrate has been suitably placed in order to constrain the angle of incoming deposition vapor flux. The distance between substrate and this collimator as well as the distance between substrate to crucible orifice has been optimized for maximum variation in Ag morphology which resulted in the discussed tunability. SEM images acquired across the sample surface on the best optimized sample show variation of Ag morphology from nearly continuous film to Ag nanocolumns (dia-135 nm) and then to Ag nanoislands of varying size (26–83 nm) with the variation in height from substrate bottom edge. Surface plasmon resonance (SPR) peak of this Ag nanostructure has been found to shift to longer wavelength and to broaden with the increase of thickness across the substrate surface. The estimated band gap values of the Ag nanostructure are non-zero which reveals its dielectric like dispersion behavior. Thickness and optical constants at various locations on the best optimized sample have been estimated through spectroscopic ellipsometry measurements and the obtained results have been validated with measured transmission spectrophotometry spectra. Three different ellipsometry models have been tried to fit the ellipsometry data of such grown ultrathin film consisting of Ag nanoislands/nanocolumns. An effective media consisting of the mixture of bulk Ag, dielectric media represented by Lorentz oscillator and air was found to be the best to describe the disperision behavior of the deposited Ag film. The dielectric like dispersion behavior of Ag ultrathin film has been ascribed to localized surface Plasmon resonance (LSPR) effect of Ag nanoislands in optical wavelength region. Due to the gradual variation of thickness and optical constants across the film, the optimized film exhibits variation in average optical transmittance (600–1000 nm) from 1.1% to 91% across 40 mm distance which demonstrates its potential for application as variable optical transmission attenuator. Finally, this novel deposition flux constrainment technique has been regarded as an effective method for fabrication of tunable Ag nano-morphologies for optical and surface plasmonic applications.

Phase Stability and Compressibility of 3R-MoN2 at High Pressure

We report phase stability and compressibility of rhombohedral 3R-MoN2, a newly discovered layer-structured dinitride, using in-situ synchrotron high-pressure x-ray diffraction measurements. The obtained bulk modulus for 3R-MoN2 is 77 (6) GPa, comparable with that of typical transition-metal disulfides (such as MoS2). The axial compressibility along a axis is more than five times stiffer than that along c axis. Such strong elastic anisotropy is mainly attributed to its layered structure with loosely bonded N-Mo-N sandwich interlayers held by weak Van der Waals force. Upon compression up to ~15 GPa, a new hexagonal phase of 2H-MoN2 occurs, which is irreversible at ambient conditions. The structural transition mechanism between 3R and 2H phases is tentatively proposed to be associated with the rotation and translation of sandwich interlayers, giving rise to different layer stacking sequences in both phases. At high temperature, the decomposition of 3R-MoN2 leads to the formation of hexagonal δ-MoN and the onset degassing temperature increases as the pressure increases. In addition, the low-temperature electrical resistivity measurement indicates that 3R-MoN2 behaves as a semiconductor with an estimated band gap of Eg ≈ 0.5 eV. 3R-MoN2 also shows weak antiferromagnetic properties, which probably originates from the occurrence of magnetic zigzag edges in the structure.

Synthesis and Catalytic Application of Poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid‐co‐acrylamide) Grafted on Graphene Oxide

AbstractGraphene oxide was grafted with poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid‐co‐acrylamide) (GO–poly(AMPS–co–AM)) by free radical copolymerization of the corresponding monomers namely acrylamide (AM) and 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS). The benzoyl peroxide (BPO) was used as initiator. The GO–poly(AMPS–co–AM) was characterized by Fourier transform infrared spectroscopy (FT–IR), Raman spectroscopy, X–ray diffraction (XRD), thermal gravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscopy (SEM), energy‐dispersive X–ray spectroscopy (EDX), UV–Vis and fluorescence spectroscopy, and elemental analysis. The GO–poly(AMPS–co–AM) exhibited the acidic site loading of 0.85 mmol g−1, the maximum degradation temperatures (Tmax) of 212, 292, and 406 °C, the char yield of 30% at 800 °C, the limiting oxygen index (LOI) of 29.5, an estimated band gap of 4.7 eV, and the fluorescence emission bands of 722, 800, and 880 nm at the excitation wavelengths (λmax) of 360, 400, and 440 nm, respectively. The GO–poly(AMPS–co–AM) was used as a reusable catalyst for the preparation of 1,8‐dioxo‐octahydroxanthenes through the condensation of an aldehyde with 5,5‐dimethyl‐1,3‐cyclohexanedione (dimedone) in H2O/EtOH (1:1) as green solvents at room temperature.

Effect of yttrium ion on the properties of tri ethyl ammonium picrate single crystals

Tri Ethyl Ammonium Picrate (TEAP) and Yttrium (Y2+) ions doped single crystals were grown by slow evaporation technique at room temperature. The estimated band gap of the pure TEAP, 0.10 mol % and 0.15 mol % of Y2+ ions doped TEAP are 3.76 eV, 3.82 eV and 3.86 eV. Crystallite size of the grown materials was calculated from powder XRD as 1.456 nm for TEAP, 3.2028 nm for 0.10 mol % of Y2+ ions doped TEAP and 6.934 nm for 0.15 mol % of Y2+ ions doped TEAP single crystals. Y–O stretching mode was assigned by FTIR spectral peak at 549 cm−1. The PL excitation wavelength of the grown materials is 350 nm. The EDAX analysis confirmed by the Carbon, Nitrogen, Oxygen and Yttrium were presented in grown crystals.

Red-Shifted Absorptions of Cation-Defective and Surface-Functionalized Anatase with Enhanced Photoelectrochemical Properties.

Manipulating the atomic structure of semiconductors is a fine way to tune their properties. The rationalization of their modified properties is, however, particularly challenging as defects locally disrupt the long-range structural ordering, and a deeper effort is required to fully describe their structure. In this work, we investigated the photoelectrochemical properties of an anatase-type structure featuring a high content of titanium vacancies stabilized by dual-oxide substitution by fluoride and hydroxide anions. Such atomic modification induces a slight red-shift band gap energy of 0.08 eV as compared to pure TiO2, which was assigned to changes in titanium–anion ionocovalent bonding. Under illumination, electron paramagnetic resonance spectroscopy revealed the formation of TiIII and O2– radicals which were not detected in defect-free TiO2. Consequently, the modified anatase shows higher ability to oxidize water with lower electron–hole recombination rate. To further increase the photoelectrochemical properties, we subsequently modified the compound by a surface functionalization with N-methyl-2-pyrrolidone (NMP). This treatment further modifies the chemical composition, which results in a red shift of the band gap energy to 3.03 eV. Moreover, the interaction of the NMP electron-donating molecules with the surface induces an absorption band in the visible region with an estimated band gap energy of 2.25–2.50 eV. Under illumination, the resulting core–shell structure produces a high concentration of reduced TiIII and O2–, suggesting an effective charge carrier separation which is confirmed by high photoelectrochemical properties. This work provides new opportunities to better understand the structural features that affect the photogenerated charge carriers.

Photo-electrochemical impedance spectroscopy analysis of hydrothermally synthesized β-In2S3 thin film photo-anodes

In this study, indium sulfide (β-In2S3) thin films were synthesized on fluorine doped tin oxide (FTO) coated glass substrates by hydrothermal reactions. The hydrothermal reaction time (HRT) was varied from 4 to 16 h and the synthesis temperature was maintained at 160 °C. The morphological, physical and electrochemical properties of the processed In2S3 films show a clear HRT dependency. XRD analysis indicates that both crystallinity and crystal size increase as HRT increases. UV–Vis absorbance spectra analysis reveals that the HRT influence greatly the In2S3 optical properties with an estimated band gap varying from 3.6 to 2.1 eV. We present as well, the influence of the HRT on the photo-electrochemical performances of In2S3 based photo-anodes investigated with electrochemical impedance spectroscopy (EIS). In2S3 photo-anodes with a photocurrent as high as 1 mA cm−2 at 0.5 V were prepared for a HRT equal to 12 h. These experimental findings promote the hydrothermal method as a simple, low cost and low temperature route allowing the preparation of β-In2S3 thin films on FTO glass suitable for photo-electrochemical applications.

Effect of cerium doping on the structural, optical and photocatalytic properties of SnO2 thin films prepared by spray pyrolysis method

In the present work, we have studied the effect of Ce doping on the physical properties of Ce-doped SnO2 thin films obtained by spray pyrolysis on heated glass substrates at 480 °C during 3 min as time deposition. Specific parameters were used to prepare the chemical solution. The structural, optical and electrical properties as well as photocatalytic behavior of Ce-doped SnO2 thin films under different Ce concentrations (0–10 wt%) were investigated. XRD patterns reveal that undoped and Ce-doped SnO2 thin films are polycrystalline with both tetragonal and cubic phases, except the thin film doped at 4 wt% presents a predominant cubic structure with preferential orientation along [111] axis. The crystallite size was affected by Ce doping and was found in the range from 35.64 to 63.12 nm. The surface morphology of films examined by atomic force microscopy (AFM) shows a texture of grains and a weak roughest (4.74 nm) for the 2 wt% Ce-doped film. The average optical transmittance of the fabricated thin films was higher than 78% in the visible range and the estimated band gap energy reached 3.99 eV. Figure of merit of Ce-doped SnO2 has a maximum value of 3.87 Ω−1 at 550 nm. The highest photocatalytic degradation (19.10%) of methylene blue under UV irradiation and 100 min of exposure time is reached for the 2 wt% Ce-doped SnO2 thin film with a surface of 3.75 cm2.

Photocatalytic degradation of rhodamine B, and phenol red dyes using NiMn2O4 nanoparticles prepared by a new approach

NiMn2O4 nanoparticles have been successfully prepared through sol-gel method. The effects of different factors such as the type of solvent, and amino acid temperature were investigated on the size and morphologies of products. The smallest particle size of NiMn2O4 nanoparticles was found to be 25 nm in diameter. The magnetic properties of the samples were also measured by an alternating gradient force magnetometer (AGFM). The optical property of the desired products was investigated by UV–vis diffuse reflectance spectroscopy , and the band gap of product was computed nearly 3 eV. The estimated band gap confirms that this product may be used as a photocatalyst, so the photocatalytic test was conducted by photooxidation of dyes under ultraviolet irradiation and in the presence of NiMn2O4 nanoparricles. The results demonstrated that rhodamine B degradation was about 98 % under ultraviolet light for 80 min. Therefore, the synthesized product can be employed as an effective photocatalyst.

Effect of precipitating agent NaOH on the synthesis of SrTiO3/TiO2 heterostructure for dye-sensitized solar cells

Abstract In this work, the effect of precipitating agent NaOH on the growth of SrTiO3 blocking layer to serve as the charge recombination barrier for DSSC based TiO2 were investigated. The SrTiO3/TiO2 heterostructure was synthesized by the hydrothermal method. The structure and surface morphology of SrTiO3/TiO2 heterostructure were carried out by SEM, TEM and XRD characterization techniques. The optical band gap of TiO2 NR and SrTiO3/TiO2 heterostructure were studied by the UV–visible spectrophotometer. The estimated band gap of TiO2 nanorod and SrTiO3/TiO2 heterostructure were typically 3.0–3.1 eV. At the best condition for fabrication (0.001 M NaOH), the SrTiO3/TiO2 heterostructure photoanode achieves the highest photo-conversion efficiency of 2.68%, which is 38% higher than the bare TiO2 nanorod photoanode (1.93%). By further analysis with the EIS, the results reveals that the added SrTiO3 blocking layer is enhanced the DSSCs performance by prolonging the charge recombination and also improve the charge transfer resistance in the photoanode.

The role of pH and nitrate concentration in the wet chemical growth of nano-rods shaped ZnO photocatalyst

ZnO nano-rods were synthesised via wet chemical method at different nitrate concentration and pH value. The effect of pH and nitrate concentration on the size and morphology of the prepared ZnO photocatalysts have been investigated by particle size distribution analysis and Field emission scanning electron microscopy respectively. Additionally, UV-Visible spectroscopy and energy dispersive studies and were carried out to confirm the optical and compositional properties of the prepared ZnO powder. The estimated band gap of the as prepared ZnO photocatalysts at different pH and nitrate concentration calculated on the basis of Kubelka–Munk function was found to be in the range of ∼2.7–3.6 eV. Field emission scanning (FE-SEM) and transmission electron microscopic (TEM) observations reveal rod-like morphology. The photocatalytic activity of prepared ZnO photocatalysts was evaluated by photo degradation of the mixture of Methylene Blue (MB) and Rhodamine 6G (Rh 6G) solution under simulated solar radiation. Volume of hydrogen evolution was recorded in the presence of prepared ZnO photocatalysts in 2 h. Nitrate concentration, and pH value showed a significant effect on the optical and morphological behaviour of the prepared ZnO powdered photocatalysts.