Charge‐Compensated Cation/Anion Codoping Stabilizes Orthorhombic WO 3 With Exposed (100) Facet for Enhanced CO 2 ‐to‐C 2 H 4 Photoreduction Selectivity

Photocatalytic CO 2 reduction to C 2 H 4 offers a sustainable route for hydrocarbon production but is hindered by poor selectivity and rapid charge recombination. Herein, we develop a Cu/S/N codoped orthorhombic WO 3 photocatalyst through a facile solvothermal strategy. The charge‐compensated cation/anion codoping simultaneously reduces oxygen vacancies, relieves lattice strain, stabilizes the metastable orthorhombic phase, and boosts carrier separation and interfacial charge transfer. Meanwhile, the preferentially exposed (100) facet provides an abundant unsaturated coordination microenvironment that promotes CO 2 adsorption and reduces the C─C coupling barrier, thereby synergistically driving C 2 H 4 formation. The optimal Cu/S/N‐WO 3 ‐5 achieves a C 2 H 4 yield 29.8‐fold and selectivity 1.75‐fold those of the pristine WO 3 within 4 h, respectively. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) identifies key intermediates and reveals three parallel C 2 H 4 generation pathways, namely *CO dimerization, *CHO‐mediated coupling, and *CH 2 direct dimerization. This work demonstrates that charge‐compensated codoping combined with crystal plane engineering offers a versatile approach for stabilizing metastable phases and steering product selectivity toward valuable multicarbon products in photocatalytic CO 2 reduction.