Metal Phthalocyanine Sensitized Photoelectrochemical Cell Assembling with Azide-Functionalized Reduced Graphene and Quaternary Metal Chalcogenide Composites

Abstract

Here, photoelectrodes of photoelectrochemical (PEC) cells consisting of azide functionalized reduced graphene oxide (GO-N3) and quaternary metal chalcogenide (CdZnNiSSe) composites sensitized with metal phthalocyanines (MPc, M: Co, Zn, Ti) are developed and then tested in hydrogen evolution reaction (HER). CdZnNiSSe/RGO-N3 composite is deposited on an indium tin oxide (ITO) electrode through a facile electrodeposition technique and ITO/CdZnNiSSe/RGO-N3 photoelectrode is constructed. Then, MPcs bearing terminal alkyne groups are connected to RGO-N3 via the copper(I)-catalyzed azide-alkyne cycloaddition (click chemistry) technique to produce ITO/CdZnNiSSe/RGO-N3-MPc structures. Decoration of ITO/CdZnNiSSe/RGO-N3 with MPcs is proposed to improve the charge transfer capability of the photoelectrode due to wide light absorption of MPcs from UV toward the IR region of the light spectrum. PECHER responses indicate that among the photoanodes bearing ZnPc, CoPc, and TiOPc, ITO/CdZnNiSSe/RGO-N3-ZnPc electrode exhibits the highest PECHER performance owing to the suitability of band structure of ZnPc. Sensitizing ITO/CdZnNiSSe/RGO-N3 with ZnPc increases the photocurrent density from 5.0 to 7.3 mA cm-2 at 0.8 V vs. RHE and the applied bias photon to current efficiency (ABPE) enhances from 3.18 % to 3.87 %. This study provides a new approach for increasing the performance of photoanodes via sensitization with MPcs in photoelectrochemical hydrogen evolution processes for future applications. Novel photoelectrodes are constructed with the electrodepositing of the azide functionalized reduced graphene oxide (GO-N3) and quaternary metal chalcogenide (CdZnNiSSe) composites which are then sensitized with metal phthalocyanines with the click chemistry reaction. The constructed ITO/CdZnNiSSe/RGO-N3-ZnPc electrode exhibits 7.3 mA cm-2 photocurrent and 3.87 % of applied bias photon to current efficiency in the photoelectrochemical hydrogen evolution reaction. image