Facile Synthesis and Integration of Polyvinyl Alcohol Sponge-Supported Metal Nanocatalysts on a Microfluidic Chip enable a New Continuous Flow Multi-Reactor Nanocatalysis Platform for High Efficiency and Reusability Catalysis

A new polyvinyl alcohol (PVA) sponge-supported nanocatalysis platform on a continuous-flow microfluidic multi-reactor device was constructed for high-efficiency and high-reusability catalytic degradation of environmental pollutants. PVA sponge-supported metal nanoparticles catalysts (MNPs/PVA) were prepared by a simple improved impregnation self-assembly method, without any complicated surface modification. The MNPs/PVA catalysts were further integrated on a multi-reactor microfluidic device to form a continuous flow (CF) reactor platform (MNPs/PVA/chip) for simultaneous catalytic degradation of pollutants with two different nanocatalysts. After condition and catalyst optimizations, the catalytic activities of AuNPs/PVA and CoNPs/PVA were evaluated on this continuous flow microfluidic multi-reactor platform, by using <i>p</i>-nitrophenol (4-NP) as a model organic pollutant. Both catalysts exhibited outstanding catalytic efficiency (e.g., 100% for fresh catalysts) and the strong interactions between MNPs and PVA ensured high reusability (e.g., &gt; 20 cycles). After 20 cycles of catalysis, the optimal catalyst AuNPs/PVA still maintained a high catalytic efficiency of 97.6%. Compared to AuNPs/PVA-5, the cost-effective CoNPs/PVA catalyst exhibited similar catalytic performance within the first 10 cycles, while AuNPs/PVA showed better stability for long-term use. Hence, this continuous flow catalytic platform that combines the advantages of porous material-supported nanocatalysts with microfluidic devices has tremendous potential for various cost-effective environmental research and practical applications.