Photocatalytic Hydrogen Production from Noncovalent Biohybrid Photosystem I/Pt Nanoparticle Complexes

Abstract

A photocatalytic hydrogen-evolving system based on intermolecular electron transfer between native Photosystem I (PSI) and electrostatically associated Pt nanoparticles is reported. Using cytochrome c6 as the soluble mediator and ascorbate as the sacrificial electron donor, visible-light-induced H2 production occurs for PSI/Pt nanoparticle biohybrids at a rate of 244 μmol H2 (mg chlorophyll)−1 h−1 or 21 034 mol H2 (mole PSI)−1 h−1. These results demonstrate that highly efficient photocatalysis of H2 can be obtained for a self-assembled, noncovalent complex between PSI and Pt nanoparticles; a molecular wire between the terminal acceptor of PSI, the [4Fe−4S] cluster FB, and the nanoparticle is not required. EPR characterization of the electron-transfer reactions in PSI/Pt nanoparticle biohybrids shows blocked electron transfer to flavodoxin, the native acceptor protein of PSI, and presents evidence of low-temperature photogenerated electron transfer between PSI and the Pt nanoparticle. This work demonstrates a feasible strategy for linking molecular catalysts to PSI that takes advantage of electrostatic-directed assembly to mimic acceptor protein binding.

Photoelectrochemical Communication between Thylakoid Membranes and Gold Electrodes through Different Quinone Derivatives

“…Nature has optimized photosynthesis, its own solar energy-conversion system, to a finely tuned molecular mechanism. [1] Photosynthesis is the sustainable, efficient, and complex process that converts light energy into chemical energy. [2] Thylakoid membranes, photosynthetic subcellular organelles, are found in cyanobacteria and in plant chloroplasts.…”

“…[6][7][8][9][10] Isolated photosynthetic reaction centers, especially PS I, have been wired to electrodes to produce hydrogen as a feasible energy source. [1,[11][12][13] Isolated PS I has previously been wired to a gold electrode by using an osmium-containing redox polymer and methyl viologen as a final electron acceptor, which generated a photocurrent density of 29 mA cm À2 . [14] To take advantage of natural photosynthesis, several research groups have devoted their efforts on photobioelectrochemical systems that are based on chloroplasts, [15] thylakoid membranes, [16][17][18][19] photosynthetic reaction centers, [2,[20][21][22][23][24][25][26][27] and bacterial cells.…”

Integrated photosystem II-based photo-bioelectrochemical cells

“…Different bioelectrochemical devices that implement the RC, PSI and/or PSII as light harnessing components for the activation of PBFCs producing photocurrents [19][20][21][22] , or fuel products [23][24][25] have been proposed. These PBFCs require the immobilization and electrical contacting of the light harnessing components with the electrode supports to the extent that photo-induced electrontransfer processes occur between the photosynthetic RC, thus enabling the generation of photocurrents (or their use for the synthesis of fuel products).…”

Solar Photoelectrochemical Water Splitting with Bioconjugate and Bio-Hybrid Electrodes

“…The hybrid system evolves hydrogen signifi cantly in the order of 5,275 μmol of H 2 (μmol protein) −1 h −1 at pH 7 with methanol as sacrifi cial electron donor and at AM1.5 light [ 8 ]. Recently, hydrogen-evolving hybrid photocatalysts were fabricated by the noncovalent interaction of photosystem I with Pt nanoparticles [ 29 ]. In another case, a conjugate of photosystem I has been made with platinum catalyst.…”