Details

Autor(en) / Beteiligte

• Tang, Wenbin
• Xue, Xiaogang
• Yuan, Changlai
• Chen, Jun
• Miao, Lei
• Feng, Qin
• Xu, Jiwen
• Rao, Guanghui
• Wang, Jiang
• Zhou, Changrong
• Guo, Yiping

Titel

Visible-light photocatalytic hydrogen production in a narrow-bandgap semiconducting La/Ni-modified KNbO ferroelectric and further enhancement high-field poling

Ist Teil von

• Journal of materials chemistry. A, Materials for energy and sustainability, 2022-03, Vol.1 (13), p.7238-725

Erscheinungsjahr

2022

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Compared with traditional wide-bandgap oxide ferroelectrics that exhibit excellent UV photocatalysis, narrow-bandgap semiconducting ferroelectrics demonstrate broad application prospects in the field of visible-light photocatalysis. However, due to significant current leakage and weakening of ferroelectricity in most semiconducting ferroelectrics, establishing high-field poling via an external electric field to boost photocatalytic activity further is difficult. Therefore, balancing the semiconductivity and ferroelectricity of such materials is challenging. Here, a novel visible-light-driven semiconducting ferroelectric photocatalyst of La/Ni-modified KNbO 3 , namely, (1 − x ) KNbO 3 - x LaNiO 3− δ with x = 0.00-0.04, is successfully prepared via sintering. Similar to traditional wide-bandgap KNbO 3 ferroelectrics, semiconducting ferroelectrics also manifest an excellent photocatalytic hydrogen evolution (PHE) rate under simulated sunlight (1169.7 µmol g −1 h −1 ). The 0.99KNbO 3 -0.01LaNiO 3− δ composition can exhibit visible-light PHE activity (40.1 µmol g −1 h −1 ). Moreover, semiconducting ferroelectrics at room temperature can still be poled under a high external electric field, and the visible PHE rate of 0.99KNbO 3 -0.01LaNiO 3− δ can be increased by 16 times (642.0 µmol g −1 h −1 ) via high-field poling. This remarkable visible PHE rate observed in the modified system is associated with the very narrow bandgap of 1.45-1.24 eV and the enhancement of carrier separation efficiency by high-field poling. This work provides a feasible solution for designing ferroelectric-based oxide photocatalysts with excellent visible-light activity and insights into the polarisation mechanisms of semiconducting ferroelectrics. The poled (1− x ) KNbO 3 - x LaNiO 3− δ ferroelectric semiconductors obtained an enhanced visible-light photocatalytic hydrogen evolution rate of 642.0 µmol g −1 h −1 , which is at least 16 times that of the unpoled sample (40.1 µmol g −1 h −1 ).