**5. References**


cost of the performance because Pd and Ag are much cheaper than Pt. Further cost reduction will be dependent up the advance of the non-noble catalysts for the methanol

Increasing temperature has been proven as an effective way to accelerate fuel cell reactions. To investigate the fuel cell reactions in the intermediate temperature of 80 to 200 °C, we have developed a pressurized electrochemical cell based on a modified commercial Parr autoclave which can be pressurized up to 2000 psi. In this electrochemical cell, aqueous electrolyte solutions and liquid fuels can exist in their liquid forms in the intermediatetemperature range at varying balance pressure. This makes the investigations of intermediate-temperature fuel cell electrocatalysis possible. To further address experimental challenges, we have evaluated three kinds of Ag-based electrodes as an internal reference electrode in basic media and have found that the Ag/AgCl electrode could act as the internal reference electrode with satisfactory stability. To facilitate the investigations of the fuel cell reactions on high-surface-area electrocatalysts, a powder-rubbing procedure has been used to mechanically deposit the electrocatalysts onto a gold substrate of 0.5 mm in diameter. Based upon these efforts, well-developed cyclic voltammograms and chronoamperograms for the electrochemical methanol oxidation and oxygen reduction in

It is encouragingly found that the methanol electrooxidation in alkaline media on highsurface-area Pt and Pd electrodes can be substantially accelerated by increasing temperature, characterized by obvious decrease in the onset overpotential with increasing temperature. Moreover, CO could be oxidized at lower onset potentials than methanol in the intermediate temperature range under similar conditions. This strongly indicates that CO is no longer a poison limiting the methanol oxidation. Replacement of Pt with Pd produces no substantial decrease in the activity towards the methanol oxidation. For the electrochemical oxygen reduction, silver demonstrates a high activity in the intermediate temperature range which is comparable to that of high surface area Pt. This indicates the possibility of using non-Pt catalysts in intermediate-temperature alkaline methanol fuel cells. Our preliminary fuel cell studies demonstrate the high performance of intermediate-

Yu, H., Scott, K. & Reeve, W. (2003). A Study of the Anodic Oxidation of Methanol on Pt in

Prabhuram, J. & Manoharan, R. (1998). Investigation of Methanol Oxidation on

Dillon, R., Srinivasan, S., Aricò, S. & Antonucci, V. (2004). International Activities in DMFC

*Power Sources*, Vol.74, No.1, (July 1998), pp. 54-61, ISSN: 03787753

Vol.127, No. 1-2, (March 2004), pp. 112-126, ISSN: 03787753

Alkaline Solutions. *Journal of Electroanalytical Chemistry*, Vol.547, No.1, (April 2003),

Unsupported Platinum Electrodes in Strong Alkali and Strong Acid. *Journal of* 

R&D: Status of Technologies and Potential Applications. *Journal of Power Sources*,

the intermediate temperature range have been obtained.

temperature alkaline methanol fuel cell with Pt and non-Pt catalysts.

oxidation and the *orr*.

**4. Conclusion** 

**5. References** 

pp. 17-24, ISSN: 00220728


**8** 

*1Russia 2Japan* 

**Electrochemical Cells with Multilayer Functional** 

*2Advanced Manufacturing Research Institute, National Institute of Advanced Industrial* 

Striking progress has recently been made in understanding the central role of nitrogen oxide radicals, NOx, in atmospheric processes (Lerdau et al., 2000). NOx is implicated in the formation of acid rain and a tropospheric ozone (the principal toxic component of smog and a greenhouse gas) (Finlayson-Pitts, B.J. & Pitts, J.N., 1997; Lerdau et al., 2000). The major known source of NOx is fuel combustion and biomass burning. Air pollution by nitrogen oxides (NO*x*) in combustion waste causes serious environmental problems in urban areas. The reduction of nitrogen oxide emissions has become one of the greatest challenges in environment protection (Libby, 1971; Nishihata et al., 2002). This is why the different methods of NOx decomposition are intensely studied by numerous groups from academic

The main activities of scientific groups working in the field of NO decomposition are concentrated on the reduction of the NOx in the presence of NH3, CO, H2 or hydrocarbons. These scientific groups have been tested a large number of categories of catalysts with a different ways of NO decomposition reactions. The main directions of the research can be

**First,** the selective catalytic reduction of NO with ammonia, typical for chemical industrial plants and stationary power stations (Bosch & Janssen, 1988; Janssen & Meijer, 1993). The main step is the reduction on NO or NO2 to N2 and H2O. Generally, liquid ammonia is

**Second,** the catalytic reduction of NO in the presence of CO and/or hydrogen. These reactions are typical for the automotive pollution control. The use of CO or H2 for catalytic reduction was one of the first possibilities investigated in view of eliminating NO from automotive exhaust gas (Baker & Doerr, 1964, 1965; Klimisch & Barnes, 1972; Nishihata et

as well as industrial research laboratories (Garin, 2001; Parvulescu et al., 1998).

injected in the residual gas before the catalytic reaction takes place.

4NO+4NH3+O2 4N2+6H2O

6NO+4NH3 5N2+6H2O

**1. Introduction** 

described as follows.

al., 2002; Roth & Doerr, 1961).

**Electrodes for NO Decomposition** 

*1Institute of Solid State Physic Russian Academy of Sciences, Chernogolovka,* 

*Science and Technology (AIST), Shimo-shidami, Moriyama-ku, Nagoya* 

Sergey Bredikhin1 and Masanobu Awano2

