▎ 摘　　要

Our ecosystem is endangered by an increasing demand for re-sources, emission of pollutants, and wastes generated from indus-trial processes. Herein, we propose a sustainable upcycling strategy to tackle excessive carbon dioxide emissions and water quality is-sues synergistically. The crux of the strategy is to use seafood waste, easily converted to chitosan, to chelate heavy metals in contami-nated water and produce metal-doped graphene composites. Gra-phene composites are prepared by scalable one-step laser scribing with controllable metal ion and nitrogen sites. The catalysts enable the efficient electroreduction of carbon dioxide to carbon products with over 80% Faradaic efficiency at 100 mA cm -2 in a flow cell reactor and can also catalyze the degradation of organic micropollu-tants. A prospective life-cycle assessment demonstrates a lower global warming potential, compared with conventional systems, for this system being used to produce formic acid and olefins in the future. Our sustainable upcycling strategy is expected to inspire practical techniques for producing green chemicals and clean water.