Preparation and Characterization of Metal-free graphitic Carbon Nitride Film Photocathodes for Light-induced Hydrogen Evolution

TL;DR

This study reports the successful preparation and characterization of metal-free graphitic carbon nitride films as photocathodes capable of light-induced hydrogen evolution, demonstrating their potential in solar fuel applications.

Contribution

It introduces a novel method to prepare g-C3N4 films on semiconductors and demonstrates their effectiveness for hydrogen evolution under visible light.

Findings

g-C3N4 films are highly porous with nanocrystalline structure

Photocathodes show hydrogen evolution under visible light

Surface analysis confirms chemical composition suitable for photoelectrochemical activity

Abstract

Very recently, it has been shown that an abundant material, polymeric carbon nitride, can produce hydrogen from water under visible-light irradiation in the presence of a sacrificial donor [1]. We will present here the preparation and characterization of graphitic carbon nitride (g-C3N4) films on semiconducting substrates by thermal condensation of dicyandiamide precursor under inert gas conditions. Structural and surface morphological studies of the carbon nitride films suggest a high porosity of g-C3N4 thin film consisting of a network of nanocrystallites. Photo-electrochemical investigations show upon cathodic polarization light-induced hydrogen evolution for a wide range of proton concentrations in the aqueous electrolyte. Additionally, Synchrotron radiation based photoelectron spectroscopy has been applied to study the surface/near-surface chemical composition of the utilized g-C3N4 film photocathodes. For the first time it is shown that g-C3N4 films can be successfully applied as photoelectrochemical material for light induced hydrogen evolution. [1]X. Wang, K. Maeda, A. Thomas, K. Takanabe, G. Xin, J. M. Carlsson, K. Domen, M. Antonietti, Nature Mat. 2009, 8, 76-80.