By using non-equilibrium Green's functions in combination with the density-functional theory, we study the
effect of zigzag graphene nanoribbons with edge hydrogenation and oxidation on transport properties. We find that for the
ferromagnetic (FM) configuration the ZGNRs with CH2-CH group exhibit spin diode effect in which only one spin can
occur under positive bias while the other spin occurs under negative bias. In the antiferromagnetic (AF) state the
symmetric ZGNRs with CH2-CH group show the spin filter effect within some specific energy windows. However, the
asymmetric ZGNRs with CH2 -CH group do not show such a spin filter effect. We also find that the symmetric and
asymmetric ZGNRs with C2O-CH group in AF configurations show similar transport behaviors at the Fermi level. Such
ZGNRs might be exploited in spintronic nanodevices.