Graphene-based hydrogel with embedded gold nanoparticles as a recyclable catalyst for the degradation of 4-nitrophenol

Hydrogels have been utilized as a sort of scaffold in catalytic field since they can offer good accommodation for noble metal nanoparticles (NPs) to the preparation of recyclable catalysts. In this work, the poly(4-vinylpyridine) (P4VP) grafted graphene oxide (GO) was firstly synthesized through surface-initiated atom transfer radical polymerization (SI−ATRP). Then, a tough and self-healable composite hydrogel was fabricated by integration of the P4VP-grafted GO into poly(acrylic acid) (PAA) matrix through hierarchically hydrogen-bonding interactions and simultaneous in-situ growth of gold nanoparticles (AuNPs) in the hydrogel scaffold. The as-prepared AuNPs@GO-g-P4VP/PAA composite hydrogel possesses improved mechanical strength and integrity, and exhibits higher catalytic activity in the reductive degradation of 4-nitrophenol into 4-aminophenol than other reported AuNPs-loaded hydrogel catalysts. In addition, the self-healing composite hydrogel catalyst shows ease of separation as well as good reusability without obvious loss of catalytic activity. This work provides an attractive method for the synthesis of robust functional nanoparticle-embedded composite hydrogel for application in various fields.