Improved Photocatalytic Hydrogen Evolution on Tantalate Perovskites CsTaO3 and LiTaO3 by Strain-Induced Vacancies

• Published in: ACS applied energy materials 2020-02, Vol.3 (2), p.1710-1718
• Main Authors: Edalati, Kaveh, Fujiwara, Keisuke, Takechi, Shuhei, Wang, Qing, Arita, Makoto, Watanabe, Motonori, Sauvage, Xavier, Ishihara, Tatsumi, Horita, Zenji
• Format: Article
• Language: English
• ISSN: 2574-0962; 2574-0962
• DOI: 10.1021/acsaem.9b02197

Tantalate perovskites are potential candidates for photocatalytic hydrogen production without cocatalyst addition; however, these oxides have large bandgaps, which result in their low photocatalytic activity. In this study, to enhance the photocatalytic activity, CsTaO3 as a potential photocatalyst and LiTaO3 as a well-known photocatalyst are subjected to severe plastic strain using the high-pressure torsion (HPT) method. Both superstrained tantalates exhibit optical bandgap narrowing and ∼2.5 times enhancement of photocatalytic hydrogen production. Such bandgap narrowing is mainly due to the formation of oxygen vacancies, although nanocrystal formation and partial amorphization also occur by straining. These findings not only introduce CsTaO3 as a photocatalyst but also confirm the significance of strain-induced vacancies on the photocatalytic activity of perovskites.