A highly efficient thermo responsive palladium nanoparticles incorporated guar gum hydrogel for effective catalytic reactions

Baobin Wang; Lei Dai; Guihua Yang; Guida Bendrich; Yonghao Ni; Guigan Fang

doi:10.1016/j.carbpol.2019.115289

A highly efficient thermo responsive palladium nanoparticles incorporated guar gum hydrogel for effective catalytic reactions

Carbohydr Polym. 2019 Dec 15:226:115289. doi: 10.1016/j.carbpol.2019.115289. Epub 2019 Sep 3.

Authors

Baobin Wang¹, Lei Dai², Guihua Yang³, Guida Bendrich⁴, Yonghao Ni⁵, Guigan Fang⁶

Affiliations

¹ College of Light Industry Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China; Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada.
² Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada; College of Bioresources Chemical and Materials Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China.
³ Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada; State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China.
⁴ Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada.
⁵ Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada. Electronic address: yonghao@unb.ca.
⁶ College of Light Industry Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, China. Electronic address: fangguigan@icifp.cn.

PMID: 31582067
DOI: 10.1016/j.carbpol.2019.115289

Abstract

Hydrogel, especially stimuli responsive hydrogel, has attracted enormous attention due to its unique properties for many applications. Herein, Pd NPs@ CNCs was firstly attained by in situgeneration of Pd NPs onto CNCs, and subsequently incorporated into guar gum-based hydrogel, so that a thermo responsive Pd NPs@ CNCs/ guar gum hydrogel catalytic system was obtained. The sol-gel transition was achieved viaa simple heating/cooling cycle: a sol state was obtained above 70 °C, allowing the catalytic reaction; a gel state was attained below 20 °C, allowing the reuse/ recycling of the Pd NPs. Pd NPs were formed by in situ reduction of PdCl₂ in the presence of CNCs so that Pd NPs were loaded onto CNCs surfaces. CNCs acted as stabilizers for the Pd NPs. The TEM image showed that the average size of Pd NPs is ˜3 nm. Subsequently, the Pd NPs@ CNCs composites were loaded into the guar gum hydrogel, based on the boron crosslinking chemistry. The hydrogel exhibited rapid sol-gel transition process upon heating (70 °C) and cooling (20 °C) cycles. The Pd NPs loaded sol-gel transition concept was subsequently applied to the Suzuki coupling reactions between aryl bromides and phenyl boronic acids, and a highly efficient catalytic performance (over 85% yield within 2 h) was obtained. The reuse/recycling of the thermo responsive Pd NPs@ CNCs/guar gum hydrogel catalyst system was investigated. This novel Pd NPs loaded thermo-responsive sol-gel transition concept is a promising new catalytic system.

Keywords: Catalysis; Guar gum; Hydrogel; Palladium; Sol gel; Thermo responsive.