Upcycling electroplating sludge into bioengineering-enabled highly stable dual-site Fe-Ni₂P@C electrocatalysts for efficient oxygen evolution

The advancement of bimetallic catalysts holds significant promise for the innovation of oxygen evolution reaction (OER) catalysts. Drawing from adsorbate evolution mechanism (AEM) and lattice oxygen oxidation mechanism (LOM), the incorporation of dual active sites has the potential to foster novel OER pathways, such as the coupled oxygen evolution mechanism (COM), which can surpass the limitations of OER and elevate catalytic performance. In this study, uniformly distributed Fe/Ni dual-site Fe-Ni₂P@C electrocatalysts are crafted by upcycling metals in electroplating sludge via an eco-friendly and sustainable microbial engineering technique. Our findings indicate that a substantial number of defects emerge at the Ni₂P crystal during the OER process, laying the groundwork for lattice oxygen involvement. Moreover, the displacement of Ni/Fe in the crystal lattice intensifies the asymmetry of the electronic structure at the metal active sites, facilitating the deprotonation process. This research introduces an innovative paradigm for the synthesis of effective and robust transition metal-based OER catalysts, with implications for sustainable energy generation technologies.