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Solar Water Splitting by TiO 2 /CdS/Co–Pi Nanowire Array Photoanode Enhanced with Co–Pi as Hole Transfer Relay and CdS as Light Absorber
Author(s) -
Ai Guanjie,
Li Hongxing,
Liu Shaopei,
Mo Rong,
Zhong Jianxin
Publication year - 2015
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201502461
Subject(s) - photocurrent , materials science , water splitting , nanowire , electrochemistry , electrode , absorption (acoustics) , visible spectrum , photochemistry , chemical engineering , optoelectronics , photocatalysis , catalysis , chemistry , biochemistry , engineering , composite material
The cobalt phosphate water oxidation catalyst (Co–Pi WOC) stabilized, CdS sensitized TiO 2 nanowire arrays for nonsacrificial solar water splitting are reported. In this TiO 2 /CdS/Co–Pi photoanode, the Co–Pi WOC acts as hole transfer relay to accelerate the surface water oxidation reaction, CdS serves as light absorber for wider solar spectra harvesting, and TiO 2 matrix provides direct pathway for electron transport. This triple TiO 2 /CdS/Co–Pi hybrid photoanode exhibits much enhanced photocurrent density and negatively shifts in onset potential, resulting in 1.5 and 3.4 times improved photoconversion efficiency compared to the TiO 2 /CdS and TiO 2 photoanode, respectively. More importantly, the TiO 2 /CdS/Co–Pi shows significantly improved photoelectrochemical stability compared to the TiO 2 /CdS electrode, with ≈72% of the initial photocurrent retained after 2 h irradiation. The reason for the promoted performance is discussed in detail based on electrochemical measurements. This work provides a new paradigm for designing 1D nanoframework/light absorber/WOC photoanode to simultaneously enhance light absorption, charge separation, and transport and surface water oxidation reaction for efficient and stable solar fuel production.