Printable Newtonian fluid photocatalysts for scale-up solar CO2 conversion

Photocatalysts are usually in powder form, which makes it difficult to expand the scale of photocatalysis. Here, we report a Newtonian fluid photocatalyst, which consists of an internal nano-hollow imidazole framework and an external light-excitable liquid chain striking a pose on the stage. Due to the intermolecular interaction at the solid-liquid interface and significant steric hindrance effect, the Newtonian fluid catalyst with higher surface tension can firmly adhere to different kinds of scaffolds via simple printing, such as curved surfaces, inclined walls, and grids. In addition to the easier scale-up, the pore structure of frameworks favors faster CO2 mass transfer, and the liquid chain with a co-catalytic effect serves as the electron donor for efficient CO2 photoreduction. In this work, the Newtonian fluid photocatalyst achieves a 57.8-fold increase in CO overflow efficiency (100% selectivity), and this universal synthesis method can convert common organic/inorganic photocatalysts into similar Newtonian fluid photocatalysts. The Newtonian fluid photocatalyst composed of imidazole framework and light-excitable liquid chain can be firmly attached to different types of carriers through printing for easier photocatalytic scaling up and more stable CO2 photoreduction.