Investigations on the effect of Cu2+/Cu1+ redox couples and oxygen vacancies on photocatalytic activity of treated LaNi1−xCuxO3 (x=0.1, 0.4, 0.5)

✍ Scribed by Juanjuan Li; Jiaolong Zeng; Lishan Jia; Weiping Fang

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 965 KB
• Volume: 35
• Category: Article
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2010.08.140

✦ Synopsis

Perovskite-like oxides LaNi 1Àx Cu x O 3 (x ¼ 0.1, 0.4, 0.5) were prepared by means of the citric acid complexing method. TPR revealed the incorporation of Cu into the perovskite lattice increased the reducibility of the catalyst. After LaNi 1Àx Cu x O 3 were pretreated in H 2 for 2 h at certain low temperature, the material still retained its perovskite structure and oxygen vacancies were generated in the lattice. DRS showed that narrowing of band-gap of reduced LaNi 1Àx Cu x O 3 was governed by the crystalline structure and the defect in the catalyst. In the photocatalytic water splitting experiment, 200 and 250 C-reduced LaNi 0.6 Cu 0.4 O 3 , 200 C-reduced LaNi 0.5 Cu 0.5 O 3 possessed the high and colse catalytic activity. XPS showed that the molar ratio of Cu 2þ /Cu 1 z1 and lattice oxygen/adsorb oxygen z 0.2 in the catalysts had high catalytic activity. According to the outcome of our experiments, we conclude that there is a balance relation either between oxygen vacancies and catalytic activity or between Cu 2þ /Cu 1þ redox couples and catalytic performance of these materials for hydrogen production from photocatalytic water splitting.

Enhancement of hydrogen yield can be attributed to the small band-gap and the lowering the recombination probability for electron-hole pairs.