Formation of carbon nitride films using electrophoretic deposition of supramolecular assemblies for enhanced photoelectrochemical cell performance

Carbon nitride-based materials (CN) have earned great interest as robust and cheap metal-free semiconductors. CN materials have been used as photo-catalysts due to their tunable band gap, chemical stability and desirable band positions for various reactions including water-splitting –hydrogen and oxygen evolution reactions (HER and OER, respectively). However, the exfoliation of CN materials in photoelectronic devices such as photoelectrochemical cells is still limited due to the difficulties to growth CN layer on substrates. For example, in order to utilize the CN materials in photoelectrochemical cells (PEC) for water splitting, the CN materials should be deposited first on a conductive substrate. Most of the recent progress in the incorporation of CN in PECs focuses on the deposition of prepared CN materials, which makes the control over the prepared electrode’s properties more challenging.

Electrophoretic deposition (EPD) is a proven facile method of deposition on conductive substrates. The simplicity of this method stems from the ability to control film thickness by altering the parameters of deposition (e.g., applied electrical field) and the parameters of the solution such as concentration and solvent. EPD has been used previously to deposit prepared CN powders,¹ but here we report for the first time a method to deposit supramolecular assemblies directly on conductive substrates in order to convert them into CN films using a thermal treatment. We demonstrate how altering different supramolecular entities allows controlling the final properties of CN-based photoelectrodes such as morphology, porosity, specific surface area, conductivity, and optical absorbance.

1 J. Xu and M. Shalom, ACS Appl. Mater. Interfaces, 2016, 8, 13058–13063.