Photocatalytic Aqueous Reforming of Methyl Formate

Green hydrogen is critical to establish a sustainable energy future as it offers a clean, renewable, and a versatile alternative for decarbonizing industries, transportation, and power generation. However, the limitations of current methods significantly restrict the scope and hinder many of the envisioned applications. This study aims to report on the first example of a 3d-metal-based (Cu) heterogeneous photocatalytic system to produce green hydrogen via dehydrogenation of methyl formate (MF), a reaction previously known to require 4d/5d transition metals. Employing a Cu-based atomically dispersed heterogeneous photocatalyst supported on aryl-amino-substituted graphitic carbon nitride (d-gC₃N₄), the protocol offers numerous key advantages, including the recyclability of the photocatalyst for >10 cycles without significant activity loss, sustained hydrogen production (>15 days!) with high hydrogen yield (19.8 mmol g_cat ^-1) and negligible CO emission, following an operationally simple, sustainable, and efficient catalytic pathway. Furthermore, the photocatalyst is characterized (using HAADF-STEM, SS-NMR, XAS, EPR, and XPS), all of which clearly demonstrated the presence of single atomic Cu-site. Additionally, comprehensive mechanistic investigations together with DFT calculations allow for a thorough mechanistic rationale for this reaction. It is strongly believed that this atomically dispersed heterogeneous photocatalytic approach will open new avenues for establishing liquid organic hydrogen career (LOHC) technologies.