High-field polarization boosting visible-light photocatalytic H2 evolution of narrow-bandgap semiconducting (1 − x)KNbO3–xBa(Ni1/2Nb1/2)O3−δ ferroelectric ceramics
| Autor: | Yuchen Lan, Baohua Zhu, Wenbin Tang, Jiwen Xu, Guanghui Rao, Liufang Meng, Changrong Zhou, Fei Liu, Xiao Gang Xue, Jiang Wang, Xiao Liu, Changlai Yuan |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | New Journal of Chemistry. 45:20296-20308 |
| ISSN: | 1369-9261 1144-0546 |
| Popis: | A depolarized electric field (Edp) of ferroelectrics to boost the carrier separation and migration rate is critical to promote the field of visible light photocatalytic hydrogen evolution (PHE). Here, the PHE performance of high-field poled semiconducting (1 − x)KNbO3–xBa(Ni1/2Nb1/2)O3−δ (abbreviated as (1 − x)KN-xBNN, x = 0, 0.02, 0.05, 0.10, and 0.20) ferroelectric ceramics were systematically studied under full spectrum (λ > 320 nm) and visible light (λ > 420 nm), respectively. Benefiting from their narrow bandgap and sub-bandgap, all the Ba, Ni-modified KN ceramic powders exhibited a PHE response under visible light irradiation. Notably, the visible light PHE rate of the high-field poled 0.95KN–0.05BNN ceramic powder can be promoted to 415.16 μmol g−1 h−1, which is 17.8-fold higher than that of the unpoled sample (23.26 μmol g−1 h−1). The boosting PHE rate in poled samples can be attributed to the high-field polarization of the material, which can significantly affect the lattice structure and cause an ordered ferroelectric-domain structure to form a depolarized electric field (Edp). EPR spectroscopy indicated that the poled 0.95KN–0.05BNN sample exhibited a superior catalytic activity of ˙OH evolution compared with its unpoled counterpart, suggesting the dependence of high photocatalytic performance on the unique field-induced polarization structure by an outer electric field. Moreover, a higher photo-excited transient photocurrent in the poled 0.95KN–0.05BNN specimen further proved the positive effect of Edp on the photovoltaic response. The formation of Edp in the semiconducting (1 − x)KN–xBNN ferroelectric favors the separation and transportation of photogenerated carriers. Thus, the synergistic effect of narrow bandgap and high-field polarization ability is the key to enhance the visible light photocatalysis of semiconducting ferroelectrics. Boosting the visible light photoelectrochemical catalytic activity of semiconducting (1 − x)KN–xBNN ferroelectrics through high-field polarization may provide a useful strategy to design new ferroelectric-based semiconductor materials. |
| Databáze: | OpenAIRE |
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