Direct electron transfer from photosystem II to hematite in a hybrid photoelectrochemical cell

2015 ◽  
Vol 51 (95) ◽  
pp. 16952-16955 ◽  
Author(s):  
Wangyin Wang ◽  
Zhiliang Wang ◽  
Qingjun Zhu ◽  
Guangye Han ◽  
Chunmei Ding ◽  
...  

A hybrid photoanode integrating photosystem II with a hematite film is constructed for photoelectrochemical water oxidation.

2008 ◽  
Vol 105 (46) ◽  
pp. 17632-17635 ◽  
Author(s):  
Javier J. Concepcion ◽  
Jonah W. Jurss ◽  
Joseph L. Templeton ◽  
Thomas J. Meyer

Light-driven water oxidation occurs in oxygenic photosynthesis in photosystem II and provides redox equivalents directed to photosystem I, in which carbon dioxide is reduced. Water oxidation is also essential in artificial photosynthesis and solar fuel-forming reactions, such as water splitting into hydrogen and oxygen (2 H2O + 4 hν → O2 + 2 H2) or water reduction of CO2 to methanol (2 H2O + CO2 + 6 hν → CH3OH + 3/2 O2), or hydrocarbons, which could provide clean, renewable energy. The “blue ruthenium dimer,” cis,cis-[(bpy)2(H2O)RuIIIORuIII(OH2)(bpy)2]4+, was the first well characterized molecule to catalyze water oxidation. On the basis of recent insight into the mechanism, we have devised a strategy for enhancing catalytic rates by using kinetically facile electron-transfer mediators. Rate enhancements by factors of up to ≈30 have been obtained, and preliminary electrochemical experiments have demonstrated that mediator-assisted electrocatalytic water oxidation is also attainable.


2019 ◽  
Vol 23 (11n12) ◽  
pp. 1336-1345
Author(s):  
S. Jimena Mora ◽  
Daniel A. Heredia ◽  
Emmanuel Odella ◽  
Uma Vrudhula ◽  
Devens Gust ◽  
...  

Benzimidazole phenol-porphyrin dyads have been synthesized to study proton-coupled electron transfer (PCET) reactions induced by photoexcitation. High-potential porphyrins have been chosen to model P680, the photoactive chlorophyll cluster of photosynthetic photosystem II (PSII). They have either two or three pentafluorophenyl groups at the meso positions to impart the high redox potential. The benzimidazole phenol (BIP) moiety models the Tyr[Formula: see text]-His190 pair of PSII, which is a redox mediator that shuttles electrons from the water oxidation catalyst to P680[Formula: see text]. The dyads consisting of a porphyrin and an unsubstituted BIP are designed to study one-electron one-proton transfer (E1PT) processes upon excitation of the porphyrin. When the BIP moiety is substituted with proton-accepting groups such as imines, one-electron two-proton transfer (E2PT) processes are expected to take place upon oxidation of the phenol by the excited state of the porphyrin. The bis-pentafluorophenyl porphyrins linked to BIPs provide platforms for introducing a variety of electron-accepting moieties and/or anchoring groups to attach semiconductor nanoparticles to the macrocycle. The triads thus formed will serve to study the PCET process involving the BIPs when the oxidation of the phenol is achieved by the photochemically produced radical cation of the porphyrin.


2002 ◽  
Vol 357 (1426) ◽  
pp. 1471-1479 ◽  
Author(s):  
Martin Sjödin ◽  
Stenbjörn Styring ◽  
Björn Åkermark ◽  
Licheng Sun ◽  
Leif Hammarström

In the water–oxidizing reactions of photosystem II (PSII), a tyrosine residue plays a key part as an intermediate electron–transfer reactant between the primary donor chlorophylls (the pigment P 680 ) and the water–oxidizing Mn cluster. The tyrosine is deprotonated upon oxidation, and the coupling between the proton reaction and electron transfer is of great mechanistic importance for the understanding of the water–oxidation mechanism. Within a programme on artificial photosynthesis, we have made and studied the proton–coupled tyrosine oxidation in a model system and been able to draw mechanistic conclusions that we use to interpret the analogous reactions in PSII.


2020 ◽  
Vol 10 (21) ◽  
pp. 7344-7351
Author(s):  
Wenlong Guo ◽  
Ya Wang ◽  
Xin Lian ◽  
Yao Nie ◽  
Shijia Tian ◽  
...  

For CuWO4, oxygen vacancies can shorten the electron transfer time and boost the water oxidation kinetics, but they aggravate the charge recombination on the surface.


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