Grave-to-cradle upcycling of Ni from electroplating wastewater to photothermal CO₂ catalysis

Treating hazardous waste Ni from the electroplating industry is mandated world-wide, is exceptionally expensive, and carries a very high CO2 footprint. Rather than regarding Ni as a disposable waste, the chemicals and petrochemicals industries could instead consider it a huge resource. In the work described herein, we present a strategy for upcycling waste Ni from electroplating wastewater into a photothermal catalyst for converting CO2 to CO. Specifically, magnetic nanoparticles encapsulated in amine functionalized porous SiO2, is demonstrated to efficiently scavenge Ni from electroplating wastewater for utilization in photothermal CO2 catalysis. The core-shell catalyst architecture produces CO at a rate of 1.9 molNi−1 h−1 (44.1 mmol gcat h−1), a selectivity close to 100%, and notable long-term stability. This strategy of upcycling metal waste into functional, catalytic materials offers a multi-pronged approach for clean and renewable energy technologies.