Electron transfer-induced catalytic enhancement over bismuth nanoparticles supported by N-doped graphene

Catalytic reduction of toxic 4-nitrophenol (4-NP) to useful 4-aminphenol over appropriate nanocatalysts is environmentally desired. Herein, bismuth nanoparticles (NPs) supported by N-doped reduced graphene oxide (Bi/NG) and carbon black (Bi/C) have been synthesized using hydrazine as the reductant. The resulting Bi/NG shows a superior catalytic activity towards the reduction of 4-nitrophenol (4-NP) with a high normalized rate constant (32.1 min(-1).mg(-1)), which is 2.9 times and 18.5 times higher than that of Bi/C and unsupported Bi NPs, respectively. The 4-NP conversion is as high as 99.7% and the yield of 4-AP is estimated to be 99.4%. The electronic structure of Bi NPs is modified through the electron transfer from Bi NPs to NG nanosheets due to so-called strong metal/support interaction (SMSI) effect. Such electron transfer results in abundant adsorption of reactants and rapid generation of active H species, both of which account for the promising catalysis of Bi/NG. Catalyst reuse shows no apparent deactivation or poisoning during the catalytic and separation processes, exhibiting good recyclability and reusability. This work may shed light on the design of high-efficiency catalysts for the 4-NP reduction by virtue of the electronic modification between active metals and carbon-like support.