Facile synthesis of Zncluster/NG nanozymes mimicking carbonic anhydrase for CO2 capture

Abstract

The continued warming of the Earth caused by CO2 emissions and the limitations of current technologies have led to a demand for new green and non-polluting CO2 capture technologies. Carbonic anhydrase (CA) mimicking nanozymes are a promising pathway for developing such technologies, but their incorporation of the spatial structure of natural active sites into nanomaterials remains a challenge. Therefore, the development of novel CA-mimicking nanozymes and the expansion of bionanomaterials for CO2 capture technology are essential. In this work, a novel CA mimic using 2D nitrogen-doped graphene with Zn nanoclusters (Zncluster/NG) was designed. Through changing the pyrolysis conditions, such as atmosphere and temperature, the enzyme-mimicking activities of Zncluster/NG were rationally regulated. The regulation was ascribed to the fine tune surface properties and catalytic sites of Zncluster/NG nanozymes such Zn nanocluster size, Zn content, and specific surface area, leading to the highest CA-mimicking activity possible by Zncluster/NG-900–800NH3. Notably, the Zncluster/NG-900–800NH3 nanozyme was capable of surviving high temperatures and wide pH ranges, and showed 10 times higher catalytic activity at 75 °C than at room temperature. Finally, experiments and DFT calculations were utilized to verify the advantages and surface catalysis mechanisms of Zncluster/NG in CO2 capture based on mimicking carbonic anhydrase. This study provides a facile and reference strategy for the rational design of CA mimics and broadens the application of nanozymes in CO2 capture technology.