Photocatalytic syngas production using conjugated organic polymers

Abstract

A range of linear conjugated polymers is reported that promote photocatalytic CO₂ reduction in water with a sacrificial hole-scavenger. Two photocatalysts containing dibenzo[b,d]thiophene sulfone were found to be the most active materials. A dibenzo[b,d]thiophene sulfone co-polymer with phenylene (P7) had the highest rate for producing CO, but also for the co-evolution of H₂. The homopolymer of dibenzo[b,d]thiophene sulfone was found to be less active for CO production, but had a higher H₂ production rate, which is explained by changes in the driving-force favouring proton reduction. The co-evolution of hydrogen is facilitated by residual palladium from the material synthesis. By varying the amount of palladium in the photocatalyst, syngas can be obtained with varying ratios of H₂ to CO.