The hypothesis is that if protonation of the BT unit is involved in the photocatalytic reaction, it would be more likely to occur in the acidic condition. At the same time, we also checked the effect of Pd amount in PFBT polymers on photocatalysis at different pH since the amount of active site should have a large impact on catalytic activity. Two PFBT samples with different Pd amounts, 1000 ppm, and less than 10 ppm Pd (below the detection limit), were chosen in this study. The Pdots from two PFBT samples were prepared as similarly as possible and then the photocatalytic experiments were carried out at two conditions: 0.2 M ascorbic acid with pH 4 and 0.2 M DEA with pH of 13.5 (ca 11 vol% as compared to the 30 vol% used in the reference ) . Under these two reaction conditions, there is almost a ten orders of magnitude difference in proton concentration in the ascorbate condition (0.1 mM protons) as compared to that of the DEA condition (50 fM protons). pH difference between 13.5 (DEA) and 4 (ascorbic acid) also leads to a large difference in driving force of 0.56 V for proton reduction.