Bio-Inspired Iron-Based Carbonic Anhydrase Mimic for CO2 Hydration and Conversion

Abstract

CO2 conversion by stable, cost-effective carbonic anhydrase (CA)-like nanozymes emerges as an efficient and sustainable approach for CO2 fixation. In this work, a novel iron-based nanomaterial (Fe10@CN-Mg) was first reported to be a CA mimic, in which FeNx sites and Mg(OH)2 play a synergistically catalytic effect for CO2 conversion. Although this material has much lower metal content and cost, it has comparable kinetic constants (Km 6.37 mM and Vmax 30.74 mM/min) and a significantly higher CaCO3 formation rate (20.60 g·g–1·h–1, the quality of CaCO3 produced per hour per gram of the catalyst) than that of reported CA mimics. Fe10@CN-Mg is stable when processed at extreme pH, high temperature, organic solvents, and high ionic strength and also retains high activity after long storage times (two months) and seven cycles. In addition, Fe10@CN-Mg was successfully applied to convert CO2 into cyclic carbonates with high economic efficiency.