Catalytic Photothermal Hydrogenation of Carbon Dioxide to Liquid Fuels using Pt/GaN Prepared via Surface Organometallic Chemistry

Abstract Renewable liquid fuels are expected to play a crucial role in transitioning to a more sustainable future. Their synthesis via the hydrogenation of CO 2 using solar energy emerges as a promising technology, combining both the utilisation of a renewable primary energy source and the (re)utilisation of a major greenhouse gas. In this context, GaN has attracted a lot of attention in harnessing solar energy to drive chemical transformations. In this work, we study GaN by 1 H solid‐state NMR spectroscopy, revealing the presence of terminal Ga‐OH, bridging Ga‐NH‐Ga, as well as Ga‐OH‐Ga surface functional groups and combinations thereof. With this knowledge in hand, we make use of surface organometallic chemistry (SOMC) to prepare a Pt/GaN catalyst with highly dispersed Pt nanoparticles on GaN. Under photothermal conditions using visible light (>320 nm), the synthesised Pt/GaN promotes the hydrogenation of CO 2 to C 2+ products such as acetone, EtOH, i PrOH, and acetic acid in a batch reactor at 60 °C and 1 bar of pressure, while the pristine GaN counterpart only produces minor amounts of MeOH and acetone. Furthermore, a recycling test was performed to showcase the stability of the catalyst over multiple batch reaction cycles.