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

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 center dot g-1 center dot 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.

Automated summary

Stable and cost-effective carbonic anhydrase (CA)-like nanozymes, such as Fe10@CN-Mg, are efficient and sustainable for CO2 fixation. Fe10@CN-Mg, a novel iron-based nanomaterial, acts as a CA mimic with FeNx sites and Mg(OH)2 synergistically catalyzing CO2 conversion. It shows comparable kinetic constants, higher CaCO3 formation rate, and remains stable and active under extreme conditions and long storage times. Fe10@CN-Mg has been successfully applied for CO2 conversion into cyclic carbonates with high economic efficiency.