The Impact of Co Doping and Annealing Temperature on the Electrochemical Performance and Structural Characteristics of SnO2 Nanoparticulate Photoanodes

Abstract

Obtaining H2 energy from H2O using the most abundant solar radiation is an outstanding approach to zero pollution. This work focuses on studying the effect of Co doping and calcination on the structure, morphology, and optical properties of spin-coated SnO2 films as well as their photoelectrochemical (PEC) efficiency. The structures and morphologies of the films were investigated by XRD, AFM, and Raman spectra. The results confirmed the preparation of SnO2 of the rutile phase, with crystallite sizes in the range of 18.4–29.2 nm. AFM showed the granular structure and smooth surfaces having limited roughness. UV-Vis spectroscopy showed that the absorption spectra depend on the calcination temperature and the Co content, and the films have optical bandgap (Eg) in the range of 3.67–3.93 eV. The prepared samples were applied for the PEC hydrogen generation after optimizing the sample doping ratio, using electrolyte (HCl, Na2SO4, NaOH), electrode reusability, applied temperature, and monochromatic illumination. Additionally, the electrode stability, thermodynamic parameters, conversion efficiency, number of hydrogen moles, and PEC impedance were evaluated and discussed, while the SnO2 films were used as working electrodes and platinum sheet as an auxiliary or counter electrode (2-electrode system) and both were dipped in the electrolyte. The highest photocurrent (21.25 mA/cm2), number of hydrogen moles (20.4 mmol/h.cm2), incident photon-to-current change efficiency (6.892%@307 nm and +1 V), and the absorbed photon-to-current conversion efficiency (4.61% at ~500 nm and +1 V) were recorded for the 2.5% Co-doped SnO2 photoanode that annealed at 673 K.

Nanocomposite Electrode of Titanium Dioxide Nanoribbons and Multiwalled Carbon Nanotubes for Energy Storage

“…The average crystallite size, CS, was determined using the Scherrer equation where is the full width at half maximum (FWHM); is the Bragg’s angle in radians; and λ is the X-ray wavelength (CuK α = 0.15405 nm) [ 25 , 26 ]. Additionally, the dislocation density (δ) was determined by applying Williamson and Smallman’s relation, where N = 1 represents the minimum dislocation density and δ = .…”

“…Additionally, the dislocation density (δ) was determined by applying Williamson and Smallman’s relation, where N = 1 represents the minimum dislocation density and δ = . Using Equation (1), the texture coefficient (TC) was also calculated from the data [ 25 , 26 ]. where N is the number of reflections and I r = is the difference between the measured intensity I( hkl ) and the standard intensity I o ( hkl ) for the plane hkl .…”

Fabrication of ZnO/ZnAl2O4/Au Nanoarrays through DC Electrodeposition Utilizing Nanoporous Anodic Alumina Membranes for Environmental Application

“…The Scherrer equation, CS = 0.94 λ β cos θ , was used to obtain the crystallite size (CS) from the XRD chart, wherein the full width at half maximum (FWHM), Bragg's angle in radians, and X-ray wavelength (CuK α = 0.15418 nm) are presented by β, θ, and λ, respectively [42,43]. Williamson and Smallman's relation, δ = N CS 2 , was also used to calculate the dislocation density (δ), where N = 1 denotes the minimal dislocation density.…”

“…The hot spots were converted into completely occupied MB or MO sites by prolonging the contact duration between the adsorbent and adsorbate. There is an increase in the repulsive forces between dye molecules in the bulk liquid phase and dye molecules adsorbed on adsorbent surfaces as a result [42]. In the case of MB, the rate of adsorption is greater than that of MO.…”

Influence of Annealing Time on the Optical and Electrical Properties of Tin Dioxide-Based Coatings

“…It is a semiconductor material with a unique characteristic of high optical transparency in the visible range of electromagnetic radiation and low electrical resistance [3,4]. Tin dioxide has numerous applications, serving as a gas-trapping layer in various gas sensors [5,6], an effective photoanode [7,8], a protective coating against corrosion [9,10], an antibacterial coating [11,12], an anode for high-performance lithium-ion batteries [13,14] and for various other purposes. Tin dioxide also has medical applications, such as serving as a glucose sensor [15,16].…”