Photocatalytic Activity of Ga 2 O 3 Supported on Al 2 O 3 for Water Splitting and CO 2 Reduction

• Published in: ACS omega 2019-03, Vol.4 (3), p.5451-5458
• Main Authors: Ito, Ryota, Akatsuka, Masato, Ozawa, Akiyo, Kato, Yuma, Kawaguchi, Yu, Yamamoto, Muneaki, Tanabe, Tetsuo, Yoshida, Tomoko
• Format: Article
• Language: English
• ISSN: 2470-1343; 2470-1343
• DOI: 10.1021/acsomega.9b00048

We have examined the photocatalytic activity of Ga O supported on Al O (Ga O /Al O catalyst) without a noble metal cocatalyst for water splitting and reduction of CO with water under UV light irradiation by changing the loading amount of Ga O . All prepared Ga O /Al O catalysts show photocatalytic activities for both water splitting and CO reduction, and their activities are significantly improved compared to those of nonsupported Ga O and Al O . The water splitting is dominated for Ga O /Al O with less than 1.0 vol % of Ga O loaded, whereas the CO reduction, for higher Ga O -loaded samples (2.6, 4.2 vol %). Crystalline structure characterizations of Ga O /Al O catalysts indicate that active sites for both reactions are different. The water splitting proceeds on nanometer-sized Ga O rods dispersed on an Al O support consisting of a little distorted α-Ga O phase. On the other hand, the CO reduction proceeds on sub-micrometer-sized Ga O particles consisting of mixed phases of α-Ga O and γ-Ga O or with appearance of boundaries between the α and γ phases, which plays a critical role. Al O used as the support of the Ga O particles does not seem to play an important role in the photocatalytic CO reduction.