An order/disorder/water junction system for highly efficient co-catalyst-free photocatalytic hydrogen generation

Surface engineering of TiO 2 is faced with the challenge of high solar-to-hydrogen conversion efficiency. Recently, surface-disordered TiO 2 , referred to as black TiO 2 , which can absorb both visible and near-infrared solar light, has triggered an explosion of interest in many important applicatio...

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Bibliographic Details
Published in:Energy & environmental science 2016-02, Vol.9 (2), p.499-53
Main Authors: Zhang, Kan, Wang, Luyang, Kim, Jung Kyu, Ma, Ming, Veerappan, Ganapathy, Lee, Chang-Lyoul, Kong, Ki-jeong, Lee, Hyoyoung, Park, Jong Hyeok
Format: Article
Language:English
Subjects:
Disorders
Electrolytes
Evolution
Hydrogen
Nanoparticles
Photocatalysis
Surface reactions
Titanium dioxide
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Summary:Surface engineering of TiO 2 is faced with the challenge of high solar-to-hydrogen conversion efficiency. Recently, surface-disordered TiO 2 , referred to as black TiO 2 , which can absorb both visible and near-infrared solar light, has triggered an explosion of interest in many important applications. Unfortunately, the mechanism underlying the improved photocatalytic effect from an amorphous surface layer remains unclear and seems to contradict conventional wisdom. Here, we demonstrate selectively "disorder engineered" Degussa P-25 TiO 2 nanoparticles using simple room-temperature solution processing, which maintain the unique three-phase interfaces composed of ordered white-anatase and disordered black-rutile with open structures for easy electrolyte access. The strong reducing agent in a superbase, which consists of lithium in ethylenediamine (Li-EDA), can disorder only the white-rutile phase of P-25, leaving behind blue coloured TiO 2 nanoparticles. The order/disorder/water junction created by the blue P-25 can not only efficiently internally separate electrons/holes through type-II bandgap alignment but can also induce a strong hydrogen (H 2 ) evolution surface reaction in the sacrificial agent containing electrolyte. As a result, the blue P-25 exhibited outstanding H 2 production rates of 13.89 mmol h −1 g −1 using 0.5 wt% Pt (co-catalyst) and 3.46 mmol h −1 g −1 without using any co-catalyst. Order/disorder interfacial engineering realizes highly efficient co-catalyst free hydrogen generation.
ISSN:1754-5692
1754-5706
DOI:10.1039/c5ee03100a