Highly Selective Methane-to-Methanol Conversion Enabled by Bimetallic Nanoclusters Using Molecular Oxygen

Methane, the most stable alkane, is significantly more stable than its partial oxidation products. This renders the highly selective conversion of CH₄ to CH₃OH an extremely intractable challenge, especially when using molecular oxygen as the oxidant. In this work, we synthesized a bimetallic-modified zeolite composite catalyst (PdCo bimetallic nanoclusters supported on H-ZSM-5 molecular sieve, denoted as PdCo@H-ZSM-5) via a simple impregnation method. PdCo@H-ZSM-5 can efficiently activate H₂ and O₂ to highly selectively oxidize CH₄ to CH₃OH under mild conditions (70°C), achieving a remarkable CH₃OH yield of 2349 µmol g_cat ^-1 h^-1 (249 mmol g_Pd ^-1 h^-1). Significantly, PdCo@H-ZSM-5 is the sole catalyst reported to date that can achieve over 99% CH₃OH selectivity in the oxidation of CH₄ by molecular oxygen under mild conditions. This work is expected to inspire new technologies for industrial CH₄ to CH₃OH conversion, promoting more sustainable chemistry and engineering. Furthermore, the low-energy consumption, high-efficiency activated oxygen catalyst eliminates the necessity for transporting and storing highly concentrated hydrogen peroxide, serving as a foundation for other green oxidation reactions.