A Heterogeneous Carbon Nitride-Nickel Photocatalyst for Efficient Low-Temperature CO2 Methanation

The Sabatier reaction, i.e., the hydrogenation of CO2 to methane (CH4) using hydrogen (H-2), constitutes a potentially scalable method to store energy in a product with a high energy density. However, up to today, this reaction has been mainly thermally driven and conducted at high temperatures (typically 400-600 degrees C). Using light as a renewable energy source will allow for a more sustainable process by lowering the reaction temperature. Here, it is demonstrated that Ni nanoparticles support on graphitic carbon nitride (g-CN) are a highly efficient and stable photocatalyst for the gas-phase CO2 methanation at low temperature (150 degrees C). Detailed mechanistic studies reveal a very low activation energy for the reaction and high activity under visible light, leading to a remarkable and continuous CH4 production of 28 mu mol g(-1) h(-1) of CH4 for 24 h.