Multi-Component Metal-Organic Frameworks Significantly Boost Visible-Light-Driven Hydrogen Production Coupled with Selective Organic Oxidation.

Abstract

Visible-light-driven hydrogen production coupled with selective organic oxidation has attracted increasing attention, as it not only provides clean and renewable energy, but also utilizes the other half reaction to achieve some value-added organic chemicals. Metal-organic frameworks based on metal clusters and organic ligands self-assembly give a perspective on the formation of multifunctional heterogeneous photocatalyst to significantly boost visible-light photocatalytic activities under mild conditions. By incorporating two types of photoactive units, tricarboxytriphenylamine (H3 TCA) and tris(4-(pyridinyl)phenyl)amine (NPy3 ), into a single metal-organic frameworks, a multi-component MOF Co-MIX was obtained. With the redox active metal centers enabling the photoexcitation reduction of protons into hydrogen and the photogenerated holes promoting considerable oxidation of substrates, the resulting Co-MIX exhibits high catalytic activity for the photocatalytic hydrogen production coupled with selective oxidation of benzylamine or 1,2,3,4-tetrahydroisoquinoline. Importantly, the photocatalytic experiments of single-component Co-TCA and Co-NPy3 verified the positive synergistic effects on stability and photocatalytic ability of the two ligands (H3 TCA and NPy3 ) in one single MOF, revealing that the multi-component strategy is very important for the efficient charge separation and excellent photocatalytic activity of the catalyst.