Enhanced Photogenerated Electron Transfer in a Semiartificial Photosynthesis System Based on Highly Dispersed Titanium Oxide Nanoparticles

Xiaoqin Pan; Dongna Li; Yueping Fang; Zhihao Liang; Haoran Zhang; Jin Zhong Zhang; Bingfu Lei; Shiwei Song

doi:10.1021/acs.jpclett.9b03740

Enhanced Photogenerated Electron Transfer in a Semiartificial Photosynthesis System Based on Highly Dispersed Titanium Oxide Nanoparticles

J Phys Chem Lett. 2020 Mar 5;11(5):1822-1827. doi: 10.1021/acs.jpclett.9b03740. Epub 2020 Feb 20.

Authors

Xiaoqin Pan^{1

2}, Dongna Li², Yueping Fang², Zhihao Liang¹, Haoran Zhang^{2

3}, Jin Zhong Zhang⁴, Bingfu Lei^{1

2

3}, Shiwei Song¹

Affiliations

¹ College of Horticulture, South China Agricultural University, Guangzhou 510642, P.R. China.
² Guangdong Provincial Engineering Technology Research Center for Optical Agriculture, College of Materials and Energy, South China Agricultural University, Guangzhou 510642, P.R. China.
³ Guangdong Laboratory of Lingnan Modern Agriculture, Guangzhou 510642, P.R. China.
⁴ Department of Chemistry & Biochemistry, University of California, Santa Cruz, California 94720, United States.

PMID: 31995377
DOI: 10.1021/acs.jpclett.9b03740

Abstract

In this study, a hybrid semiartificial photosynthesis system based on chloroplast (CLP) and titanium oxide nanoparticles (TiO₂ NPs) was constructed. 2,6-Dichlorophenolindophenol (DCPIP) reduction by TiO₂/CLP complex and methylene blue (MB) reduction by TiO₂ were used to determine enhanced photogenerated electron transfer in this hybrid system. The DCPIP reduction by the TiO₂/CLP complex showed the same trend as MB reduction by TiO₂ as a function of concentration of TiO₂ NPs, indicating interception of photogenerated electrons in TiO₂ by CLP that leads to enhanced photosynthesis efficiency. Decreased photoluminescence intensity and shortened excited-state lifetime of the TiO₂/CLP complex compared to that of pure TiO₂ also support electron transfer from TiO₂ to CLP. Longer visible light absorption wavelength and increasing valence band edges reveal the narrower band gap of TiO₂/CLP, which finally results in the enhanced electron transfer from TiO₂ to CLP. Higher ferricyanide reduction and enhanced ATP formation with the TiO₂/CLP complex demonstrate the accelerated electron-transfer rate of the electron-transfer chain. This study reveals the mechanism of how TiO₂ interacts with CLP to enhance the photosynthesis via constructing a semiartificial photosynthesis system.