However, a slight decrease of the p

However, a slight decrease of the production rates occurred throughout the whole process. The maximal production rates of CO and O 2 were found at 18 h to be 0.56 and 0.27 µmol·h -1 , respectively (Fig. S6). The recession of the photocatalytic yield rates may be due to oxidation of the products or formation of intermediates covering the surface active sites of photocatalysts.