Photocatalytic degradation technology has received much attention from researchers in the last few decades, due to its easy and cost-effective nature. A lot of review articles have been published on dyes via photocatalytic degradation, but most of the review articles lack a detailed and in-depth photocatalytic degradation mechanism of dyes. Numerous review articles are available on photocatalysis. Here, in this review article, we are mainly focused on the complete and in-depth photocatalytic degradation mechanism of four commonly used dyes such as Malachite Green, Methylene Blue, Congo Red and Rhodamine B, which will be highly useful for the new researchers that work on dyes’ photocatalytic degradation. Initially, various aspects of dyes have been included in this review article, comprehensively. The main focus was on the covalent organic framework-based photocatalysts for dyes’ photocatalytic degradation, due to their porous nature and various unique properties. Various synthesis routes and the photocatalytic performance of covalent organic frameworks and composite of covalent organic frameworks have been highlighted in this review article. In the last section of this review article, the main stimulus was the four mentioned dyes’ properties, uses, and toxicity, and the photocatalytic degradation mechanism through various paths into environmentally friendly and less-harmful compounds in the presence of photocatalysts. Factors effecting the photocatalytic degradation, economic cost, challenges and future aspects of photocatalytic technology were also included in this review article. This review article will be highly useful for those researchers that work on the photocatalytic degradation of various dyes and search for the complete degradation of complex dye molecules.

This comprehensive review extensively explores the potential applications of MXenes as versatile materials in the realm of photocatalysis, with a specific focus on their efficacy in mitigating hazardous dyes and CO₂ to less harmful and friendly by-products. The review systematically investigates the unique properties that render MXenes well-suited for photocatalytic purposes and provides a thorough examination of their current state of research. It meticulously summarizes the successes and breakthroughs achieved thus far, offering insights into the advancements that have propelled these materials into the spotlight of photocatalytic research. In addition to highlighting achievements, the review critically addresses the challenges and hurdles that impede the full realization of the potential inherent in MXenes. Here, we have also highlighted the stability problem of MXenes and how to overcome this problem for efficient photocatalysis. The mechanism of photocatalysis was also the main theme of this review article and how to overcome the recombination of photogenerated charges. By identifying these challenges, the review serves as a valuable resource for researchers, providing a roadmap for future endeavours to unlock the untapped capabilities of these materials. It serves as a beacon for environmental researchers, offering valuable insights into the pivotal role these materials can play in creating a more environmentally friendly and safe world. Ultimately, this review contributes significantly to the collective knowledge base and will prove instrumental for researchers and professionals dedicated to environmental protection and sustainable living. Graphical Abstract