Substantial improvement is needed in efficient and affordable decolorization and disinfection methods to solve the issues caused by dyes and harmful bacteria in water and wastewater. This work involves the photocatalytic degradation of methylene blue (MB) as well as gram-negative and gram-positive bacteria by cobalt-doped tin oxide (Co-SnO₂) nanoparticles (NPs) and Co-SnO₂/SGCN (sulfur-doped graphitic carbon nitride) nanocomposites (NCs) under sunlight. The coprecipitation approach was used to synthesize the photocatalysts. Maximum methylene blue (MB) photocatalytic degradation was seen with the 7% Co-SnO₂ NPs compared to other (1, 3, 5, and 9 wt.%) Co-SnO₂ NPs. The 7% Co-SnO₂ NPs were then homogenized with different amounts (10, 30, 50, and 70 weight %) of sulfur-doped graphitic carbon nitride (SGCN) to develop Co-SnO₂/SGCN heterostructures with the most significant degree of MB degradation. The synthesized samples were identified by modern characterization methods such as FT-IR, SEM, EDX, UV-visible, and XRD spectroscopies. The Co-SnO₂/50% SGCN composites showed a significant increase in MB degradation and degraded 96% of MB after 150 min of sunlight irradiation. Both gram-negative (E. coli) and gram-positive (B. subtiles) bacterial strains were subjected to antibacterial activity. All samples were shown to have vigorous antibacterial activity against gram-positive and gram-negative bacteria, but the Co-SnO₂/50% SGCN composites exhibited the maximum bactericidal action. Thus, the proposed NC is an efficient organic/inorganic photocatalyst that is recyclable and stable without lowering efficiency. Hence, Co-SnO₂/50% SGCNNC has the potential to be employed in water treatment as a dual-functional material that simultaneously removes organic pollutants and eradicates bacteria.

Wastewater from many sectors that contains hazardous organic pollutants exacerbates environmental contamination. Consequently, outstanding photocatalytic substances that can successfully degrade hazardous substances are needed to provide pollution-free water. From this perspective, zinc oxide/g-C₃N₄-based composites are desirable due to their low cost, strong reactivity, and environmental friendliness. So, in the current investigation, sequences of Mn/g-C₃N₄/ZnO (Mn/GZ) and Ni/g-C₃N₄/ZnO (Ni/GZ) nanocomposites (NCs) containing different concentrations (wt.%) of g-C₃N₄ were made via the co-precipitation process. The chemical makeup and morphological characteristics of the produced composites were ascertained via the techniques of transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Fourier transform infrared (FTIR), photoluminescence (PL), and UV spectrophotometry. Methyl orange (MO) and Eriochrome Black T (EBT) dyes were used as target pollutants to assess the composite materials’ photocatalytic effectiveness. Compared to g-C₃N₄/ZnO and g-C₃N₄, the produced Mn/GZ and Ni/GZ NCs displayed better photocatalytic activity. The improved photocatalytic efficiency of the Ni/GZ and Mn/GZ NCs might be credited to synergistic interactions at the g-C₃N₄ and ZnO interface that result in a more efficient separation and conduction of photo-induced charges. Furthermore, the Ni/Mn atoms act as the facilitators to improve electron–hole pair separation and conduction in NCs. The nanocomposites were found to be incredibly stable, with consistently high dye decoloration efficiency over five catalytic cycles. Hence, Ni/GZ and Mn/GZ could potentially be very effective and adaptable photocatalysts for the photocatalytic decoloration of wastewater pollutants.

Efficient energy storage strategies have become a major priority in the last few years. Transition metal sulphides are popularly known as attractive electrode materials or supercapacitors due to their high theoretical capacitance, excellent electrical conductivity, and favourable redox properties. Through compositional and structural engineering, some transition metal sulphides like Mn, V, Co, Fe, Cu, Ni, Mo, Zn, W, and Sn have shown substantial improvements in electrochemical performance. Composite engineering and morphological control are two of the key strategies employed to improve the TMS electrode’s electrochemical performance. Excellent electrochemical TMSs address the issues of slow kinetics, poor stability, and large volume expansions. This study reveal optimised TMSs potential to transform supercapacitor applications and provides viable approaches to conquer current hurdles to shape the forthcoming century’s high-performance and low-cost energy storage technology. The effects of composite engineering and morphological control on the ultimate electrochemical performance of the electrode materials are the primary focus of this investigation. Challenges to the further advancement of transition metal sulphide-based electrode materials are also explored in this article. Critical approaches to resolving significant issues in our current understanding of the kinetic and mechanistic perspectives of charge storage processes, i.e., slow kinetics, poor stability, and volume expansions, are also highlighted. Ultimately, future potentials, challenges, and possible solutions to tackle these problems are broadly discussed.

Gulf countries experience an imbalance between water supply and demand, which leads to a dramatic decline in the amount of groundwater. Solar energy for water desalination is an attractive option in this region, where the climate is sunny all year. A very basic solar device called a single basin solar still is commonly used to convert available seawater into drinkable water. The issue of producing drinking water may be resolved by using this technique, but because of its low productivity, it is rarely used. The experiments were carried out on a south-facing, single slope solar still with a 23-degree inclination of the condensing cover from October to November 2022, on different days for different water depths. According to the findings, the solar still with 4 cm of depth (as compared to 5, 6, and 7 cm) exhibited the maximum water productivity (2.680 L/day) with an efficiency of 30%. When the solar still was equipped with an external mirror, the temperature in the basin was raised, and water productivity increased to 3.075 L/day with an improved efficiency of 35%. Further, the effects of wind velocity, ambient temperature, inner glass temperature, and intensity of solar radiation on daily productivity have been studied.