ELECTROCATALYSIS

Centre researchers are intensively studying the process of electrocatalysis. As oxidation and reduction can be carried out using only electrons as reagents, this field holds promise for the development of "green chemistry". Centre research focuses on two areas: thin film photo-electrocatalysis, and glassy metals.

Glassy Metals
Researchers hope to prepare new catalysts for electrochemical energy conversion in fuel cells, including binary alloys that combine platinum and metals from groups IV and V (e.g. Sn., Bi, Si, Ge, P). These alloys can be rapidly quenched to form thin layers. By avoiding immiscibility gaps and surface segregation that can limit catalytic performance, this process allows formation of compositionally uniform catalysts. The oxidation of hydrogen, carbon monoxide and methanol, and the reduction of oxygen on these amorphous alloys, is important in assessing their relative performance in fuel cell applications.

Metal Oxides
Titanium dioxide has found use as a photoelectrocatalyst in the oxidation of organic pollutants in ground water. Centre researchers are actively investigating the use of thin-film titanium dioxide as an alternative to powder-based preparations. They are preparing the active film on an inexpensive, inactive support using spray pyrolysis. Much of the work in this area has involved either titanium dioxide powder or pellets formed from the powder. Two key properties of the film are its electrical conductivity and its porosity. Conductivity is controlled by suitable doping, and high porosity has been attained by control of the spray pyrolysis parameters. Following preliminary studies by Pacific Technology showing that the activity of the first Guelph films was 87% of the best anatase TiO2 powder available, researchers are now studying ways to improve them.