Effect of Cu(II) on the formation, morphology and molecular adsorption properties of α-FeOOH rust particles prepared from acidic Fe(III) solutions

► Artificial α-FeOOH rust particles were prepared from acidic aqueous Fe(NO3)3 solution in the presence of Cu(NO3)2. ► Formation of steel rust particles was accelerated by addition of Cu(II). ► Adding Cu(II) suppressed the growth of α-FeOOH particles and formed the nano-sized ferrihydrite particles. ► The adsorption affinity to corrosive gasses such as H2O, CO2 and SO2 was lowered by doping Cu(II).