A First-Principles High-Throughput Search for Layered Sulfides for CO2 Reduction Photocatalysis*

Artificial photosynthesis presents a promising opportunity to extract CO2 from the atmosphere and produce useful chemical fuels. While a wealth of water splitting photoanodes have been identified, efficient CO2 reduction calls for the discovery of new photocatalysts. In this work, we develop a high-throughput screening workflow using first-principles density functional theory (DFT) with van der Waals corrections to discover new CO2 reduction photocatalysts. The high valence bands, and hence high conduction bands, observed in low-band gap sulfides show promise for meeting the high redox potentials of CO2 reduction. We draw on the success of MoS2 as a CO2 reduction photocatalyst to motivate a search for layered sulfides with similar electronic, structural, and aqueous stability properties. With this workflow we analyze thousands of metal-sulfide compounds from the Materials Project database. We identify promising layered sulfides with DFT band gaps between 0-3 eV, minimal Pourbaix thermodynamic instability under CO2 reduction conditions and suitable band edge alignment to CO2 redox potentials.