Visible-Light-Driven Photoproduction of Hydrogen Using Rhodium Catalysts and Platinum Nanoparticles with Formate

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• 作者：Soojin Kim ; Ga Ye Lee ; Jin-Ook Baeg ; Youngmee Kim ; Sung-Jin Kim ; Jinheung Kim
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：November 13, 2014
• 年：2014
• 卷：118
• 期：45
• 页码：25844-25852
• 全文大小：372K
• ISSN：1932-7455

文摘

Photochemical hydrogen production is carried out using molecular Rh complexes and sodium formate in the presence of platinum nanoparticles (PtNPs) in aqueous buffer solution. Visible-light-driven photocatalytic reactions for hydrogen production with and without nicotinamide adenine dinucleotide (NAD⁺) follow two different pathways. Complex [Cp*Rh(bpy)(OH₂)]²⁺ selectively reduces NAD⁺ to generate NADH using formate as a proton and electron donor and the chemically generated NADH is sequentially used by PtNPs upon photoactivation of eosin Y to produce hydrogen. However, hydrogen is also produced in photoreactions of the Rh catalyst and PtNPs with formate in the absence of NAD⁺ and eosin Y. The second pathway for hydrogen production was performed under the conditions without NAD⁺ and eosin Y and derived from a direct electron transfer from in situ generated rhodium(III)-hydride species to photoexcited PtNPs. The direct electron transfer from the rhodium-hydride species to visible-light-driven PtNPs was first observed in this study. These two pathways for hydrogen production showed different rate-limiting steps based on a Hammett plot using Rh catalysts containing electron-donating and electron-withdrawing groups. Kinetic isotope effects as well as Hammett plot supported the rate-limiting step of the NADH generation for the first pathway of hydrogen production and the Rh鈥揌 formation for the second pathway.