Ti cluster-alkylated hydrophobic MOFs for photocatalytic production of hydrogen peroxide in two-phase systems.

A hydrophobic MOF, OPA/MIL-125-NH2, whose Ti cluster was alkylated with octadecylphosphonic acid (OPA), was found to enhance photocatalytic H2O2 production in a two-phase system. Its activity exceeded that of linker-alkylated MIL-125-NH2. OPA/MIL-125-NH2 was modified on its outermost surface, which resulted in the activity enhancement while preserving the inner pores of the inherent MOF.

Two-Phase System Utilizing Hydrophobic Metal-Organic Frameworks (MOFs) for Photocatalytic Synthesis of Hydrogen Peroxide.

Much effort has been devoted to photocatalytic production of hydrogen peroxide (H2 O2 ) as an alternative to fossil fuels. From an economic point of view, reductive synthesis of H2 O2 from O2 coupled with the oxidative synthesis of value-added products is particularly interesting. We herein report application of MIL-125-NH2 , a photoactive metal-organic framework (MOF), to a benzylalcohol/water two-phase system that realized photocatalytic production and spontaneous separation of H2 O2 and benzaldehyde. Hydrophobization of the MOF enabled its separation from the aqueous phase. This resulted in enhanced photocatalytic efficiency and enabled application of various aqueous solutions including extremely low pH solution which is favorable for H2 O2 production but fatal to MOF structure. In addition, a highly concentrated H2 O2 solution was obtained by simply reducing the volume of the aqueous phase.

Photocatalytic production of hydrogen peroxide through selective two-electron reduction of dioxygen utilizing amine-functionalized MIL-125 deposited with nickel oxide nanoparticles.

Photocatalytic H2O2 production via two-electron reduction of O2 was realized by visible-light irradiation of a metal-organic framework, MIL-125-NH2, in the presence of TEOA and benzylalcohol. Deposition of NiO nanoparticles onto MIL-125-NH2 dramatically enhanced the catalytic activity. Further studies suggested that fast disproportionation of the O2˙- intermediate to H2O2 resulted in the enhancement.

Catalytic hydrogen production from paraformaldehyde and water using an organoiridium complex.

Paraformaldehyde was decomposed using an organoiridium complex (1, [Ir(III)(Cp*)(4-(1H-pyrazol-1-yl-κN(2))benzoic acid-κC(3))(H2O)]2SO4) as a catalyst in water to produce H2 and CO2 in a 2 : 1 molar ratio at room temperature. The catalytic cycle is composed of the reduction of 1 by paraformaldehyde under basic conditions to produce formic acid and the hydride complex, which reacts with protons to produce H2. Formic acid further decomposed to H2 and CO2 with 1.