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Designing Photocatalysts for Hydrogen Evolution: Are Complex Preparation Strategies Necessary to Produce Active Catalysts?
Author(s) -
Grewe Tobias,
Tüysüz Harun
Publication year - 2015
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.201500774
Subject(s) - photocatalysis , catalysis , tantalum , hydrogen production , methanol , materials science , alkoxide , amorphous solid , hydrogen , chemical engineering , oxide , inorganic chemistry , chemistry , organic chemistry , engineering , metallurgy
A facile synthetic route for the preparation of highly active photocatalysts was developed. The protocol involves the preparation of a photocatalyst through the direct injection of metal alkoxide precursors into solutions in a photoreactor. As a proof of concept, a tantalum oxide based photocatalyst was chosen as a model system. Tantalum ethoxide [Ta(OEt) 5 ] was injected rapidly into a photoreactor filled with a water/methanol mixture, and a TaO x (OH) y composite formed and was able to produce hydrogen under light illumination. Compared to commercial and mesostructured Ta 2 O 5 and NaTaO 3 materials, TaO x (OH) y produced by direct injection shows superior hydrogen production activity. Notably, the samples prepared by direct injection are amorphous; however, their photocatalytic performance is much higher than those of their crystalline equivalents. If Ta(OEt) 5 was dispersed in methanol before injection, an amorphous framework with higher surface area and larger pore volume was formed, and the hydrogen production rate increased further. The addition of a sodium precursor during the injection further boosted the photocatalytic activity. Furthermore, this concept has also been applied to a titanium‐based photocatalyst, and a much better hydrogen production rate has been obtained in comparison with that of commercial TiO 2 (P25‐Degussa); therefore, the direct‐injection synthesis is a flexible method that opens the door to the facile preparation of highly active nanostructured photocatalysts for hydrogen production.