Photoelectrocatalytic CO₂ reduction to C₁ and C₂ products via virus-like carrier transfer in Cu₂O-Au@TiO₂

The highly selective generation of products in the photoelectrocatalytic (PEC) CO₂ reduction reaction is significantly hindered by the complex multi-electron transfer process. In this work, we designed and synthesized a Cu₂O-Au@TiO₂ composite with a unique "core-shell-satellite" architecture via a facile wet-chemical approach. In this architecture, the Au nanocore strengthens visible-light harvesting through localized surface plasmon resonance (SPR) and injects hot electrons into the mesoporous TiO₂ shell, while the outer Cu₂O selectively exposes highly active (111) facets and establishes low-mismatch interfaces with TiO₂. This configuration promotes directional charge migration through virus-like synaptic channels, thereby accelerating multi-electron CO₂ reduction. The cooperative mechanism of SPR enhancement, crystallographic facet matching, and dynamic charge transfer enables efficient and selective conversion of CO₂ to C₂H₄. Under visible-light irradiation and applied potential, the optimized composite achieves a remarkable C₂H₄ yield of 174 ± 3.2 μmol·cm^-2·h^-1 with a sustained current density exceeding 75 mA·cm^-2. These findings highlight a rational structural design that synergistically couples plasmonic excitation with interfacial charge management, establishing a promising paradigm for developing high-performance photoelectrocatalytic systems toward solar-driven CO₂ reduction.