External magnetic field was applied during syntheses of α-Fe2O3 nanocatalyst. α-Fe2O3 nanocatalyst with enhanced magnetic properties was synthesized. Effect of magnetic properties and morphology of α-Fe2O3 on ammonia yield was tested. α-Fe2O3 nanowires with improved saturation magnetization created high ammonia yield. A maximum green ammonia yield of 24.174 × 10−3 mol h−1 g cat−1 was produced.