Sodium-tungsten-manganese supported on silica (Na-W-Mn/SiO₂) and hydroxyapatite (HAp) are representative catalysts for oxidative coupling of methane (OCM). In this work, the effect of the HAp doping in a Na-W-Mn/SiO₂ catalysts on the OCM performance was studied. To enhance the ethylene selectivity of the Na-W-Mn/SiO₂ catalyst, silica supports were coated with HAp containing hydroxyl and phosphate groups as oxygen species. A series of Na-W-Mn/xHAp_SiO₂ (x=1, 3, 5 and 7) catalysts with the different HAp coating cycles were prepared through the alternative soaking method, and X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that the amount of HAp doping was dependent on the HAp coating cycles. In addition, the change of oxygen species upon HAp doping was examined with X-ray photoelectron spectroscopy (XPS) and oxygen temperature-programmed desorption (O₂-TPD) techniques. With HAp doping, the increase of oxygen species assigned to metal oxide responsible for selective oxidation of methane to ethylene was observed in O 1s XPS spectra. In addition, weakly bound oxygen species were observed with the introduction of HAp doping in O₂-TPD profiles of prepared catalysts. The influence of these oxygen species on OCM catalytic performance was evaluated at an operating temperature of 775 °C and gas hourly space velocity of 18,000 ml/g_cat·h. The amount of HAp doping provided reactive oxygen species for oxidative dehydrogenation of ethane, which resulted in as much as 120% increase in C₂H₄/C₂H₆ ratio over the Na-W-Mn/3HAp_SiO₂ catalyst compared to the Na-W-Mn/SiO₂ catalyst.

负载在二氧化硅上的钠-钨-锰 (Na-W-Mn/SiO ₂ ) 和羟基磷灰石 (HAp) 是甲烷氧化偶联 (OCM) 的代表性催化剂。在这项工作中，研究了 HAp 掺杂在 Na-W-Mn/SiO ₂催化剂中对 OCM 性能的影响。为了提高 Na-W-Mn/SiO ₂催化剂的乙烯选择性，二氧化硅载体被包覆有含羟基和磷酸基团作为氧物种的 HAp。Na-W-Mn/xHAp_SiO _{2 系列}(x=1, 3, 5, 7)通过交替浸泡法制备了不同HAp包覆周期的催化剂，X射线衍射（XRD）和扫描电子显微镜（SEM）表明HAp掺杂量是依赖的在 HAp 涂层循环中。此外，使用 X 射线光电子能谱 (XPS) 和氧气程序升温脱附 (O ₂ -TPD) 技术检查了 HAp 掺杂后氧物质的变化。随着HAp掺杂，在O 1s XPS光谱中观察到分配给负责甲烷选择性氧化成乙烯的金属氧化物的氧种类增加。此外，在 O _{2 中}引入 HAp 掺杂后，观察到弱结合氧物种-制备的催化剂的TPD曲线。在 775 °C 的操作温度和 18,000 ml/g _cat ·h 的气时空速下评估这些氧物种对 OCM 催化性能的影响。HAp 的掺杂量为乙烷的氧化脱氢提供了活性氧物种，与 Na-W-Mn/3HAp_SiO ₂催化剂相比，C ₂ H ₄ /C ₂ H ₆比增加了 120% -W-Mn/SiO ₂催化剂。