Engineering Na-Au^{δ -} Interfaces for Enhancing Selective Methane Hydroxylation With O₂ via Controlled In Situ H₂O₂...

The selective oxidation of methane (CH₄) to value-added oxygenates (e.g., methanol, acetic acid) under mild conditions remains a pivotal yet formidable challenge in catalysis. Herein, we design Na-decorated Au nanoparticles supported on mordenite (MOR) nanosheets, which leverage electronic metal-support interactions to dynamically tune the electronic state and local microenvironment of the active sites for directional C─H activation under CH₄/CO/O₂/H₂O at 150° C. This catalyst affords near-100% selectivity toward hydroxylated oxygenates derived from CH₄ with a remarkable productivity of 2.02 mmol·g_cat ^-1·h^-1, outperforming most reported catalysts under comparable conditions. In situ spectroscopic studies and density functional theory (DFT) calculations reveal that Na-induced electronic modulation creates a unique Na-Au^{δ -} interfacial structure, driving the Au species into an electron-deficient state that boosts the oxygenate formation rate by more than an order of magnitude compared to the pristine Au^δ- sites. The Na-Au^δ- interface enhances catalysis by enabling accelerated in -situ H₂O₂ generation and concurrent C─H bond activation, while avoiding methanol overoxidation, thereby boosting overall catalytic performance. This work deciphers the dynamic role of in situ generated H₂O₂ in methane activation under mild conditions, and establishes electronic microenvironment engineering as a powerful strategy for the selective and controllable oxidation valorization of methane.