Bifunctional Core–Shell Architecture of nFe 0 @CNT Enables Efficient Biocatalytic Reduction

ABSTRACT Typical biotic‐abiotic hybrid systems utilize external energy (e.g., light or electricity) to boost biocatalytic reduction reactions. In this study, we propose a bifunctional core–shell architecture (graphitized carbon‐coated nano iron, nFe 0 @CNT) to improve biocatalytic reduction performance without relying on external energy to deliver electrons into the cells. The carbon shell increased the substrate utilization rate by 87%, along with an increased pool of the intracellular electron carrier nicotinamide adenine dinucleotide (NADH). Concurrently, the nano iron core enhanced the activities of NADH dehydrogenase and functional enzymes by 66.5% and 69.3%, respectively, increasing the capacity for NADH utilization. This simultaneous enhancement of substrate utilization and enzyme activities markedly promoted bio‐denitrification and biosynthesis. Life cycle assessment and economic analysis demonstrate that this strategy yields lower environmental impacts relative to conventional strategies for enhancing biocatalysis, with carbon emissions reduced by 50.0%–86.0% and costs decreased by 79.2%–89.2%. This work provides a new paradigm for enhancing biocatalytic reduction by functional materials without external energy input.