Visible-Light-Promoted Photocatalytic Hydrogen Production by Using an Amino-Functionalized Ti(IV) Metal–Organic Framework

Abstract

The present article describes the hydrogen production from an aqueous medium over amino-functionalized Ti(IV) metal–organic framework (Ti-MOF-NH2) under visible-light irradiation. Ti-MOF-NH2, which employs 2-amino-benzenedicarboxylic acid as an organic linker, has been synthesized by a facile solvothermal method. Pt nanoparticles as cocatalysts are then deposited onto Ti-MOF-NH2 via a photodeposition process (Pt/Ti-MOF-NH2). The XRD and N2 adsorption measurements reveal the successful formation of a MOF framework structure and its remaining structure after deposition of Pt nanoparticles. The observable visible-light absorption up to ∼500 nm can be seen in the DRUV–vis spectrum of Ti-MOF-NH2, which is associated with the chromophore in the organic linker. Ti-MOF-NH2 and Pt/Ti-MOF-NH2 exhibit efficient photocatalytic activities for hydrogen production from an aqueous solution containing triethanolamine as a sacrificial electron donor under visible-light irradiation. The longest wavelength available for the reaction is 500 nm. The results obtained from wavelength-dependent photocatalytic tests and photocurrent measurements as well as in situ ESR measurements demonstrate that the reaction proceeds through the light absorption by its organic linker and the following electron transfer to the catalytically active titanium-oxo cluster.

Co@NH2-MIL-125(Ti): cobaloxime-derived metal–organic framework-based composite for light-driven H2 production

“…It is noteworthy that NH 2 -MIL-125(Ti) has been used for photocatalytic hydrogen production, both in the absence and presence of Pt-nanoparticles, 24 suggesting that the reduction potential of the excited states in the MOF is sufficient to drive proton reduction in line with computational predictions. 47 We chose the oxygen-tolerant and…”

“…24,25 The small downeld feature at g ¼ 2.01 is associated with the spatially conned amino-groups in the MOF. 26,41 The EPR spectrum of Co@MOF in the dark (Fig.…”

Exploration of Zr–Metal–Organic Framework as Efficient Photocatalyst for Hydrogen Production

“…Horiuchi et al synthesized the amino-functionalized Ti-MOF-NH 2 , which exhibited efficient photocatalysis for hydrogen production reaction with triethanolamine (TEOA) as a sacrificial electron donor under visible-light irradiation condition [40]. Jiang et al structured electron trap states in a metal-organic framework to enhance separation of electron-hole, which applied visible-light photoreduction of CO 2 [41].…”

Photochemical Hydrogen Production with Metal–Organic Frameworks

“…Two years later, Matsuoka and coworkers picked up on this idea and reported a Ti-based MOF that contains aminoterephthalic acid linkers with a structure similar to that of MIL-125(Ti) [54]. They reasoned that the more positive conduction band of the titanium-oxo cluster compared to zirconium could be favorable for driving visible light photocatalysis.…”

“…4 Photochemical hydrogen production making use of photosensitizing framework. Pt-nanoparticles [54] or cobaloxime [55] were used as catalysts observed with TEA, EDTA or methanol. The authors attributed the need of TEOA to the weak oxidation power of the organic linker.…”