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 (VN) 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.