MXene-bio composite coatings for advanced sustainable fire retardancy at surfaces and interfaces

Abstract MXenes, known for their unique properties and versatility, have garnered massive applications in fields such as energy storage, water purification, and fire-retardancy. However, while highly effective, MXenes raise significant concerns regarding toxicity, environmental impact, and synthesis methods, which often involve hazardous chemicals. In response, incorporating bio-based additives (derived from plant or animal sources) emerges as a promising strategy to enhance MXene effectiveness, mitigate toxicity, and promote sustainable practices. This review explores the synergistic potential of combining MXene with bio-derived materials, including plant-based additives like lignin, cellulose, and soy protein, and animal-based counterparts such as DNA, casein, and chitosan. These combinations have demonstrated significant improvements in flame retardancy, with peak heat release rate (PHRR) reductions of up to 83%, total heat release (THR) reductions of 69%, and total smoke release (TSR) reductions exceeding 85%. Additionally, MXene-bio composites have achieved limiting oxygen index (LOI) values surpassing 45%, highlighting their enhanced thermal stability and self-extinguishing properties. Beyond their fire-retardant benefits, these materials also contribute to a reduced environmental footprint by replacing synthetic additives with biodegradable and renewable components. Additionally, the review addresses critical challenges, such as developing scalable, eco-friendly synthesis methods and navigating regulatory requirements, aiming to provide a comprehensive perspective on advancing MXene-bio composites toward sustainable fire-retardant applications. Graphical abstract