Behzad Rezaei, Ahmad Reza Taghipour Jahromi, Ali Asghar Ensafi

a b s t r a c t
In this work, the porous spinel-type of magnetic iron-manganese oxide nanocubes with a hollow
structure deposited on the reduced graphene oxide nanoflakes (PMFMO@RGONF nanocomposite) is
synthesized and examined as a non-noble electrocatalyst for hydrogen evolution reaction (HER) and
oxygen reduction reaction (ORR). The Tafel slope of PMFMO@RGONF nanocomposite is about 107mV
dec
1 in the 0.50 mol L
1 H2SO4 solution and suggests the VolmereHeyrovsky mechanism for HER. The
results show that this electrocatalyst has an excellent stability (at least 10000 cycles) in the sulfuric acid
solution. Hence, The LSV curve shows that the Pt(20%)/C has a better onset-potential than present
electrocatalyst for HER but PMFMO@RGONF nanocomposite produces current density (j) of 300mA cm
2
at overpotential (ɳ) of
721mV (ɳ300¼
721 mV(vs. Ag/AgCl)) which is smaller than Pt(20%)/C
(ɳ300¼
802 mV). The PMFMO@RGONF nanocomposite as an electrocatalyst follows four electrons
mechanism for ORR in 0.10 mol L
1 KOH. As an important result, after addition of methanol into the
electrolyte, this electrocatalyst is stable for a long time (at least 10000s) while the catalytic activity of Pt
(20%)/C is quickly lost in the presence of methanol.

Magnetic iron-manganese oxide nanocubes, Hollow structure, Reduced graphene oxide nanoflakes
Hydrogen evolution reaction, Oxygen reduction reaction