Magnetic In–Pd catalysts for nitrate degradation†
Magnetic catalysts offer the possibility of rapidly eliminating nitrate oxyanions, a ubiquitous drinking water contaminant, without generating a secondary waste stream. Herein, we report the synthesis of a magnetically recoverable bimetallic Pd–In material that exhibits excellent chemical stability, reusability, and high nitrate removal efficiency. This four-component catalyst (Pd–In/nFe3O4@SiO2) contains nanocrystalline magnetite with a silica shell upon which indium-decorated palladium nanoparticles attach. The SiO2 shell slowed down iron leaching from Fe3O4 and the bimetallic nano-domains showed nitrate reduction activity in deionized water without obvious deactivation through multiple recovery and reuse cycles. This magnetically responsive, reusable catalyst, which retained activity in simulated drinking water, can serve as a design basis for materials to degrade other oxyanion water contaminants.