Researchers have recently paid a lot of attention to semiconductor photocatalysts, especially ZnO-based heterostructures. Due to its availability, robustness, and biocompatibility, ZnO is a widely researched material in the fields of photocatalysis and energy storage. It is also environmentally beneficial. However, the wide bandgap energy and quick recombination of the photoinduced electron–hole pairs of ZnO limit its practical utility. To address these issues, many techniques have been used, such as the doping of metal ions and the creation of binary or ternary composites. Recent studies showed that ZnO/CdS heterostructures outperformed bare ZnO and CdS nanostructures in terms of photocatalytic performance when exposed to visible light. This review largely concentrated on the ZnO/CdS heterostructure production process and its possible applications including the degradation of organic pollutants and hydrogen evaluation. The importance of synthesis techniques such as bandgap engineering and controlled morphology was highlighted. In addition, the prospective uses of ZnO/CdS heterostructures in the realm of photocatalysis and the conceivable photodegradation mechanism were examined. Lastly, ZnO/CdS heterostructures’ challenges and prospects for the future have been discussed.

Nickel-Phosphate/Boron (Ni-P/B) electroless coatings have been widely used to improve physical and mechanical properties in various industrial applications, including the automotive, aerospace, chemical processing, food, oil and gas, electronic, textile, and printing industries. Electroless nickel coatings are one of the most popular surface-coating methods due to their low cost and short processing time. The purpose of this review is to look at several coating materials and the existing processes for making electroless coatings on different materials. The improvement of Ni-P/B composite coatings by the incorporation of secondary particles into an alloy matrix at the macro, micro, and nano levels is explained in detail. Process parameters like type of surfactant, annealing temperature, size of the reinforcement material, and reducing-agent percentage on mechanical characteristics like hardness, high-temperature oxidation behaviour, friction, coefficient, wear, and corrosion have been broadly researched and illustrated clearly.

Electroless nickel–phosphorus (EN) coatings are extensively used in various industrial applications to improve the mechanical and physical properties such as hardness, wear, and corrosion resistance. Heat treatment process and the addition of nanosized metallic/ceramic particles further improve the properties of the coating. The aim of the current research is to study the influence of heat treatment temperature, the proportion of ZnO nanoparticles on microhardness, and corrosion behaviour of EN coatings. Different amounts of ZnO nanoparticles were added to electroless bath by using Ultrasonicator to develop composite coatings. The microhardness and corrosion resistance of the coatings were further analysed through the experiments. Characterisation of the deposited coatings is carried out by using scanning electron microscopy and X-ray diffraction studies. The combination of heat treatment temperature and concentration of ZnO particles in EN bath to achieve maximum microhardness and corrosion resistance is studied.