Hydroxyl Groups in Hexagonal Boron Nitride Enhance the Performance of Plasma-Catalyzed CH4 and H2O Conversion to Methanol

Nonthermal plasma (NTP) can convert CH₄/H₂O to high-value oxygen-containing chemicals (e.g., CH₃OH) under mild conditions, but controlling product selectivity in this process remains a major challenge. Herein, a boron hydroxyl (B–OH)-rich catalyst (hereafter named BN/H₂O₂) was prepared via H₂O₂-assisted ball milling and found to regulate the yield and selectivity of the conversion of CH₄/H₂O to oxygen-containing compounds in an NTP reactor. A CH₃OH yield of 1.04 mmol/h and a total carbon selectivity of 21.7% were achieved. BN/H₂O₂ showed approximately 2.6 and 1.5 times higher CH₃OH yield and total carbon selectivity, respectively, than the hexagonal boron nitride catalyst. The results of sequential experiments and theoretical calculations indicated that the B–OH site at the nitrogen defect (V_N) promoted the directed conversion of •CH₃ to CH₃OH via the Eley–Rideal mechanism, thereby enhancing the selectivity and yield of the conversion of CH₄/H₂O to CH₃OH.