Celebrating TenYears of Covalent Organic Frameworks for Solar Energy Conversion: Past, Present and Future.

Abstract

Accelerated anthropogenic emission of greenhouse gases due to increasing energy demands has created a negative impact on our planet. Therefore, replacement of fossil by renewable energy resources has become of paramount interest. It is within this setting that organic photocatalysts have emerged as a new generation of earth-abundant catalysts for the conversion of solar radiation into chemical energy. In 2014, the first example of a covalent organic framework (COF) photocatalyst for the hydrogen evolution reaction has been reported by our group, which has not only marked the beginning of COF photocatalysis for solar fuel production, but also helped to accelerate research into "soft photocatalysis". In the last decade, significant progress has been made towards developing COFs as robust, molecularly precise platforms emulating artificial photosynthesis. This mini-review commemorates the 10th year anniversary of COF photocatalysis and gives a brief historical overview of the milestones in the field. We review milestones in the development of COFs for solar fuel production and related photocatalytic transformations, including hydrogen evolution, oxygen evolution, overall water splitting, CO2 reduction, N2 fixation, oxygen reduction and alcohol oxidation. We discuss lessons learnt for the design of structure-property-function relationships in COF photocatalysts, and future perspectives and challenges for the field.