K. Djessas

Correlation between gap energy and photocatalytic efficiencies of nanocatalyst under solar irradiation conditions

The most commonly studied and best performing catalysts and catalyst/dopant pairs were used to obtain a panel representative of the response range reported in the literature. Experiments were conducted to assess the photocatalytic performance of the catalysts under controlled irradiation, i.e. simulated sunlight. Our aim is to discriminate catalyst performance according to the nature of the catalyst, the associated dopant, and the spectral domain considered. We opted to express the rates of photocatalytic degradation as a function not of time, as in the case classically found in the literature, but of the number of photons absorbed meaning usable by the catalyst to produce radicals. This mode of representation, expressing the degrading capacity as a function of the number of photons available, allows the comparison and photocatalytic performance assessment of catalysts irrespective of irradiation conditions. Our results show that a catalyst’s performance depends on its characteristics and on the spectral range considered. We found that the constants derived from the kinetics obtained as a function of the number of efficient photons highlighted a very strong dependence on the catalyst’s band gap.