Phosphate group grafted twinned BiPO4 with significantly enhanced photocatalytic activity: Synergistic effect of improved charge separation efficiency and redox ability
Phosphate group grafted twinned BiPO4 with significantly enhanced photocatalytic activity: Synergistic effect of improved charge separation efficiency and redox ability
复制标题
磷酸基团接枝孪晶BiPO4显着增强光催化活性：提高电荷分离效率和氧化还原能力的协同效应
DOI：
10.1016/j.apcatb.2018.04.036
复制
发表时间：
2018-10-15
影响因子：
22.1
通讯作者：
Hou, Jun
中科院分区：
文献类型：
--
作者：
Guo, Yan;Wang, Peifang;Hou, Jun
基于太阳能的光催化技术是缓解环境问题的一种潜在途径。光催化剂的表面性质和光生空间电荷的分离效率对提高其光催化降解废水中有机污染物的活性具有重要意义。本工作采用简单的两步法可控地合成了表面相结的磷酸基接枝孪晶BiPO4。X射线衍射结果表明，在孪晶BiPO4中形成了nMBIP和mMBIP两种晶相。用高分辨电子显微镜证实了BiPO4中相结层的形成。XPS光谱证实PO43-成功接枝在孪晶BiPO4表面。由于形成了相连接，孪生BiPO4对亚甲基蓝(MB)和卡马西平(CBZ)的表观降解速率常数分别比原始BiPO4提高了5.3和5.0倍。在相结表面接枝磷酸盐后，MB和CBZ的表观降解速率常数进一步提高，分别是孪晶BiPO4的3.0倍和5.2倍。用高效液相色谱-电喷雾串联质谱仪对CBZ的光催化中间体进行了检测，提出了CBZ的还原降解途径。瞬时光电流响应、光致发光和Mott-Schottky分析证实，具有相结的双晶BiPO4接枝磷酸盐基团对MB和CBZ降解的光催化活性的提高归因于更快的转移、有效的分离和提高了光生载流子的氧化还原能力。
The photocatalytic technology based on solar energy is a potential approach to mitigate environmental problem. The surface property of photocatalysts and the separation efficiency of photo-generated spatial charge are considerably important to enhance their photocatalytic activity in the decomposition of organic pollutants in wastewater. In this work, phosphate group grafted twinned BiPO4 with surface phase junction were controllably synthesized by a facile two-step method. XRD results showed that two crystal phases of nMBIP and mMBIP were formed in the twinned BiPO4. The formation of phase junction in BiPO4 was also validated by HRTEM. XPS spectra confirmed that PO43- successfully grafted on the surface of the twinned BiPO4. The apparent rate constants of the twinned BiPO4 for degradation of methylene blue (MB) and carbamazepine (CBZ) improved 5.3 and 5.0 times respectively compared to pristine BiPO4 because of the formed phase junction. After phosphate grafting on the surface of phase junction, the apparent rate constants for MB and CBZ degradation were further boosted, which were 3.0 and 5.2 times as high as that of twinned BiPO4. The photocatalytic intermediates of CBZ were detected by HPLC-ESI-MS/MS, and a deductive degradation pathway of CBZ was proposed. Transient photocurrent responses, PL and Mott-Schottky analysis verified that the enhanced photocatalytic activity of phosphate group grafted twinned BiPO4 with phase junction for the degradation of MB and CBZ was ascribed to faster transfer, efficient separation and improved redox ability of photo-induced charge carriers.