Recent progress in rare earth element modulated electrocatalysts for CO₂ electroreduction

Electrocatalytic CO₂ reduction reaction (CO₂RR) represents a highly promising carbon-negative technology, capable of mitigating atmospheric CO₂ concentrations while simultaneously generating value-added chemicals. Rare earth (RE) elements have been extensively used to fabricate advanced electrocatalysts for enhancing the performance of CO₂RR due to their unique 4f electron configurations and redox characteristics. However, critical challenges of achieving precise modulation on CO₂ selectivity with RE elements and their mechanisms are still being pursued. This review systematically summarizes recent advances in RE-based electrocatalysts for selective conversion of CO₂ towards each C₁ (CO, HCOOH/HCOO⁻ and CH₄) or C₂₊ (C₂H₄, C₂H₅OH) products, and aims to construct the relationship between the RE-mediated structure and electrocatalytic performance. Primarily, the fundamental aspects of CO₂RR selectivity and RE characteristics are established. Subsequently, selective modulation mechanisms for specific CO₂RR product and corresponding RE-based catalysts are proposed and classified. We elucidate the synergistic modulation on CO₂ reduction pathway by RE elements unique physicochemical properties (including 4f-electron properties, larger atomic radius, oxygen affinity, and high-valence state) in critical reaction metrics: CO₂ activation, *CO adsorption energy, C–C coupling kinetics, electron/mass transport efficiency and long-term catalytic stability. Building on this foundation, atomic-level control over Cu/RE ratio governs the selective generation of C₁ versus C₂₊ products by modulating reaction pathways, while the intrinsic high-valence stability of RE effectively enhances catalytic durability. Finally, we outline the current challenges and future research directions for RE-mediated CO₂RR systems. This review will offer rational principles and deeper understanding for engineering RE-based electrocatalysts toward desired chemicals under industrial-scale CO₂RR.