Correlations between photosorption and photocatalytic activities of alkali metal halides

Photostimulated Reactions at the Surface of Wide Band-Gap Metal Oxides (ZrO2 and TiO2): Interdependence of Rates of Reactions on Pressure−Concentration and on Light Intensity

“…[e] ) k abs ΛFτ e ) RFτ e ) gτ e (8) [h] ) k abs ΛFτ h ) RFτ h ) gτ h (9) rate of generation of carriers and are the lifetimes of free electrons (eq 11) and free holes (eq 12) from the various channels of carrier trapping. In general, τ e and τ h are interdependent, vary with time because of carrier trapping by vacancies (see stages 3a and 3b) whose concentration is not stationary, and depend on light intensity.…”

“…There are several processes that are common to both photostimulated adsorption and photocatalysis: (i) light absorption, (ii) diffusion and drift of charge carriers toward the surface, (iii) recombination and trapping of charge carriers, (iv) formation of surface-active centers, and (v) interaction of surface carriers with adsorbed molecules. In particular, these common points between PhA and photocatalysis manifest themselves in numerous linear correlations between initial rates of PhA processes and rates of photocatalytic reactions on metal oxides , and on alkali halides …”

“…In particular, these common points between PhA and photocatalysis manifest themselves in numerous linear correlations between initial rates of PhA processes and rates of photocatalytic reactions on metal oxides 6,7 and on alkali halides. 8 Thus, a study of photostimulated adsorption processes could prove useful in understanding the mechanism of photoexcitation of solids as a first step of surface photochemical processes and photocatalysis. The main goal of the work presented here is a kinetic analysis and experimental verification of the PhA mechanism in which we examine different decay pathways of active surface centers.…”