Pulsed-Laser-Engineered Cu Single Atoms in δ-Bi2O3 Nanosheets for Efficient Formate-Producing Zn-CO2 Batteries.

Herein, we report a pulsed laser irradiation in liquid (PLIL) strategy that concurrently induces phase transformation, morphological reconstruction, and single-atom stabilization in bismuth oxide (Bi2O3) for efficient carbon-dioxide reduction reaction (CO2RR). PLIL transforms α-Bi2O3 microrods to δ-Bi2O3 nanosheets, while simultaneous anchoring atomically dispersed Cu sites within the δ-Bi2O3 lattice. The CO2RR activity of the PLIL-derived δ-Bi2O3 nanosheets substantially exceeds that of α-Bi2O3 microrods and is further improved in Cu single-atom-stabilized δ-Bi2O3 (Cu SA/δ-Bi2O3) nanosheets, which deliver a high Faradaic efficiency (93.55%) with a formate yield rate of 210 µM·h-1·cm-2 at -1.0 V (versus the reversible hydrogen electrode). The key surface intermediates, identified using situ Raman and ex situ Fourier-transform infrared spectroscopy, confirm the stabilization of *OCHO species during formate formation. Theoretical calculations reveal that Cu single-atom incorporation electronically modulates the δ-Bi2O3 matrix, optimizing the intermediate adsorption energies and lowering the reaction barrier of the CO2-to-formate pathway. Furthermore, a Zn-CO2 battery with a Cu SA/δ-Bi2O3 cathode delivers an output voltage of 1.74 V and converts CO2 to formate while generating electricity for over 300 h of stable operation. The Zn-CO2 battery successfully powers light-emitting diodes and a digital clock, underscoring its potential in real-world energy-carbon coupling applications.