Carboxyl hydrogel particle film as a proton source for electrode surface modification

• A hydrogel particle film-coated metallic cavity electrode was fabricated.
• Peak potential of dissociated H+ related to electrode surface structure.
• The particle film acted as a proton source under neutral conditions of bulk.

Uniformly sized poly(N-isopropylacrylamide-co-acrylic acid) (NIPA/AA) hydrogel particles were synthesized as a solid-acid for electrode surface modification. Voltammograms of the NIPA/AA particle film-coated platinum electrodes showed the reduction of hydrogen ions which were supplied from the dissociation of carboxyl groups of the absorbed NIPA/AA particles. The reduction peak potentials at the particle film-coated cavity platinum electrode were observed around − 0.38 V. Compared with that observed at flat platinum electrode, the peak potentials were shifted in the positive direction by 0.19 V. The peak currents were increased with increase in the amount of immobilized particle. The particle film worked as a source of supply of hydrogen ions for the electrochemical reduction of 1,4-naphthoquinone. The electrode surface pH was controlled to be 4.5 by NIPA/AA particle film in the neutral solution.

Figure optionsDownload as PowerPoint slide