Advances in Co3O4 nanomaterial-based photocatalysts for water purification: mechanisms, green synthesis, activation of oxidants, waste-derived sources, and computational insights

Abstract

Water scarcity remains a critical global challenge, affecting billions of people and significantly impacting ecosystems, economies, and public health. Among various water treatment technologies, photocatalysis has emerged as a highly effective method for degrading a wide range of contaminants. Cobalt oxide (Co₃O₄) has gained considerable attention as a photocatalyst due to its unique structural, electronic, and optical properties. Despite extensive research on the synthesis and application of Co₃O₄-based photocatalysts, a comprehensive review summarizing recent advancements and modifications in Co₃O₄ nanomaterials over the past five years is notably lacking. This review critically examines the fundamental photocatalytic mechanisms of Co₃O₄ nanomaterial-based systems, systematically discussing their advantages and inherent limitations. Additionally, it explores emerging research trends, including biosynthesis, facile recovery, synthesis from waste-derived sources, and computational techniques, alongside the prevailing challenges shaping this field. Furthermore, the review identifies key research directions for the future development and optimization of Co₃O₄-based nanostructures, emphasizing their potential to enhance photocatalytic efficiency for water purification. By addressing these aspects, this work aims to bridge existing knowledge gaps and provide a foundation for future innovations in sustainable water treatment technologies.