Conjugates of reduced phosphorus-nitrogen co-doped graphene oxide nanosheets (rPNDGONS), reduced phosphorus doped graphene oxide nanosheets (rPDGONS), reduced nitrogen doped graphene oxide nanosheets (rNDGONS), reduced pyrolised graphene oxide nanosheets (rpyGONS) with nanosized cobalt (II) phthalocyanine (CoPcNP) or cobalt tetra amino phenoxy phthalocyanine (CoTAPhPcNP) were characterised and tested for their electrocatalytic behaviour towards the detection of hydrogen peroxide. Cyclic and linear scan voltammetries, and chronoamperometry were used to evaluate the electrocatalytic nature of the designed probes. For hydrogen peroxide detection, CoPcNP-rPNDGONS-GCE oxidation gave sensitivity of 12.00 mA/M, limit of detection of 4.48 nM, a rate constant of 2.66 x 10(5) M (1) s (1), adsorption equilibrium constant of 3.7 x 10(2) M (1) and Gibbs free energy -14.84 kJmol (1). The lowest detection limit was obtained for CoTAPhPcNP-rPNDGONS-GCE at 1.21 nM. (C) 2016 Elsevier Ltd. All rights reserved.