An activated carbon (AC) with a high surface area of 4320.7 m²/g was synthesized via the chemical and thermal processing of walnut residues. The resulting activated charcoal was characterized by various techniques, including Brunauer–Emmett–Teller (BET) surface area analysis, scanning electron microscopy (SEM), and IR spectroscopy. The prepared activated carbon was studied for its capacity to adsorb CO₂ gas. When exposed to CO₂ for 60 min in a closed chamber at atmospheric pressure at 25 °C, the adsorption of a notable 301.1 mmol CO₂ (13.25 g CO₂) per gram of activated carbon was observed.

An activated charcoal with a high surface area of 4320–3800 m²/g with significant adsorption properties was prepared by the chemical and thermal processing of walnut residues. Iraqi walnut shells were sonicated with different ratios of potassium hydroxide (KOH). The mixture was then calcined at different temperatures using an electric oven until the best thermal conditions for a very high activated surface area and performance were identified. The resulting activated charcoal was further purified to remove residual KOH and metal impurities. Investigations revealed that the quality of the prepared activated charcoal was comparable to or surpassed that of commercially available counterparts in both the physical and adsorption properties. It was characterised for methylene blue degradation and the removal of heavy elements during water purification.

This work describes how conducting polymer nanocomposites can be employed as synergistic supports that significantly accelerate the rate of electro-catalysis. The nanocomposite PEDOT/nano-Co₃O₄/rGO is discussed as an example in this respect, which is specific for photo electro-catalytic oxygen (O₂) generation from water using light (PEDOT = poly (3,4-ethylenedioxythiophene); rGO = reduced graphene oxide). We show that the conducting polymer PEDOT and the conductive additive rGO may be used to notably amplify the rate of O₂-generation from water by the nano catalyst, Co₃O₄. A composite film containing the precise molar ratio 7.18 (C; PEDOT):1 (Co):5.18 (C; rGO) exhibited high photocatalytic activity (pH 12) for the oxygen evolution reaction (OER) at 0.80 V (vs. Ag/AgCl), with a current density of 1000 ± 50 μA/cm² (including a photocurrent of 500 μA/cm²), achieved after >42 h of operation under illumination with a light of intensity 0.25 sun. By comparison, the best industrial catalyst, Pt, yielded a much lower 150 μA/cm² under the same conditions. Oxygen gas was the sole product of the reaction.

Tailoring conductive polymers with inorganic photocatalysts, which provide photoinduced electron-hole generation, have significantly enhanced composites leading to excellent photoelectrodes. In this work, MnFe₂O₄ nanoparticles prepared by a hydrothermal method were combined with polyaniline to prepare mixed (hybrid) slurries, which were cast onto flexible FTO to prepare photoelectrodes. The resulting photoelectrodes were characterized by XRD, FESEM, HRTEM and UV-VIS. The photoelectrochemical performance was investigated by linear sweep voltammetry and chronoamperometry. The photocurrent achieved by MnFe₂O₄/Polyaniline was 400 μA/cm² at 0.8 V vs. Ag/AgCl in Na₂SO₄ (pH = 2) at 100 mW/cm², while polyaniline alone achieved only 25 μA/cm² under the same conditions. The best MnFe₂O₄/Polyaniline displayed an incident photon-to-current conversion efficiency (IPCE) and applied bias photon-to-current efficiency (ABPE) of 60% at 405 nm wavelength, and 0.17% at 0.8 V vs. Ag/AgCl, respectively. High and stable photoelectrochemical performance was achieved for more than 900 s in an acidic environment.

Photocatalytic materials are being investigated as effective bactericides due to their superior ability to inactivate a broad range of dangerous microbes. In this study, the following two types of bacteria were employed for bactericidal purposes: Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). The shape, crystal structure, element percentage, and optical properties of Ag₉(SiO₄)₂NO₃ were examined after it was successfully synthesized by a standard mixing and grinding processing route. Bactericidal efficiency was recorded at 100% by the following two types of light sources: solar and simulated light, with initial photocatalyst concentration of 2 µg/mL, and 97% and 95% of bactericidal activity in ultra-low photocatalyst concentration of 0.2 µg/mL by solar and simulated light, respectively, after 10 min. The survival rate was studied for 6 min, resulting in 99.8% inhibition at the photocatalyst dose of 2 µg/mL. The mechanism of bactericidal efficiency was found to be that the photocatalyst has high oxidation potential in the valence band. Consequently, holes play a significant part in bactericidal efficiency.