Chemically Immobilized Triazine Based Cu II S 3 C 3 N 3 Metallopolymer on Copper as a Photocathode for Photoelectrochemical Hydrogen Evolution

Abstract

? 2016 The Electrochemical Society.Visible-light active metallopolymeric network of triazine trithiolate containing Cu2+ (CuTCA) is chemically coordinated to the Cu electrode has been grown by electrochemical and chemical methods. The metallopolymeric thin films growth depend on the concentration of triazine trithiol (TCA), applied anodic potential and the duration of polymerization. XPS and Grazing angle FT-IR investigations reveal that TCA is chemically coordinated to Cu electrode through Cu-S linkage and it forms a metallopolymeric network (CuTCA) structure on the electrode surface through -S-CuII-S-linkage. The surface morphology of thin film exhibits nanoflake like features. UV-Visible spectra of these thin films display the absorption maxima mainly in the visible region (?max - 620 nm) and this is significantly distinct to the nonmetallated C3N3S3 polymer. Photoelectrochemical studies of these p-type CuTCA photocathodes show a better photocurrent response of nearly 11-15 ?A cm-2. In comparison to bare Cu electrode, the CuTCA coated Cu electrodes display a three-fold increase in current density and nearly a 400 mV positive potential shift for hydrogen evolution in acidic medium. Potentiostatic impedance measurements of CuTCA coated electrodes show an excellent reduction in the charge transfer resistance and long-term stability for hydrogen evolution.