Active site imprinting on Ti oxocluster metal-organic framework for the photocatalytic hydrogen release from formic acid

On-board hydrogen release from liquid organic carriers is a process that can make feasible the use of H2 as transportation fuel. Formic acid is considered as one of the most convenient liquid hydrogen organic carriers, since it can be easily obtained from CO2, it is water soluble and it makes unnecessary to recover the H2-depleted byproducts. Compared to the more conventional thermal catalytic decomposition of formic acid, the use of light in combination with a photocatalyst has been much less explored. Herein, we report a new paradigm in MOF photocatalysis that is the use of a microporous titanium oxocluster based metal-organic framework (Ti-MOF) endowed by formate-imprinted active sites, namely MIP-177_LT (MIP stands for Materials from Institute of Porous Materials of Paris, LT for Low Temperature), as a highly efficient photocatalyst for H2 release from formic acid without the need to neutralize acidity or the use sacrificial agents or noble metals. Noteworthy, a quantum efficiency of 22 % has been determined for the photocatalytic H2 release that is highly remarkable for a non-toxic noble metal-free photocatalyst.