3D Printing of Artificial Leaf with Tunable Hierarchical Porosity for CO2 Photoreduction

The development of new pathways for 3D artificial photosynthetic systems (APS) with controllable architectures and tunable hierarchical porosity on a large scale is significant. Herein, we demonstrate a 3D printing approach for fabricating artificial microleaves with 3D architectures spanning orders of magnitude from nanometers to centimeters in a rapid, programmable, and scalable manner. TiO2-based inks served as a preliminary prototype, with surfactants and silica nanospheres incorporated for porosity modification. Thus, a TiO2-based ink is developed to allow for the fabrication of porosity-tunable hierarchical 3D architectures with high surface area (up to similar to 259 m(2)g(-1)) and structural integrity with well-designed patterns. The artificial microleaves have macropore architectures comparable to those of natural leaves, indicating their efficient mass transfer ability. Artificial photosynthesis via CO, reduction enhances CO and CH4 evolution on the 3D printed APS by up to 2-fold and 6-fold, respectively, compared with the levels observed for the corresponding powder counterparts. Furthermore, gas diffusion behaviors, closely related to the gas-phase reaction, are investigated by theoretical simulation to reveal the hierarchical structural effects on catalytic efficiency. The strategy is proven to be critical and demonstrates obvious advantages in the potential scale-up of 3D APS device manufacturing.