Tandem design on electrocatalysts and reactors for electrochemical CO2 reduction

Electrochemical CO2 reduction (ECR) driven by green electricity represents a promising strategy for CO2 mitigation and utilization by producing fuels and chemicals. Tandem strategy based on multifunctional tandem catalysts or cascade reactors enables deep CO2 reduction to high-value multi-carbon products. Nevertheless, it is challenging to precisely regulate the multi-step reaction pathways toward efficient CO2 conversion. A comprehensive understanding of the tandem reaction mechanisms is crucial for guiding the rational design of advanced catalysts and reactor systems to address these challenges.

This review systematically elucidates the fundamental principles of tandem catalysis, presenting design strategies for multifunctional catalysts or cascade reactors to achieve hierarchical reaction coupling. Subsequently, it critically examines cutting-edge advancements in multiscale tandem methodologies: (1) At the microscale, synergistic interactions between distinct active sites within multifunctional catalysts are dissected, emphasizing precise compositional engineering to optimize electron/proton transfer and intermediate transport for enhanced C2+ product selectivity. (2) At the mesoscale, customized composite catalysts with spatially orchestrated reaction pathways are analyzed, particularly focused on hydrodynamic modulation through tandem electrode assemblies. (3) At the macroscale, cascade reactor architectures are innovatively designed, integrating system-level optimization of catalyst configurations with industrial-scale CO2 electrolysis to maximize overall conversion efficiency.

The concluding section highlights pioneering methodologies combining operando X-ray absorption spectroscopy (XAS), scanning tunneling microscopy (STM), and machine learning-aided theoretical computations. This multidisciplinary approach elucidates mechanistic insights into tandem catalytic cycles, establishes a dynamic reaction pathway database for reaction feasibility prediction, and accelerates the discovery of high-performance catalysts, thereby advancing T-ECR technology toward practical implementation. The results were published in Chinese Journal of Catalysis (DOI:10.1016/S1872-2067(24)60209-3) 

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