Photoelectrical response of mesoporous nickel oxide decorated with size controlled platinum nanoparticles under argon and oxygen gas

• Published in: Catalysis today 2017-04, Vol.284, p.37-43
• Main Authors: Gómez-Pérez, Juan, Dobó, Dorina G., Juhász, Koppány L., Sápi, András, Haspel, Henrik, Kukovecz, Ákos, Kónya, Zoltán
• Format: Article
• Language: English
• Subjects: Mesoporous nickel-oxide; p-Type semiconductor; Photocatalysis; Photoelectrical response; Pt nanoparticles; Size effect
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2016.10.026

[Display omitted] •Pt/MNO has 3 times higher visible light photoresponse compared to the pristine MNO.•1.6nm Pt/MNO has higher photoresponse compared to 6.4nm and 7.9nm Pt/MNO.•The photoresponse is higher in Ar compared to O2 atmosphere.•Pt/MNO heterojunctions has a major effect on the photoresponse. The visible light photoelectrical properties of a p-type mesoporous nickel oxide (MNO) support was investigated upon the decoration of size controlled, 1.6nm, 6.4nm and 7.9nm Pt nanoparticles. The near room temperature photoelectrical response of the MNO was 3 times higher after decoration of 1.6nm Pt nanoparticles with a loading of 1wt%. MNO decorated with smaller Pt nanoparticles showed the highest photoresponse. The surrounding atmosphere has striking effect on the photoelectrical behavior, as adsorbed oxygen induced 32% lower photoelectrical response compared to that of argon. The noble metal nanoparticles show both electronic and chemical sensitization: the first functioning as an electron sink resulting in a new band structure of the photocatalyst, and the second interacting chemically with the oxygen and argon adsorbed from the environment. A model is proposed using heterojunctions theory comprising a new induced oxygen potential that may explain the lower photoresponse in the presence of oxygen.