Biological Electrochemical CO ₂ Reduction: From Molecular Mechanisms to Complex Hybrid Architectures

ABSTRACT

The integration of biological catalysis with electrochemical systems offers a powerful paradigm for sustainable carbon valorization, effectively bridging the “complexity gap” inherent to conventional abiotic catalysis. Enzymes and microorganisms exhibit high catalytic selectivity and metabolic versatility, enabling the direct synthesis of functionalized multi‐carbon products beyond simple C ₁ –C ₂ compounds while operating close to thermodynamic limits. In this review, we offer insights into the design principles of biologic electrochemical systems, ranging from molecular mechanisms to system‐level integration. We first examine enzymatic electrocatalysis, where protein film electrochemistry provides mechanistic insights into intrinsic kinetics and active‐site regulation, while direct and mediated electron transfer strategies provide complementary solutions to coupling enzymes with electrodes. We next discuss microbial electrosynthesis, detailing how extracellular electron transfer is coupled to intracellular metabolism for CO ₂ conversion into fuels and biopolymers. Finally, we highlight the emergence of hybrid electro–bio platforms that functionally decouple carbon activation from molecular construction via gaseous or liquid intermediates. By integrating recent advances, this review provides a framework for the rational design of next‐generation CO ₂ utilization technologies.