在 B 掺杂 g-CN 上的 BiVO 混合相的偶然组装：用于光催化 O2 析出和 Cr(VI)还原的合适 p-n 异质结。
Serendipitous Assembly of Mixed Phase BiVO on B-Doped g-CN: An Appropriate p-n Heterojunction for Photocatalytic O evolution and Cr(VI) reduction.
机构信息
Centre for Nanoscience and Nanotechnology , Siksha 'O' Anusandhan , Bhubaneswar 751030 , India.
出版信息
Inorg Chem. 2019 Sep 16;58(18):12480-12491. doi: 10.1021/acs.inorgchem.9b02309. Epub 2019 Aug 28.
Type II p-n heterojunction B-doped g-CN/BiVO moieties have been fabricated by depositing n-type BiVO on the surface of p-type 1 wt % B-doped g-CN for the first time. The materials were characterized by PXRD, XPS, UV-vis DRS, IR, PL, and Raman analysis. The photocatalytic activities of as synthesized samples were studied toward reduction of Cr(VI) and water splitting reaction to generate oxygen. The results reveal that Type II p-n heterojunction considerably enhance the photocatalytic activity as compared to neat n-type BiVO and p-type B-doped g-CN. 50% BiVO/B-doped g-CN heterostructure exhibited the best photocatalytic activity, which is 7.9-fold higher than that of BiVO and followed by a pseudo first order kinetics with apparent first order rate constant of 0.063 min. Again the heterojunction is able to produce 4.2 times higher oxygen evolution value as related to pristine BiVO. The superior photocatalytic activity is attributed to higher visible light utilization and lower recombination of electron-hole pairs by creating a p-n junction. PXRD and HRTEM data suggest the formation of mixed phase monoclinic and tetragonal BiVO thereby creating a heterojunction for the improvement of the photocatalytic performances. The formation of mixed-phase BiVO is attributed to the high temperature calcination as well as surface energy of B-doped g-CN. The oxygen vacancy in the system is confirmed through XPS and Raman analysis. Moreover, the excellent photocurrent response by the designed photocatalyst at lower overpotential and decrease in carrier recombination as compared to bulk one, studied from LSV and electrochemical impedance spectroscopy, validate the unique photocatalytic activity of the catalyst. The formation of the p-n heterojunction is confirmed from a Mott-Schottky analysis. The work shed new light on the assembly of the p-n heterojunction, showing excellent photocatalytic properties in a simple way.
首次通过在 p 型 1wt%B 掺杂 g-CN 表面沉积 n 型 BiVO 制备了 II 型 p-n 异质结 B 掺杂 g-CN/BiVO 基。通过 PXRD、XPS、UV-vis DRS、IR、PL 和 Raman 分析对材料进行了表征。研究了所合成样品对 Cr(VI)还原和水分解反应生成氧气的光催化活性。结果表明，与纯 n 型 BiVO 和 p 型 B 掺杂 g-CN 相比，II 型 p-n 异质结大大提高了光催化活性。50% BiVO/B 掺杂 g-CN 异质结构表现出最佳的光催化活性，比 BiVO 高 7.9 倍，随后遵循准一级动力学，表观一级速率常数为 0.063 min。再次，与原始 BiVO 相比，异质结能够产生高 4.2 倍的氧气析出值。优异的光催化活性归因于可见光利用率的提高和电子-空穴对复合的降低，通过创建 p-n 结来实现。PXRD 和 HRTEM 数据表明，形成了混合相单斜和四方相 BiVO，从而改善了光催化性能。混合相 BiVO 的形成归因于高温煅烧以及 B 掺杂 g-CN 的表面能。通过 XPS 和 Raman 分析证实了体系中的氧空位。此外，与体相相比，设计的光催化剂在较低的过电势下具有出色的光电流响应和载流子复合减少，通过 LSV 和电化学阻抗谱进行了研究，验证了催化剂独特的光催化活性。从 Mott-Schottky 分析证实了 p-n 异质结的形成。这项工作为 p-n 异质结的组装提供了新的思路，以简单的方式展示了优异的光催化性能。
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