Au Nanoparticles Loaded ZnGaAl‐Layered Double Hydroxides for Efficient Photocatalytic Methane Oxidative Coupling

Abstract Photocatalytic oxidative coupling of CH ₄ (OCM) is a promising CH ₄ conversion process with the assistance of O ₂ . Herein, the Au nanoparticles (10 nm) are loaded onto ZnGaAl‐layered double hydroxides (ZnGaAl‐LDH) via calcination‐reconstruction method followed by NaBH ₄ reduction. The resultant Au/ZnGaAl achieved a CH ₄ conversion rate of 47.1 mmol g ⁻¹ h ⁻¹ and an C ₂ H ₆ selectivity of 80%, which is five times higher than that of Au/ZnAl. Note that the Au/ZnGaAl exhibited the best catalytic activity for low‐temperature methane oxidative coupling (OCM) to date. Detailed experiments revealed that the incorporation of Ga promoted electron transfer from Zn to O, which increased the electron density around the oxygen vacancy (O _V ), thereby enhancing O ₂ activation capacity. Subsequently, the Au nanoparticles stabilized CH ₃ • radicals and promoted their coupling to form C ₂ H ₆ . Density functional theory (DFT) calculations showed that the introduction of Ga shifted the d‐band centers of Zn and Au in Au/ZnGaAl closer to the Fermi level, optimizing the electronic structure of Au/ZnGaAl and enhancing the coupling activity of CH ₃ • radicals on the Au nanoparticle. This work bridges the gap in improving the activity and stability of Zn‐based LDHs as low‐temperature OCM catalysts.