Lu Juntao

Solid polymer electrolyte-based electrochemical oxygen sensor

Abstract An SPE (solid polymer electrolyte)-based solid-state electrochemical oxygen gas sensor is reported. A hydrophobic Teflon-bonded Pt back layer pressed on a piece of Nafion membrane serves as the working (sensing) electrode, with a diffusion-controlling capillary in front. The sensor exhibits fast response, small temperature coefficient and long-term stability.

THE GENERAL CHARACTERISTICS OF MICROELECTRODES OF ANY PLANAR GEOMETRY UNDER STEADY-STATE CONDITIONS

Abstract The general characteristics of microelectrodes of any planar geometry under steady-state conditions are discussed. The exact expression for reversible i-E waves is obtained. Irreversible and quasi-reversible processes are also discussed. The approximate expressions for the steady-state voltammetric curves of irreversible electrode reactions are derived by both “uniform surface concentration” and “uniform flux” approaches.

Study on response time of SPE carbon monoxide sensor

The influence of structural design and the parameters of the working electrode on the response time of a solid polymer electrolyte (SPE) carbon monoxide sensor has been studied. Results show that the response time is mainly determined by the RC time constant of the catalyst layer and also related with the working electrode potential.

Oxidation and adsorption of Co at Pt−Au-SPE electrodes

Pt−Au-SPE electrodes made by the successive chemical deposition of Au and Pt on Nafion membranes were tested and compared with the single metal-SPE electrodes for surface oxidation, CO adsorption and oxidation. Part of the surface of the binary metal electrodes behaves differently from either Au or Pt single metal-SPE electrode for COads oxidation, revealing surface modulation effects in the binary metal electrode. However, these mudulated surfaces have no appreciable contribution to the electrode activity for CO oxidation. The electrode activity for CO oxidation is mainly governed by the total Pt surface area of the binary electrodes. The predeposited Au was found to be favorable for higher dispersion of the successively deposited Pt.