Strong Internal Electric Field‐Driven S‐scheme CoAl‐LDH/ZrO ₂ Heterojunction for Enhanced Photocatalytic CO ₂ Reduction: Configuration, Performance, and Mechanism

Abstract The construction of S‐scheme heterojunctions with a strong internal electric field (IEF) is critical for enhancing photocatalytic performance. Herein, an S‐scheme heterojunction composed of CoAl‐LDH and ZrO ₂ (denoted as LZ‐60) is synthesized via a hydrothermal method. Under simulated solar irradiation, LZ‐60 exhibited a CO production rate of 562.545 µmol g ⁻¹ h ⁻¹ , which is five times higher than pristine CoAl‐LDH and 43 times higher than pristine ZrO ₂ . X‐ray photoelectron spectroscopy (XPS) revealed electron transfer from CoAl‐LDH to ZrO ₂ upon hybridization, generating an IEF at the interface. This electron transfer and IEF are further verified by density‐functional theory (DFT) calculations of work functions. Comparative XPS analysis before and after the photocatalytic reaction confirmed the S‐scheme charge transfer mechanism: the binding energies of Co and Al decreased, while Zr increased, indicating electron transfer from ZrO ₂ to CoAl‐LDH under light. Photoelectrochemical characterizations (PL, EIS) demonstrated enhanced charge separation in the heterojunction. In‐situ Fourier transform infrared spectroscopy identified CO* as the dominant intermediate, confirming high CO selectivity. The accelerated charge separation and strengthened redox capability synergistically contribute to the superior CO ₂ reduction performance of the S‐scheme LZ‐60 heterojunction. This work provides a valuable reference for designing efficient CO ₂ reduction photocatalysts.