This study investigated the use of ethylene glycol to form α-MoO₃ (molybdenum trioxide) from ammonium molybdate tetrahydrate at various sintering temperatures for 1 h. During the sintering process, the morphologies of the constituents were observed using scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy was used to explain the reaction process. In this work, the results obtained using X-ray photoelectron spectroscopy (XRD) demonstrated that, when the molybdenum trioxide powder was treated thermally at 300 °C, the material exhibited crystallinity. The peaks were indexed to correspond with the (110), (040), (021), (111), and (060) crystallographic planes, and the lattice parameters of a, b, and c were about 3.961, 13.876, and 3.969 Å. Using these observations, we confirmed that orthorhombic α-MoO₃ was formed for sintering temperatures from 300 to 700 °C. Pattern images were obtained by the selected area electron diffraction pattern (SAED) technique, and the d distance of the high resolution transmission electron microscopy (HRTEM) images were almost 0.39 and 0.36 nm, and the Mo 3d_5/2, Mo 3d_3/2, and O 1s of X-ray photoelectron spectroscopy (XPS) were located at 233.76, 237.03, and 532.19 eV, which also demonstrated that α-MoO₃ powder had been synthesized.

Photocatalytic hydrogen (H₂) production by water splitting provides an alternative to fossil fuels using clean and renewable energy, which gives important requirements about the efficiency of photocatalysts, co-catalysts, and sacrificial agents. To achieve higher H₂ production efficiencies from water splitting, the study uses different metals such as yttrium (Y), praseodymium (Pr), magnesium (Mg), Indium (In), calcium (Ca), europium (Eu), and terbium (Tb) doped lanthanum iron oxide (LaFeO₃) perovskites. They were synthesized using a co-precipitate method in a citric acid solution, which was loaded with the rhodium chromium oxide (RhCrO_x) cocatalysts by an impregnation method along with a detailed investigation of photocatalytic hydrogen evolution performance. Photoluminescence (PL) and UV–Vis diffuse reflectance spectra (DRS) measured the rate of electron–hole recombination for RhCrO_x/Pr-LaFeO₃ photocatalysts, and X-ray powder diffraction (XRD), scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM), and X-ray photoelectron spectra (XPS) analyzed their characteristics. The experimental results obtained show that the samples with 0.5 wt.% RhCrO_x loading and 0.1 M Pr-doped LaFeO₃ calcined at a temperature of 700 °C (0.1Pr-LaFeO₃-700) exhibited the highest photocatalytic H₂ evolution rate of 127 µmol h⁻¹ g⁻¹, which is 34% higher photocatalytic H₂ evolution performance than undoped LaFeO₃ photocatalysts (94.8 μmol h⁻¹ g⁻¹). A measure of 20% of triethanolamine (TEOA) enabled a high hole capture capability and promoted 0.1-Pr-LaFeO₃-700 to get the highest H₂ evolution rate.

Nanostructured iron disulfide (FeS₂) was uniformly deposited on regenerated cellulose (RC) and oxidized carbon nanotube (CNT)-based composite films using a simple chemical bath deposition method to form RC/CNT/FeS₂ composite films. The RC/CNT composite film served as an ideal substrate for the homogeneous deposition of FeS₂ microspheres due to its unique porous architecture, large specific surface area, and high conductivity. Polypyrrole (PPy), a conductive polymer, was coated on the RC/CNT/FeS₂ composite to improve its conductivity and cycling stability. Due to the synergistic effect of FeS₂ with high redox activity and PPy with high stability and conductivity, the RC/CNT/FeS₂/PPy composite electrode exhibited excellent electrochemical performance. The RC/CNT/0.3FeS₂/PPy-60 composite electrode tested with Na₂SO₄ aqueous electrolyte could achieve an excellent areal capacitance of 6543.8 mF cm^-2 at a current density of 1 mA cm^-2. The electrode retained 91.1% of its original capacitance after 10,000 charge/discharge cycles. Scanning electron microscopy (SEM) images showed that the ion transfer channels with a pore diameter of 5-30 μm were formed in the RC/CNT/0.3FeS₂/PPy-60 film after a 10,000 cycle test. A symmetrical supercapacitor device composed of two identical pieces of RC/CNT/0.3FeS₂/PPy-60 composite electrodes provided a high areal capacitance of 1280 mF cm^-2, a maximum energy density of 329 μWh cm^-2, a maximum power density of 24.9 mW cm^-2, and 86.2% of capacitance retention after 10,000 cycles at 40 mA cm^-2 when tested at a wide voltage window of 1.4 V. These results demonstrate the greatest potential of RC/CNT/FeS₂/PPy composite electrodes for the fabrication of high-performance symmetric supercapacitors with high operating voltages.