Catalytic Photothermal Hydrogenation of Carbon Dioxide to Liquid Fuels using Pt/GaN prepared via SOMC

Renewable liquid fuels are expected to play a crucial role in transitioning to a more sustainable future. Their synthesis via the hydrogenation of CO2 using solar energy emerges as a promising technology, that combines both the use of a renewable primary energy source and the (re)utilization 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 1H 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 synthesized Pt/GaN promotes the hydrogenation of CO2 to C2+ products such as acetone, EtOH, iPrOH, 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.