In:
Israel Journal of Chemistry, Wiley, Vol. 22, No. 2 ( 1982-01), p. 168-172
Abstract:
Photochemical water splitting (H 2 O → H 2 + 1/2O 2 ) has been shown to occur on UV irradiation of aqueous suspensions of strontium titanate, modified by surface photodeposition of rhodium species. 7 Further improvement of the catalytic materials has now been achieved, using thermal deposition techniques. The most active material, prepared by heating rhodium chloride impregnated SrTiO 3 powder at 500°C in air, allowed one to produce appreciable quantities of (H 2 + 1/2O 2 ) gas and to reach high turnover numbers on the catalytic material. The photolysis efficiency presents a strong pH dependence with an optimum around pH ∼ 14 and increases markedly when the wavelength of the light decreases from 400 to 300 nm. The amount of rhodium deposited also has a marked effect with an optimum at about 0.2–0.3% Rh by weight. ESCA studies have provided information about the nature of the catalytic deposit and about its relation to the activity of the materials. Catalytic efficiency and mechanistic aspects are discussed. The oxidation state of the rhodium species has a drastic influence: whereas SrTiO 3 loaded with reduced rhodium shows no catalytic activity, the efficiency increases on progressive oxidation of the deposited metal to surface rhodium(III) species, as detected by ESCA. The photoactive step may involve both band‐gap excitation of the semi‐conductor support and direct UV excitation of the deposited Rh(III) species.
Type of Medium:
Online Resource
ISSN:
0021-2148
,
1869-5868
DOI:
10.1002/ijch.198200032
Language:
English
Publisher:
Wiley
Publication Date:
1982
detail.hit.zdb_id:
2066481-3
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