Nitrogen Containing Linear Poly(phenylene) Derivatives for Photo-catalytic Hydrogen Evolution from Water

Here we study how the introduction of nitrogen into poly(p-phenylene) type materials affects their ability to act as hydrogen evolution photocatalysts. Direct photocatalytic water splitting is an attractive strategy for clean energy production, but understanding which material properties are important, how they interplay, and how they can be influenced through doping remains a significant challenge, especially for polymers. Using a combined experimental and computational approach, we demonstrate that introducing nitrogen in conjugated polymers results in either materials that absorb significantly more visible light but worse predicted driving force for water/sacrificial electron donor oxidation, or materials with an improved driving force that absorb relatively less visible light. The latter materials are found to be much more active and the former much less. The trade-off between properties highlights that the optimization of a single property in isolation is a poor strategy for improving the overall activity of materials.