Engineering Na–Au δ − Interfaces for Enhancing Selective Methane Hydroxylation With O 2 via Controlled In Situ H 2 O 2 Generation

ABSTRACT The selective oxidation of methane (CH 4 ) 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 CH 4 /CO/O 2 /H 2 O at 150° C. This catalyst affords near‐100% selectivity toward hydroxylated oxygenates derived from CH 4 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 H 2 O 2 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 H 2 O 2 in methane activation under mild conditions, and establishes electronic microenvironment engineering as a powerful strategy for the selective and controllable oxidation valorization of methane.