Abstract Voltammetry of immobilised microcrystalline perovskites La(Ni,Cr)O3 and La(Ni,Fe)O3 revealed that these oxides yield three types of reactions in acidic aqueous solutions (0.1M HClO4): irreversible oxidative dissolution of Cr-rich oxides, irreversible reductive dissolution of Fe-rich oxides, and a quasi-reversible reaction most likely related to alteration of the valencies of Cr, Fe and/or Ni in the solid state. The samples of La(Cr1xNix)O3 with x=0.3 and 0.5 especially showed limited cycling stability that is particularly surprising in the very strongly acidic solution.