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Effects of Calcination Temperature on the Physical Properties and Hydrogen Evolution Activities of La 5 Ti 2 Cu(S 1‐ x Se x ) 5 O 7 Photocatalysts
Author(s) -
Nandy Swarnava,
Hisatomi Takashi,
Katayama Masao,
Minegishi Tsutomu,
Domen Kazunari
Publication year - 2018
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.201700275
Subject(s) - calcination , photocatalysis , materials science , solid solution , aqueous solution , particle size , visible spectrum , band gap , chemical engineering , nanotechnology , chemistry , catalysis , metallurgy , organic chemistry , optoelectronics , engineering
La 5 Ti 2 Cu(S 1‐ x Se x ) 5 O 7 (LTCS 1‐ x Se x O) solid solutions are found to function as visible‐light‐driven photocatalysts to evolve H 2 from aqueous solutions containing sacrificial electron donors. However, this photocatalytic activity is reduced with increasing Se concentrations because of excessive particle growth during calcination at high temperatures. In the present study, the physical properties and photocatalytic H 2 evolution activities of LTCS 1‐ x Se x O (0 ≤ x ≤ 0.6) solid solution photocatalysts synthesized by solid‐state reactions at varying temperatures are assessed. It is found that the photocatalyst particle sizes are reduced upon lowering the calcination temperature. In addition, the calcination temperature resulting in the highest photocatalytic H 2 evolution rates for NiS‐loaded LTCS 1‐ x Se x O is shown to become lower with increasing Se content. The H 2 evolution activity of LTCS 1‐ x Se x O (0.2 ≤ x ≤ 0.6) is improved several‐fold by optimizing the calcination temperature because the excessive growth of particles is avoided. The activity of these materials is further improved by coloading Pt and NiS cocatalysts. This work demonstrates the importance of controlling the particle size of narrow bandgap LTCS 1‐ x Se x O oxysulfoselenides so as to effectively utilize visible light during photocatalytic H 2 evolution.