Chen Fang, Ma Zhaoyu, Ye Liqun, Ma Tianyi, Zhang Tierui, Zhang Yihe, Huang Hongwei
Beijing Key Laboratory of Materials Utilization of Nonmetallic Mineralsand Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing, 100083, China.
Nanyang Normal University, Nanyang, 473061, P. R. China.
Adv Mater. 2020 Mar;32(11):e1908350. doi: 10.1002/adma.201908350. Epub 2020 Feb 6.
Prompt recombination of photogenerated electrons and holes in bulk and on the surface of photocatalysts harshly impedes the photocatalytic efficiency. However, the simultaneous manipulation of photocharges in the two locations is challenging. Herein, the synchronous promotion of bulk and surface separation of photoinduced charges for prominent CO photoreduction by coupling macroscopic spontaneous polarization and surface oxygen vacancies (OVs) of BiOIO single crystals is reported. The oriented growth of BiOIO single-crystal nanostrips along the [001] direction, ensuing substantial well-aligned IO polar units, renders a large enhancement for the macroscopic polarization electric field, which is capable of driving the rapid separation and migration of charges from bulk to surface. Meanwhile the introduction of surface OVs establishes a local electric field for charge migration to catalytic sites on the surface of BiOIO nanostrips. Highly polarized BiOIO nanostrips with ample OVs demonstrate outstanding CO reduction activity for CO production with a rate of 17.33 µmol g h (approximately ten times enhancement) without any sacrificial agents or cocatalysts, being one of the best CO reduction photocatalysts in the gas-solid system reported so far. This work provides an integrated solution to governing charge movement behavior on the basis of collaborative polarization from bulk and surface.
光催化剂体相和表面光生电子与空穴的快速复合严重阻碍了光催化效率。然而，同时操控这两个位置的光电荷具有挑战性。在此，报道了通过耦合BiOIO单晶的宏观自发极化和表面氧空位（OVs），同步促进光生电荷在体相和表面的分离，以实现显著的CO光还原。BiOIO单晶纳米带沿[001]方向的取向生长，产生大量排列良好的IO极性单元，极大增强了宏观极化电场，该电场能够驱动电荷从体相快速分离并迁移到表面。同时，表面OVs的引入建立了一个局部电场，用于电荷迁移到BiOIO纳米带表面的催化位点。具有大量OVs的高度极化BiOIO纳米带在没有任何牺牲剂或助催化剂的情况下，表现出出色的CO还原活性，CO生成速率为17.33 µmol g h（提高了约10倍），是迄今为止报道的气固体系中最佳的CO还原光催化剂之一。这项工作提供了一种基于体相和表面协同极化来控制电荷移动行为的综合解决方案。
