Improvement of photocatalytic activity of tantalum nitride by ammonothermal treatment at high pressure
- Department of Applied Chemistry, School of Science and Technology, Meiji University, Tama-ku, Kawasaki 214-8571 (Japan)
Tantalum nitride (Ta{sub 3}N{sub 5}) was treated under ammonothermal conditions with the ammonia pressure of 10 to 100 MPa at 823 K for 24 h to enhance the photocatalytic activity for hydrogen evolution from aqueous methanol solution under visible light irradiation. The rates of hydrogen evolution for all treated Ta{sub 3}N{sub 5} were faster than those for untreated Ta{sub 3}N{sub 5}. Treated Ta{sub 3}N{sub 5} showed higher enhanced activity for hydrogen evolution when treated with high-pressure ammonia at more than 50 MPa. The photocatalytic activity for hydrogen evolution of treated Ta{sub 3}N{sub 5}, related to the amount of defects, is due to reduced tantalum species. The enhancement in the activity is brought about by a decrease in surface defects, which contributes to improved electron transfer from the surface of Ta{sub 3}N{sub 5} to the loaded Pt co-catalyst. - Graphical abstract: Time course of H{sub 2} evolution for 0.5 wt% Pt- loaded Ta{sub 3}N{sub 5}. (a) As-synthesized Ta{sub 3}N{sub 5}. (b)-(e) Samples treated at 823 K for 5 h with (b) 10 MPa of N{sub 2}, (c) 10 MPa of NH{sub 3}, (d) 50 MPa of NH{sub 3}, and (e) 100 MPa of NH{sub 3}. Highlights: Black-Right-Pointing-Pointer Ta{sub 3}N{sub 5} was treated with high-pressure N{sub 2} or NH{sub 3} to enhance photocatalytic activity. Black-Right-Pointing-Pointer The hydrogen evolution activity of Ta{sub 3}N{sub 5} was more enhanced with treatment with NH{sub 3}. Black-Right-Pointing-Pointer Treatment with ammonia pressure above 50 MPa indicated a more improved activity. Black-Right-Pointing-Pointer The results of UV-vis DRS suggested decreased surface defects of treated Ta{sub 3}N{sub 5}.
- OSTI ID:
- 22012165
- Journal Information:
- Journal of Solid State Chemistry, Vol. . 191; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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