pH-controlled electrocatalysis of amino acid based on electrospun cobalt nanoparticles-loaded carbon nanofibers

Carbon nanofibers (CNFs) decorated with cobalt nanoparticles (CoNPs) were synthesized by a two-step procedure consisting of electrospinning and thermal treatment. The CoNPs–CNFs hybrid materials were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction spectrum, which showed that the CoNPs were of the cubic phase and well dispersed on the surface of CNFs. The electrochemical behaviors and electrocatalytic performances towards the oxidation of the amino acids at the CoNPs–CNFs modified glassy carbon electrode (GCE) were evaluated. The results indicated that the CoNPs–CNFs showed good electrocatalytic activity towards the oxidation of cysteine and N-acetyl cysteine, and the current response of the CoNPs–CNFs/GCE was sensitive to pH of the electrolyte solution. The peak current was quite large at pH 13.0 but greatly suppressed at pH 7.5, suggesting that the electrode can realize pH-controlled oxidation of amino acids. The good catalytic activity, well conductivity and high stability made the CoNPs–CNFs promising materials for constructing an enzymeless sensor.