Providing functional photocatalysts (PCs) is truly necessary for converting solar energy into sustainable energy sources. The use of noble metals has been a cornerstone in efforts to develop processes due to their renowned capability to create catalysts that are highly active, selective, and durable. However, mounting concerns about their cost and scarcity have led to research efforts toward developing noble metal-free photocatalysts. The development of viable substitute PCs using components that are widely accessible on Earth is, therefore, the subject of increased research and development. There have been far more reports of Earth-abundant PCs lately. Abundant transition metals, such as specific complexes based on nickel (II), iron (II), cobalt (III), copper (I), and zinc (II), have been reported in notable ways. This chapter discusses the traditional and environmentally friendly synthesis of photocatalysts using Earth-abundant metal-based nanostructured photocatalysts, emphasizing the significant advantages in the production of renewable energy, water purification, and improved air quality. The rest of this section presents a summary of the development of nanostructured photocatalysts, serving as a useful reference for researchers and experts in chemistry, materials science, and renewable energy.