Similar experiment has been described in detail elsewhere [26].
The twin photoreactor system is shown in Scheme 1. At first, 0.15 g of Pt/CuAlGaO4 and 0.15 g of Pt/SrTiO3:Rh in 2 mM FeCl2 solution
while 0.30 g of commercial WO3 in 2 mM FeCl3 solution were
placed in the CO2-hydrogenation and the O2-generation compartment,
respectively. Nafion membrane was used to divide the two
compartments of a connected twin reactor. The solution with a
pH of 2.6 (adjusted by adding sulfuric acid) and a volume of
225 mL in each compartment of the twin reactor was stirred during
the reaction. Prior to conducting experiment, ultra-pure Ar
gas was bubbled through the solution in the O2-generation compartment
while either ultra-pure CO2, CO or mixture of CO2/CO
was bubbled through the solution in the CO2-hydrogenation compartment.
Artificial sunlight, which was provided by the 300-W
xenon lamp (Newport, USA) integrating with an AM1.5G filter,
was used as the light source in this study. The light intensity in
front of the twin reactor was approximately 90mWcm2, which
was similar to the power and spectral distribution of the sun at
48.5 zenith angle.