Bifunctional reduced graphene oxide/polyelectrolyte/NiFe layered double hydroxide composites for efficient catalyzed dephosphorylation and 4-nitrophenol reduction

Dephosphorylation that separates phosphate groups from substrates is a significant reaction for both living organisms and environmental protection. Meanwhile, 4-nitrophenol (4-NP) is known to be a popular organic compound used for pesticides production, which is genotoxic and carcinogenic to humans and animals. Herein, we have developed a bifunctional catalyst that can be used for simultaneous dephosphorylation and 4-nitrophenol (4-NP) reduction when para-nitrophenyl phosphate (p-NPP) serves as the model compound. This bifunctional catalyst was obtained by in-situ growth of NiFe layered double hydroxide on the reduced graphene oxide/polyelectrolytes assembly nanolayers (denoted as rGP 3.5 /NiFe LDH). The results demonstrate that the rGP 3.5 /NiFe LDH can activate dephosphorylation of p-NPP at 20 °C and the catalytic efficiency increases significantly with increasing temperature in the range of 20 °C to 90 °C. Moreover, by-product 4-NP formed through p-NPP dephosphorylation is further fully converted to 4-aminophenol by the rGP 3.5 /NiFe LDH within 15 min. As far as we know, this is the first example for both dephosphorylation and 4-NP reduction through NiFe LDH as bifunctional catalysts, which paves the way for the development of multiple potential applications for NiFe LDH.