Upcycling Nickel Ions into self-supported Electrocatalyst by using ZIF-8/ Bacterial cellulose adsorbent

Upcycling valuable metals from wastewater promises addressing the metal resource recycling and water pollution control issues simultaneously. In particular, upcycling Nickel (Ni) ions into electrocatalytic material has been proven a feasible route, but the current methods are still restricted by the complicated, environmentally-aggressive operation. Herein, we propose a low-cost, 3D-structured adsorbent, constructed by in-situ growing ZIF-8 on network-structured bacterial cellulose, for efficient Ni capture. It exhibits superior stability and 7.3-times higher Ni adsorption kinetics than the ZIF-8 alone. Importantly, the Ni-enriched adsorbent, after treatment of Ni-containing electroplating wastewater, could be pyrolytically converted into an efficient self-supported electrocatalyst for oxygen evolution reaction (OER), showing comparable OER activity to the state-of-the-art Ni-based electrode. This work provides a sustainable, facile route for Ni upcycling into selfsupported electrode, which may be extended to recovery of various valuable metals from waste streams.