Mixed self-assembled monolayers of Co-porphyrin and n-alkane phosphonates on gold

► n-alkane-PO3H2 adsorb spontaneously on Au with coverages similar to thiol derivatives. ► Functionalization of Au by pure and mixed Co-porphyrin: alkane-PO3H2 demonstrated. ► Mixed monolayers deposition enable Co-porphyrin surface dilution with n-alkanes-PO3H2. ► Immobilized Co-porphyrin-PO3H2 exhibit electrochemical activity in organic medium. ► Pure and mixed Co-porphyrin monolayers are electrocatalytic towards O2 reduction.