New Paper in ACS Appl. Energy Mater.

A new paper by Dan et al. just published in ACS Applied Energy Materials: A metal-free oxygenated covalent triazine 2-D photocatalyst works effectively from UV, visible to NIR spectrum for water oxidation apart from water reduction.

Solar-driven water splitting is highly desirable for hydrogen fuel production, particularly if water oxidation is effectively sustained in a complete cycle and/or by means of stable and efficient photocatalysts of main group elements, e.g. carbon and nitrogen. Despite extensive success on H2 production on polymer photocatalysts, polymers have met with very limited success for the rate-determining step of water splitting - water oxidation reaction, due to the extremely slow “four-hole” chemistry. Here, the synthesized metal-free oxygenated covalent triazine (OCT) is remarkably active for oxygen production in a wide operation window from UV to visible, and even to NIR (up to 800 nm), neatly matching the solar spectrum with an unprecedented external quantum efficiency (even 1% at 600 nm) apart from excellent activity for H2 production under full arc irradiation, a big step moving toward full solar spectrum water splitting. Experimental results and DFT calculations show that the oxygen incorporation not only narrows the band gap but also causes appropriate band-edge shifts. In the end, a controlled small amount of oxygen in the ionothermal reaction is found to be a promising, novel and facile way of achieving such oxygen incorporation. This discovery is a significant step towards both scientific understanding and practical development of metal-free photocatalysts for cost-effective water oxidation and hydrogen generation over a large spectral window.