This mini-review focuses on the doping and heterojunction formation in ZnO-based catalysts, highlighting their impact on photocatalytic performance. ZnO, known for its unique properties such as high redox potential and stability, is widely used in photocatalytic reactions. However, it faces challenges like electron-hole recombination and insufficient visible light absorption. Doping and heterojunction formation are effective strategies to address these issues. Doping introduces mid-gap energy levels, reducing electron-hole recombination and enhancing visible light absorption. Techniques like XRD, PL, DRS-UV-vis, XPS, and STEM are used to understand the effects of dopants. Metal ions, such as manganese, cobalt, copper, silver, and iron, are commonly doped into ZnO, each with specific effects on the material's properties. For example, manganese doping creates ferromagnetic properties and oxygen vacancies, while cobalt doping enhances visible light absorption and charge transfer efficiency. Heterojunctions, particularly the staggered type, are crucial for efficient charge separation. They involve the alignment of semiconductors with different band gaps, creating built-in electric fields that inhibit recombination and facilitate electron-hole migration. The Z-scheme mechanism, involving charge transfer between semiconductors, is another effective approach, though it faces challenges like electron-hole loss due to recombination. The review also discusses the role of noble metals, such as gold and silver, in enhancing charge separation and visible light absorption through surface plasmon resonance (SPR). These materials act as electron sinks, preventing recombination and improving photocatalytic efficiency. Overall, the review emphasizes the importance of understanding and optimizing doping and heterojunction formation to enhance the photocatalytic performance of ZnO-based catalysts.This mini-review focuses on the doping and heterojunction formation in ZnO-based catalysts, highlighting their impact on photocatalytic performance. ZnO, known for its unique properties such as high redox potential and stability, is widely used in photocatalytic reactions. However, it faces challenges like electron-hole recombination and insufficient visible light absorption. Doping and heterojunction formation are effective strategies to address these issues. Doping introduces mid-gap energy levels, reducing electron-hole recombination and enhancing visible light absorption. Techniques like XRD, PL, DRS-UV-vis, XPS, and STEM are used to understand the effects of dopants. Metal ions, such as manganese, cobalt, copper, silver, and iron, are commonly doped into ZnO, each with specific effects on the material's properties. For example, manganese doping creates ferromagnetic properties and oxygen vacancies, while cobalt doping enhances visible light absorption and charge transfer efficiency. Heterojunctions, particularly the staggered type, are crucial for efficient charge separation. They involve the alignment of semiconductors with different band gaps, creating built-in electric fields that inhibit recombination and facilitate electron-hole migration. The Z-scheme mechanism, involving charge transfer between semiconductors, is another effective approach, though it faces challenges like electron-hole loss due to recombination. The review also discusses the role of noble metals, such as gold and silver, in enhancing charge separation and visible light absorption through surface plasmon resonance (SPR). These materials act as electron sinks, preventing recombination and improving photocatalytic efficiency. Overall, the review emphasizes the importance of understanding and optimizing doping and heterojunction formation to enhance the photocatalytic performance of ZnO-based catalysts.