PHOTOCATALYTIC DECOMPOSITION OF WATER AND PHOTOCATALYTIC REDUCTION OF CARBON-DIOXIDE OVER ZRO2 CATALYST

It was found for the first time that the photocatalytic decomposition of pure water proceeded over ZrO2 powder without any loaded metals under UV irradiation. The rate of H-2 and 02 evolution increased upon addition of Na2CO3 and NaHCO3. Moreover, the evolution of CO (the photocatalytic reduction product of CO2) was observed from NaHCO3 solutions. The special characteristics of ZrO2 semiconductor are believed to be associated with its highly negative flat-band potential and wide bandgap. In the can of Cu(1 wt %)-ZrO2 catalyst suspended in NaHCO3 aqueous solution, the rates of ps evolutions were 19.5 mumol/h of H-2, 10.8 mumol/h of O2, and 2.5 mumol/h of CO. These mass balances were indicative of a stoichiometric and catalytic reaction.