(624a) the Micromixing Performance of Micro-Impinging Stream Reactors and Their Applications in Preparing High Performance Ultrafine Materials

Ultrafine materials have found wide applications because of their small size and big surface area. One of the key factors affecting the properties of the produced materials is the mixing performance of the synthesis equipment. The product quality of ultrafine materials prepared with conventional reactors such as stirred tank reactors (STR) is usually unsatisfactory due to their low mixing efficiency, especially at the micro-scale level; therefore, the synthesis of high performance ultrafine materials often requires complicated reactors with intensified micromixing.

For this purpose, micro-impinging stream reactors (MISR) with very simple structure were built to prepare high performance ultrafine materials. Intensified micromixing was achieved by the impinging streams within a micro-impinging domain inside the reactor under normal pressure; therefore, materials with a smaller particle size and much narrower size distribution could be easily formed even at very low temperatures with such a device. As two examples, ultrafine manganese dioxide and Ni-Co-O composite particles as supercapacitor materials were synthesized with MISR by co-precipitation at room temperature. The obtained samples have better morphologies, as well as higher specific capacitance (SC), than those prepared with STR. In addition, the effects of operating conditions and structure of MISR on the micromixing efficiency, the morphology and SC of the produced materials were also explored. It showed that MISR is a promising efficient and green process for the preparation of high performance ultrafine materials.