Carbon nitride-based materials and deposition methods for water-splitting photoelectrochemical cells

Graphitic carbon nitride materials (CNs) have emerged as suitable photo- and heterogeneous- catalysts for various reactions thanks to their tunable band gap, suitable energy-band position, high stability under harsh chemical conditions, and low cost. However, the utilization of CN in photoelectrochemical (PEC) and other photoelectronic devices is still at an early stage owing to the difficulties in depositing high-quality and homogenous CN layer on substrates, its wide band gap, poor charge-separation efficiency, and low electronic conductivity.¹

We show synthetic pathways for the preparation of various structures of CN on substrates developed in our group, and their underlying photophysical properties and current photoelectrochemical performance. These include a novel doctor-blading of supramolecular assembly paste² (possibly combined with reduced graphene oxide),³ and closely-packed CN film using crystallization of monomers.⁴ The main challenges for CN incorporation into PEC cell are described, together with possible routes to overcome the standing limitations toward the integration of CN materials in PEC and other photoelectronic devices.¹

(1) Volokh, M.; Peng, G.; Barrio, J.; Shalom, M. Carbon Nitride Materials for Water Splitting Photoelectrochemical Cells. Angew. Chem. Int. Ed.2018. DOI 10.1002/anie.201806514

(2) Peng, G.; Xing, L.; Barrio, J.; Volokh, M.; Shalom, M. A General Synthesis of Porous Carbon Nitride Films with Tunable Surface Area and Photophysical Properties. Angew. Chem. Int. Ed.2018, 57(5), 1186–1192.

(3) Peng, G.; Volokh, M.; Tzadikov, J.; Sun, J.; Shalom, M. Carbon Nitride/Reduced Graphene Oxide Film with Enhanced Electron Diffusion Length: An Efficient Photo-Electrochemical Cell for Hydrogen Generation. Adv. Energy Mater.2018, 8(23), 1800566.

(4) Peng, G.; Albero, J.; Garcia, H.; Shalom, M. A Water-Splitting Carbon Nitride Photoelectrochemical Cell with Efficient Charge Separation and Remarkably Low Onset Potential. Angew. Chem. Int. Ed.2018, 57(48), 15807–15811.