Improved Photocatalytic Hydrogen Evolution on Tantalate Perovskites CsTaO 3 and LiTaO 3 by Strain-Induced Vacancies

Kaveh Edalati (1) , Keisuke Fujiwara (2) , Shuhei Takechi (3) , Qing Wang (4) , Makoto Arita (2) , Motonori Watanabe (1) , Xavier Sauvage (5) , Tatsumi Ishihara (1) , Zenji Horita (1)

1 WPI-I2CNER - International Institute for Carbon-Neutral Energy Research
2 DMS - Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka
3 Kyushu University [Fukuoka]
4 CIEE - College of Information and Electrical Engineering [Beijing]
5 GPM - Groupe de physique des matériaux

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.

Keywords: severe plastic deformation (SPD; ) high-pressure torsion (HPT); Photocatalysis; Lithium tantalate; Cesium tantalate; Oxygen vacancy; Severe plastic deformation (SPD); High-pressure torsion (HPT)

Domains: Physics [physics]; Condensed Matter [cond-mat]; Materials Science [cond-mat.mtrl-sci]

Kaveh Edalati, Keisuke Fujiwara, Shuhei Takechi, Qing Wang, Makoto Arita, et al.. Improved Photocatalytic Hydrogen Evolution on Tantalate Perovskites CsTaO 3 and LiTaO 3 by Strain-Induced Vacancies. ACS Applied Energy Materials, 2020, 3 (2), pp.1710-1718. ⟨10.1021/acsaem.9b02197⟩. ⟨hal-02521071⟩