What has not been reported previously in the literature is the
beneficial effect of Pt nanoparticles on the stability of the composite
(i.e., the oxygen vacancies). Two explanations present themselves:
(i) due to the presence of Pt particles on the Anatase
phase, less electrons are transferred to the Rutile phase, necessary
for oxygen reduction and reaction with the vacancies, and (ii) the
vicinity of the Pt particles to the vacancies on the Rutile phase prevents
re-oxidation by preferred oxygen adsorption (and reaction)
over these Pt nanoparticles. Currently, we have no preference for
one of these two options, and both might actually be relevant.