Effect of detonation nanodiamonds on the electrocatalytic activity of asymmetric cobalt phthalocyanine: Covalent versus non-covalent linking

We report on the effect of detonation nanodiamonds (DNDs) on electrocatalytic properties of an asymmetrically substituted cobalt phthalocyanine (CoPc). The incorporation of DNDs onto cobalt phthalocyanine enhances its electrochemical behaviour. An asymmetrical CoPc alone, when π-π stacked (CoPc-DNDs(ππ)) or covalently linked (CoPc@DNDs) to DNDs is used to modify a glassy carbon electrode (GCE) for the electrocatalytic detection of hydrazine. In addition, the GCE was modified by sequentially adding CoPc and DNDs onto its surface, represented as GCE/CoPc-DNDs(seq) when CoPc is placed before DNDs on the electrode and GCE/DNDs-CoPc(seq) when DNDs are placed before CoPc, where seq represents sequential. The obtained catalytic rate for the detection of hydrazine on GCE/CoPc@DNDs was 9.3×10⁴ M⁻¹.s⁻¹ with a limit of detection as 0.33 μM. GCE/CoPc@DNDs gave better electrocatalytic activities when compared to its counterparts.