Mechanism of photocatalytic conversion of methane to ethane on PdCu/TiO 2 photocatalyst Natalia Martsinovich University of Sheffield, UK Methane is one of the most promising future energy sources and chemical feedstocks. However, due to the inert nature of methane, the activation energy for its chemical conversion is high and requires harsh reaction conditions, such as high temperatures or strong oxidants, making the process environmentally unfriendly and too costly for commercial applications. Photocatalysis, which harnesses sunlight to drive chemical reactions, can offer a solution, using a combination of photocatalyst and co-catalyst to lower the activation barrier for C-H bond breaking to convert methane into reactive intermediates and ultimately into various value-added chemicals. Our experimental collaborators produced an efficient, stable and selective photocatalyst for oxidative coupling of methane to form ethane at room temperature, by depositing PdCu alloy nanoparticles on TiO 2 (manuscript under review). In this presentation, I will describe our theoretical investigation of the mechanism of methane conversion and the role of the PdCu alloy co-catalyst in the photocatalytic process. Density functional theory modelling revealed that the nanoalloy worked as a hole acceptor and promotes the separation of photogenerated charges. Calculations also showed that methane adsorbed more strongly on Pd and on the PdCu alloy than on TiO 2 ; moreover, the activation energy of C-H bond breaking, the key process in the conversion of methane, was significantly lower for methane adsorbed on the metal co-catalyst compared to methane on TiO 2 . Thus, the PdCu co-catalyst is essential for the efficient operation of the TiO 2 photocatalyst for methane conversion.
USC02
© The Author(s), 2023
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