Waste-derived electrocatalysts for electrochemical CO₂ reduction: A circular approach to carbon valorization

Transforming waste into opportunity is central to climate resilience and sustainable development. This review explores the cutting-edge use of waste-derived electrocatalysts for electrochemical CO₂ reduction (eCO₂RR) to convert CO₂ into valuable chemicals and fuels. The broader implementation of eCO₂RR hinges on developing cost-effective, high-performance electrocatalysts. Over 45 waste streams encompassing electronic waste, biomass, industrial byproducts, and plastics have been examined for their potential to be transformed into functional catalysts through pyrolysis, hydrothermal synthesis, chemical leaching, mechanical separation, and hybrid recycling. These materials leverage the inherent metal content, heteroatom functionalities, and carbon-rich structures found in waste, achieving Faradaic efficiencies of up to 98 % for products including CO, formate, and methanol. The relationship between structural features and catalytic performance was emphasized, particularly how surface area tuning, nitrogen doping, and active site engineering enhance selectivity and reaction kinetics. By redefining waste as a valuable feedstock for carbon conversion, this review provides a comprehensive framework for advancing low-carbon chemical manufacturing and accelerating the transition toward a circular carbon economy.