Photocatalytic Solar Hydrogen Peroxide Production on Donor+Acceptor Linear Polymer Semiconductor Powders...

Developing an artificial photosynthesis technology that converts earth-abundant resources into fuels using metal-free photocatalysts with water as an electron donor is challenging. A few active organic semiconductors require harsh synthesis conditions and expensive reagents. Here, we report that a 1,4-conjugated linear polymer, poly(2,3-dihydroxynaphthalene) [poly23DHN], synthesized by the polymerization of inexpensive 23DHN at room temperature, behaves as a heterogeneous catalyst for artificial photosynthesis of hydrogen peroxide (H₂O₂) in water with O₂. The polymer is soluble in polar organic solvents but insoluble in water. The insolubilization of the polymer leads to self-assembly of a hydroquinone-quinone donor+acceptor semiconducting architecture via H-bonding and π-stacking interactions. The formed powders catalyze water oxidation and O₂ reduction under visible light up to ∼700 nm. Photocatalyst sheets easily prepared by dropping a polymer-dissolved solution onto a substrate stably generate H₂O₂. This polymer design that creates semiconducting structure through spontaneous H-bonding and π-stacking offers a scalable, easy-to-handle, cost-effective approach for solar fuel generation.