Keggin-type SiW12 encapsulated in MIL-101(Cr) as efficient heterogeneous photocatalysts for nitrogen fixation reaction

Senda Su; Xiaoman Li; Xu Zhang; Jingting Zhu; Guodong Liu; Mengyao Tan; Yingying Wang; Min Luo

doi:10.1016/j.jcis.2022.04.006

Keggin-type SiW₁₂ encapsulated in MIL-101(Cr) as efficient heterogeneous photocatalysts for nitrogen fixation reaction

J Colloid Interface Sci. 2022 Sep:621:406-415. doi: 10.1016/j.jcis.2022.04.006. Epub 2022 Apr 8.

Authors

Senda Su¹, Xiaoman Li², Xu Zhang¹, Jingting Zhu³, Guodong Liu¹, Mengyao Tan¹, Yingying Wang¹, Min Luo⁴

Affiliations

¹ State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, School of Chemistry and Chemical Engineering, Ningxia University, Yinchuan, Ningxia 750021, PR China.
² State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, School of Chemistry and Chemical Engineering, Ningxia University, Yinchuan, Ningxia 750021, PR China. Electronic address: lixm2017@nxu.edu.cn.
³ International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, PR China.
⁴ State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, School of Chemistry and Chemical Engineering, Ningxia University, Yinchuan, Ningxia 750021, PR China. Electronic address: luominjy@nxu.edu.cn.

PMID: 35472667
DOI: 10.1016/j.jcis.2022.04.006

Abstract

The incorporation of polyoxometalates (POMs) in metal-organic frameworks (MOFs) with host-guest structure have proven to be effective strategy to rational design of heterogeneous catalysis. In this study, the Keggin-type POM@MIL-101(Cr) composite catalysts (PMo₁₂, PW₁₂ and SiW₁₂) are synthesized for nitrogen fixation reaction without sacrificial agents at room temperature in the first time. The SiW₁₂ molecules are encapsulated in smaller cavities of MIL-101(Cr) by solvothermal method and in larger cavities by impregnation method, respectively. Solvothermal synthesized catalyst has a performance of 75.56 μmol·h^-1·g^-1_cat and TOF value of 1.95 h^-1, which are about 10 and 88 times than that of Na₄SiW₁₂O₄₀. The excellent performance is ascribed to the synergistic effect of SiW₁₂ and MIL-101(Cr). The MIL-101(Cr) adsorbs a large amount of N₂ and generates sufficiently photogenerated electrons under sunlight irradiation, and electrons quickly transfer to the SiW₁₂ through hydrogen bonds. Moreover, the agglomeration effect of the homogeneous catalyst SiW₁₂ is weakened due to encapsulation with more exposed active sites. This work provides a feasible route to design and synthesize nanocomposite materials with exceptional performance for photocatalytic nitrogen fixation.

Keywords: Hydrogen bond; MOF; Nitrogen fixation; POM.