Enhanced photocatalytic hydrogen production performance of KNaNbO-based ferroelectric semiconductor ceramics by Nd/Ni modification at A/B sites and polarization

• Published in: New journal of chemistry 2024-03, Vol.48 (12), p.5495-555
• Main Authors: Sun, Qingyi, Yuan, Changlai, Liu, Xiao, Zhang, Xiaowen, Zhao, Jingtai, Zhou, Changrong, Rao, Guanghui, Su, Kaiyuan, Wang, Dong
• Format: Article
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d3nj05806a

In the photocatalytic processes of ferroelectric semiconductor materials, how to induce a depolarized electric field ( E dp ) by polarization to reduce the electron-hole recombination rate is still a big problem. Here, the ABO 3 -type K 0.5 Na 0.5 NbO 3 (KNN) material is modified by Nd and Ni elements at A/B sites to narrow the band gap and maintain the room-temperature ferroelectric behavior. The 0.96KNN-0.04NdNiO 3 sample shows the narrowed band gap (∼2.75 eV) and high residual polarization value (∼11.56 μC cm −2 ). After high-field poling, the hydrogen production rate of the sample in the full spectrum reaches 926.28 μmol g −1 h −1 , indicating an increase of approximately 5 times compared to the 170.45 μmol g −1 h −1 of the unpoled sample. The improved performance of photocatalytic hydrogen production mainly results from the reduction of band gap and the formation of E dp after polarization. The change in the position of the top of the valence band after sample polarization reveals that high-field poling can improve charge transport efficiency by energy band bending. The synergistic effect of a narrow band gap and high-field polarization significantly enhances the hydrogen production efficiency of the sample.