Uppsala University, Sweden
Ashwin Kishore has his expertise in computation modeling of two dimensional materials for photocatalytic and photovoltaic applications. He is currently a postdoc in Department of Chemistry at Uppsala University, Sweden working on surface modification of two dimensional materials for CO2 reduction. His PhD work was on tailoring the properties of C2N monolayer for water splitting. He has demonstrated using density functional theory that the C2N monolayer could be a potential photocatalyst for water splitting and reported several ways to improve its efficiency. He has been invited to evaluate the project on developing photo-electrochemical cells based on C2N monolayer by a spin off company from Linkoping University, Sweden.
The direct splitting of water to produce hydrogen using semiconducting materials in the presence of sunlight plays a vital role in addressing the global energy demand and environmental related issues. It is to be noted that solar water splitting no doubt represents a promising and sustainable method for energy production. But its relatively low-energy conversion efficiency limits its practical applications. Hence, there is an urgent demand to search for potential photocatalytic materials with efficiency beyond current state of the art. Recently, experimentally synthesized nitrogenated holey graphene (C2N) have drawn great interest for wide variety of applications due to its excellent electronic and optical properties. We have studied its photocatalytic activity for water splitting and reported some of the promising ways to improve its efficiency further [1-3]. This talk mainly demonstrates the computational efforts on tailoring the electronic structure, band gap, and band edge positions of C2N monolayer for water splitting applications. We have demonstrated using hybrid density functional calculations that isoelectronic substitutions at both carbon and nitrogen sites in the C2N monolayer improve the photocatalytic water splitting activity significantly. I will discuss the influence of impurity adsorption such as hydrogen and halogen molecules on C2N monolayer for photocatalytic water splitting, especially how I2 molecule improves the photocatalytic water splitting activity. I will also present our on-going work on CdX-C2N (X=S,Se) heterostructures. Our results show that the proposed heterostructures are promising photocatalysts for water splitting. Overall, this talk aims to give a flavor on how computational methods helps to identify a potential photocatalyst for water splitting and also how one can tune its efficiency further by adopting various methods like isoelectronic ion substitution, surface adsorption, and heterostructure construction.