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Reduction of nitrate ions into nitrite and ammonia over some photocatalysts

Journal Article · · Journal of Catalysis; (United States)

The authors have previously report that nitrate was quantitatively reduced by Ti[sup 3+] to form ammonia on the surface of thermally reduced TiO[sub 2] and Pt-TiO[sub 2] powders in the absence of light and that the photocatalytic reduction of nitrate to form ammonia proceeded on a Pt-TiO[sub 2] catalyst at room temperature. Nitrate is reduced to ammonia by hydrogen adsorbed on supported platinum even under dark conditions. The hydrogen absorbed on platinum in the present study is supplied by the photoreduction of water in the photocatalytic cycle. This process seems to be similar to those observed in ecological systems, where reduction of nitrate to ammonia proceeds in the dark phase of photosynthesis and the reducing power is supplied from substrates formed by the photoreduction. Thus, the photocatalytic reduction of nitrate is important for energy conversion by artifical photosynthesis and pollution control. In this paper, the reduction of nitrate was studied over various photocatalysts (native and modified TiO[sub 2], SrTiO[sub 3], K[sub 4]Nb[sub 6]O[sub 17], In[sub 2]O[sub 3], and WO[sub 3]) under some different conditions, and the relationship between activity and reaction conditions (photocatalyst composition and solution acidity) was revealed.

OSTI ID:
6915464
Journal Information:
Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 135:1; ISSN 0021-9517; ISSN JCTLA5
Country of Publication:
United States
Language:
English