Silicon carbonitride (SiCN) thin films were deposited on p-type silicon (Si) substrates by reactive radio-frequency magnetron sputtering using a silicon carbide (SiC) target under argon/nitrogen (Ar/N2) plasma at room temperature. Characterization by Fourier-transform infrared, electron probe micro analyzer, and X-ray photoelectron spectroscopy indicates the formation of silicon carbonitride. Diffuse reflectance data processed by way of Tauc plot analysis resolved an optical bandgap of 2.05 eV, in agreement with photoluminescence emission data. Photoelectrochemical (PEC) carbon dioxide (CO2) reduction tests were conducted under natural sunlight irradiation at a bias of −1.2 V against silver/silver chloride (Ag/AgCl) in 0.1 M sulfuric acid (H2SO4). Quantitative gas chromatography-flame ionization detector analysis showed liquid-phase selectivity toward methanol, yielding a Faradaic efficiency of 40.9%, which corresponds to a cumulative molar yield of 19.07 µmol (0.191 mmol/L) after 1 h of continuous operation. These results quantify the PEC performance of amorphous silicon carbonitride (a-SiCN)/silicon photocathodes for solar-driven carbon dioxide conversion.
Microalgae are promising renewable resources for sustainable hydrogen production, offering a pathway towards carbon-neutral energy systems and supporting the Sustainable Development Goals (SDGs). Biohydrogen production occurs through hydrogenase- and nitrogenase-mediated pathways, including direct and indirect biophotolysis, photofermentation and dark fermentation. In Chlamydomonas reinhardtii, the [FeFe]-hydrogenase HydA1 contributes approximately 75% of hydrogen evolution under anaerobic conditions, highlighting the importance of enzymatic regulation. This review examines the biological mechanisms and technological advances governing microalgal biohydrogen production, with particular emphasis on advanced bioreactor systems that improve light utilisation, gas exchange and reactor performance. Recent developments, including genetic engineering, microalgae-bacterial consortia and nanomaterial-assisted approaches, are discussed for their role in enhancing hydrogen productivity and process stability. Oxygen-tolerant HYDA variants in Chlorella sp. achieved up to 30-fold higher hydrogen production than wild-type strains, while plasma-generated mutants of C. reinhardtii exhibited 2.7–5.2-fold increases in yield. The economic feasibility, sustainability significance, SDG contributions and scale-up challenges associated with commercially viable microalgal biohydrogen production systems are also highlighted.
Perfluorooctane sulfonate (PFOS) serves as the primary ingredient in aqueous film-forming foam used for extinguishing fires. Nevertheless, PFOS is recognized as a persistent organic pollutant. Therefore, creating environmentally friendly fluorine-free foam (FFF) extinguishing agents is of great significance. To formulate fluorine-free foam extinguishing agents, a hydrocarbon surfactant (APG0810) and silicone surfactant (PMH) were chosen as the main components. To enhance the foam stability, silica aerogel was added as a foam stabiliser. The interaction mechanism between silica aerogels and surfactants was demonstrated. The results show that when the amount of silica aerogel added was 3 wt% (PA-4), the 25% drainage time was 203 s. The surface tension was slightly reduced to 23.79 mN/m, the viscosity was 3.2 mPa⋅s, and the foam height was 181 mm. The results of foam coarsening revealed that small-sized bubbles were evenly distributed. The foam solution with silica aerogel added had better stability at high temperatures. After heating for 3000 s, the residual foam of PA-4 still remained at 1/3 of the initial foam volume. Small-scale fire extinguishing experiments with 3 L of gasoline were carried out, and the fire was completely extinguished within 72 s.
The use of polymer-based nanocomposites (NCs) in which metal and metal oxide nanoparticles are combined represents a critical point of comparison owing to their improved linear optical characteristics and wide indications in optoelectronics, sensors, and medical devices. In this survey, the synthesis method casting, material properties, and optical behavior of polystyrene, polymethyl methacrylate and polyvinyl alcohol–doped NPs have been widely studied, along with many other single and bimetallic-based NCs such as aluminum, silver, and zinc oxide, the latter two of which is also discussed in much detail below. The effects of nanoparticle-specific composition, dose, and preparation on the principal optical properties such as absorbance, reflectance, refractive index, and optical conductivity are identified. The ultraviolet-shielding capacities of the composites have attracted special attention, which can help develop them as protective coatings, packaging materials, and photonic devices as interesting materials. These findings can help to point a way for further experimental development and for applied development of functional NCs.
Currently, the design of efficient multifunctional materials for supercapacitors has become imperative in the field of energy storage and conversion. Porous carbon materials derived from biomass have been widely regarded as the promising electrode materials for supercapacitors. Herein, we have prepared porous carbon materials with Chinese cabbage as the biomass precursor by a facile pyrolysis and potassium hydroxide activation process. Based on the characterisation, Chinese cabbage-derived activated carbon (CAC-3) with a hierarchical micro-/meso-/macroporous structure indicates Brunauer-Emmet-Teller surface area of similar to 953 m2/g and an average pore size of 2.27 nm. CAC-3 indicates outstanding capacitive performance of 760 F/g at 1 A/g and good rate capability as well as superior cycling stability 95.45% of initial specific capacitance after 10 000 cycles. Moreover, the supercapacitor delivers a high specific capacitance of 266.7 F/g at 1 A/g and 78.74% of the capacitance retention at 20 A/g as well as a high energy density of 53.34 Wh/kg at power density of 1200 W/kg. This study provides new insight for the exploration of novel electrode materials with multifunctional structures for green supercapacitor.
