H. Tada et al., The effect of nanometre-sized Au particle loading on TiO2 photocatalysed reduction of bis(2-dipyridyl)disulfide to 2-mercaptopyridine by H2O, PHYS CHEM P, 3(7), 2001, pp. 1376-1382
TiO2 photocatalysed reduction of bis(2-dipyridyl)disulfide (RSSR) to 2-merc
aptopyridine by H2O is enhanced significantly by incorporation of nanometre
-sized Au particles. The rate is strongly dependent on the amount of Au loa
ded (x wt.%), passing through a maximum at x similar to0.3, while it is alm
ost independent of the Au particle size in the 4.3-11 nm range. Comparison
of the effects of Au and Ag loading reveals that the rate constant of the A
u(0.25 wt.%)/TiO2 system is greater than that of the Ag(0.24 wt.%)/TiO2 sys
tem by a factor of 2.6 and the activation energy of the former is about two
-thirds that of the latter. The enhancing effect of the Au loading is discu
ssed in terms of kinetic and molecular orbital considerations.