Direct piezocatalytic conversion of methane into alcohols over hydroxyapatite

The cascading of methane valorization and methanol upgrade, both of which are important in C1 chemistry, becomes a promising strategy to fabricate value-added chemicals from methane directly. Reconciling the contradiction between the C‒H bond activation of methane and the over-oxidation susceptibility of methanol is critical but challenging. Herein, we report the piezocatalytic methane conversion over hydroxyapatite (HAp) under ultrasonic vibration at ambient conditions, obtaining alcohols as liquid products without any sign of CO or CO2. Mechanistic studies reveal that the piezocatalytic effect of HAp drives H2O and methane activation and supplies hydroxyl radical (·OH) to attack the methane C‒H bond, while the ultrasonic-induced negative surface charge (SC) promotes methanol dehydration into methyl carbene as a fascinating C1 building block to facilitate product upgrade into C2 and C3 alcohols. Attributing to the enriched SC which tunes the surface acid-base property, piezocatalysis presents a new approach for C‒C coupling.