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Engineering the TiO 2 –Graphene Interface to Enhance Photocatalytic H 2 Production
Author(s) -
Liu Lichen,
Liu Zhe,
Liu Annai,
Gu Xianrui,
Ge Chengyan,
Gao Fei,
Dong Lin
Publication year - 2014
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201300941
Subject(s) - graphene , photocatalysis , materials science , x ray photoelectron spectroscopy , nanocomposite , crystal (programming language) , nanotechnology , chemical engineering , band gap , photoluminescence , catalysis , optoelectronics , chemistry , organic chemistry , engineering , programming language , computer science
In this work, TiO 2 –graphene nanocomposites are synthesized with tunable TiO 2 crystal facets ({100}, {101}, and {001} facets) through an anion‐assisted method. These three TiO 2 –graphene nanocomposites have similar particle sizes and surface areas; the only difference between them is the crystal facet exposed in TiO 2 nanocrystals. UV/Vis spectra show that band structures of TiO 2 nanocrystals and TiO 2 –graphene nanocomposites are dependent on the crystal facets. Time‐resolved photoluminescence spectra suggest that the charge‐transfer rate between {100} facets and graphene is approximately 1.4 times of that between {001} facets and graphene. Photoelectrochemical measurements also confirm that the charge‐separation efficiency between TiO 2 and graphene is greatly dependent on the crystal facets. X‐ray photoelectron spectroscopy reveals that TiC bonds are formed between {100} facets and graphene, while {101} facets and {001} facets are connected with graphene mainly through TiOC bonds. With TiC bonds between TiO 2 and graphene, TiO 2 ‐100‐G shows the fastest charge‐transfer rate, leading to higher activity in photocatalytic H 2 production from methanol solution. TiO 2 ‐101‐G with more reductive electrons and medium interfacial charge‐transfer rate also shows good H 2 evolution rate. As a result of its disadvantageous electronic structure and interfacial connections, TiO 2 ‐001‐G shows the lowest H 2 evolution rate. These results suggest that engineering the structures of the TiO 2 –graphene interface can be an effective strategy to achieve excellent photocatalytic performances.