Polymeric phthalocyanine sheets as electrocatalytic electrodes for water-oxidation

Abstract

Polymeric copper and cobalt phthalocyanine (Cu-pPc and Co-pPc) were prepared as thin films on fluorine-doped tin oxide (FTO) glass from evaporated metal films via a chemical vapor deposition (CVD) process with 1,2,4,5-tetracyanobenzene (TCB). The films were characterized by optical absorption spectroscopy in transmission and by X-ray photoelectron spectroscopy. Different oxidation states of the metal atoms were detected indicating different chemical environments. Reversible electrochemical reduction of Cu-pPc and Co-pPc was observed and monitored by cyclic voltammetry and spectroelectrochemical investigations. Cyclic voltammetry and chronoamperometry in the positive voltage range led to anodic currents in the oxygen evolution reaction that could be performed at stable current densities and showed a remarkable efficiency in particular for electrodes of Co-pPc in this reaction, attractive for the conversion of electrical energy into chemical energy.