Suitability of FeCo/GC@MSS for use in the reaction system. (a) Field-dependent magnetization hysteresis of FeCo/GC@MSS at 300 K. (b) Nitrogen adsorption/desorption isotherm of MSS and FeCo/GC@MSS. (c) Photographs of 35% HCl solutions of (i, ii) FeCo/GC@MSS stored over a monitoring period of 2 months in air (i) and water (ii) and (iii) as-prepared FeCo@MSS. (d) A photograph of recycled PMA@FeCo/GC@MSS in acetonitrile in the presence of an external magnet. (e) TEM image of the PMA@FeCo/GC@MSS after the five sequential catalytic cycles.