Catalytic oxidation properties of 3D printed ceramics with Bouligand structures

Bouligand structure composed of twist-aligned nanofiber lamina as one typical biological skeleton is widely presented in various organism. Inspired by this, a strategy was proposed by coupling a novel method of 3D printing with surface modification, attempting to build the programmable helicoidal catalytic ceramics and then improving the catalytic performance. In this work, the biomimetic Bouligand architectures with different pitch angles (α), where the pitch angle is defined as the rotational angle of two adjacent twisted layer filaments, were built. Typically, the construction of bioinspired helicoidal catalytic ceramics with Bouligand structure can be divided into two steps, including the 3D printing of unidirectionally aligning ceramic filaments helical stacked helicoidal Al2O3 ceramics, and the surface functionalization of platinum (Pt) catalysts. To this end, we designed and fabricated several helicoidal catalytic ceramics with pitch angles (α) of 30°, 45°, 60°, and 90° for exploring the catalytic performances of toluene vapor, and the acquired corresponding toluene conversions at 200 °C were 92.51%, 92.46%, 90.67%, and 78.51%, respectively. Furthermore, as an optimal twisted helicoidal catalytic ceramic device rotated from 0° to 180° with a pitch angle of 30°, the conversion of toluene at 200 °C can reach 95.52%, and exhibited excellent catalytic activity, favorable repeatability, and superior water resistance in the process of toluene oxidation. Thus, the prepared helicoidal catalytic ceramic was employed to transform the airflow direction, thereby prolonging the contact time between the gas and the catalyst for improving the catalytic efficiency. Overall, the simple yet efficient method for achieving tailored catalytic performance by controlling the pitch angles, dimensions, as well as the structural motifs, that can provide valuable ideas and revelations for developing light-structure catalytic materials in the future.