原位低场核磁共振弛豫法定量监测光催化Cr(Ⅵ)还原反应
收稿日期: 2020-03-09
网络出版日期: 2020-05-06
基金资助
国家自然科学基金资助项目(21603073)
A Quantitative Study of Photocatalytic Reduction of Cr(Ⅵ) by Operando Low-Field NMR Relaxometry
Received date: 2020-03-09
Online published: 2020-05-06
本文利用原位低场核磁共振（LF-NMR）技术在真实固液反应环境中对光催化还原Cr（Ⅵ）反应进行了定量研究，并对Ag纳米颗粒负载量不同的Ag担载石墨相氮化碳复合光催化剂（Ag/g-C3N4）在可见光照射下催化Cr（Ⅵ）还原为Cr（Ⅲ）的性能进行了研究.研究发现，Ag纳米颗粒负载（负载量分别为1 wt.%、2 wt.%、5 wt.%和10 wt.%）可以有效提高g-C3N4的光催化性能；且负载量为5 wt.%时光催化性能最优，为无Ag负载的g-C3N4的4倍.此外，本文还通过横向弛豫时间（T2）定量分析了反应体系中顺磁性Cr（Ⅲ）离子的浓度，证实了采用LF-NMR弛豫法评价光催化Cr（Ⅵ）还原反应性能的可行性.
牛星星 , 白志杰 , 杨翼 , 高杨文 , 王雪璐 , 姚叶锋 . 原位低场核磁共振弛豫法定量监测光催化Cr(Ⅵ)还原反应[J]. 波谱学杂志, 2021 , 38(3) : 403 -413 . DOI: 10.11938/cjmr20202815
In this work, operando low-field nuclear magnetic resonance (LF-NMR) technology was used to quantitatively study the photocatalytic reduction of Cr(Ⅵ) in a real solid-liquid reaction environment. The performance of Ag/g-C3N4 photocatalysts with different loadings of Ag for the photocatalytic reduction of aqueous Cr(Ⅵ) to Cr(Ⅲ) under visible-light irradiation was systematically investigated. The results showed that the addition of Ag cocatalysts (Ag loading amount: 1 wt.%, 2 wt.%, 5 wt.%, and 10 wt.%) significantly enhanced the photocatalytic performance of g-C3N4 photocatalysts, while the optimal content of Ag loading was 5 wt.%, which was greater than that of pristine g-C3N4 by a factor of 4.0. Furthermore, we carried out a quantitative analysis on the concentration of paramagnetic Cr(Ⅲ) ions in solution by using the transverse relaxation time (T2) values, and proved the viability of employing operando LF-NMR relaxometry for monitoring the photocatalytic Cr(Ⅵ) reduction performance.
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