催化学报

催化学报 ›› 2020, Vol. 41 ›› Issue (10): 1589-1602.DOI: 10.1016/S1872-2067(20)63555-0

• 论文 • 上一篇    下一篇

二价镍离子修饰TS-1分子筛纳米片用于有效光催化醇氧化及污染物降解

Imran Khana, 初小宇a,b, 刘彦铎a, Salman Khanc, 白林鹭a,b, 井立强a   

  1. a 黑龙江大学化学与化工材料学院, 教育部功能无机重点实验室, 黑龙江哈尔滨 150080;
    b 哈尔滨理工大学化学与环境工程学院, 黑龙江哈尔滨 150080;
    c 大连理工大学化工学院精细化工国家重点实验室, 辽宁大连 116024
  • 收稿日期:2020-02-23 修回日期:2020-03-29 出版日期:2020-10-18 发布日期:2020-08-15
  • 通讯作者: 白林鹭, 井立强
  • 基金资助:
    国家自然科学基金（U1805255，21706044）；国家教育部基金（213011A）；国家博士后基金（2017M621316）；黑龙江省自然科学基金（B2017006）；黑龙江省博士后基金（LBH-Z17187）.

Synthesis of Ni2+ cation modified TS-1 molecular sieve nanosheets as effective photocatalysts for alcohol oxidation and pollutant degradation

Imran Khana, Xiaoyu Chua,b, Yanduo Liua, Salman Khanc, Linlu Baia,b, Liqiang Jinga   

  1. a Department Key Laboratory of Functional Inorganic Materials Chemistry, Ministry of Education, School of Chemistry and Materials Science, International Joint Research Center and Lab for Catalytic Technology, Heilongjiang University, Harbin 150080, Heilongjiang, China;
    b School of Chemical and Environmental Engineering, Harbin University of Science and Technology, Harbin 150080, Heilongjiang, China;
    c State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China
  • Received:2020-02-23 Revised:2020-03-29 Online:2020-10-18 Published:2020-08-15
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (U1805255, 21706044), the Research Project of Chinese Ministry of Education (213011A), the China Postdoctoral Science Foundation (2017M621316), the Natural Science Foundation of Heilongjiang Province, China (B2017006), and the Postdoctoral Science Foundation of Heilongjiang Province, China (LBH-Z17187).

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摘要： 以O2为绿色氧化剂实现高效光催化有机物氧化转化过程如醇等有机物的选择性氧化及污染物降解是当前光催化发展的重要方向之一.成功实现高活性及高选择性的上述转化过程主要在于设计并制备有效的光催化材料.二氧化钛作为最广泛应用的光催化材料被报道用于光催化空气醇氧化选择性转化，但通常活性有限且因其表面催化活性位均为含有Ti-O6活性中心而具有较低的产物选择性.相比之下，同样作为Ti基材料的钛硅分子筛如TS-1分子筛具有高选择性的Ti-O4催化中心、丰富的孔结构及良好的稳定性，被广泛用于多种传统催化氧化反应.近年来，TS-1分子筛因具有光催化活性而成为一类具有工业应用潜力的光催化材料，特别是其独特的Ti-O4催化中心有望实现高选择性的光催化氧化转化.然而，其活性仍受限于较差的光生电荷分离，提升TS-1分子筛的电荷分离是促进其光催化活性的关键.
本工作以特定结构的季铵盐表面活性剂为结构导向剂，通过低温水热法成功制备了TS-1分子筛纳米片，并通过离子交换法于TS-1分子筛纳米片的离子交换位引入二价镍离子，显著地提升了其光催化醇氧化及污染物降解的反应活性.在全光下，最佳镍修饰样品表现出优异活性，苯甲醇转化率达到78.9%，对应产物苯甲醛选择性达到98.8%，收率为普通块状TS-1分子筛6倍，循环活性维持5次无明显降低.镍修饰TS-1分子筛纳米片的优异活性源于介孔的二维TS-1纳米片具有显著增大的比表面积以及提升的电荷分离.与块状TS-1分子筛相比，镍修饰TS-1纳米片具有更短的电荷传输距离.引入镍物种能够捕获光生电子，从而提升了电荷分离，同时可作为催化氧化剂O2活化的催化活性位.捕获剂实验证明，氧二负自由基为镍修饰TS-1纳米片光催化醇氧化过程的主要氧活性物种.本工作开启了一类具有工业应用潜质的用于光催化醇选择性氧化及污染物降解的高效、高选择性且廉价的钛硅分子筛基光催化剂，为同类型光催化反应催化剂制备提供策略.

关键词: TS-1纳米片, 光催化醇氧化, 电荷分离, Ni物种电子捕获, O2活化

Abstract: Improvement of the charge separation of titanosilicate molecular sieves is critical to their use as photocatalysts for oxidative organic transformations. In this work, MFI TS-1 molecular sieve nanosheets (TS-1 NS) were synthesized by a low-temperature hydrothermal method using a tailored diquaternary ammonium surfactant as the structure-directing agent. Introducing Ni2+ cations at the ion-exchange sites of the TS-1 NS framework signi?cantly enhanced its photoactivity in aerobic alcohol oxidation. The optimized Ni cation-functionalized TS-1 NS (Ni/TS-1 NS) provide impressive photoactivity, with a benzyl alcohol (BA) conversion of 78.9% and benzyl aldehyde (BAD) selectivity of 98.8% using O2 as the only oxidant under full light irradiation; this BAD yield is approximately six times greater than that obtained for bulk TS-1, and is maintained for five runs. The excellent photoactivity of Ni/TS-1 NS is attributed to the significantly enlarged surface area of the two-dimensional morphology TS-1 NS, extra mesopores, and greatly improved charge separation. Compared with bulk TS-1, Ni/TS-1 NS has a much shorter charge transfer distance. The as-introduced Ni species could capture the photoelectrons to further improve the charge separation. This work opens the way to a class of highly selective, robust, and low-cost titanosilicate molecular sieve-based photocatalysts with industrial potential for selective oxidative transformations and pollutant degradation.

Key words: TS-1 nanosheet, Photocatalytic alcohol oxidation, Charge separation, Ni species as electron capturer, O2 activation