Luo Laihao, Luo Jie, Li Hongliang, Ren Fangning, Zhang Yifei, Liu Andong, Li Wei-Xue, Zeng Jie
Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, P. R. China.
Nat Commun. 2021 Feb 22;12(1):1218. doi: 10.1038/s41467-021-21482-z.
As a 100% atom-economy process, direct oxidation of methane into methanol remains as a grand challenge due to the dilemma between activation of methane and over-oxidation of methanol. Here, we report that water enabled mild oxidation of methane into methanol with >99% selectivity over Au single atoms on black phosphorus (Au/BP) nanosheets under light irradiation. The mass activity of Au/BP nanosheets reached 113.5 μmol g in water pressured with 33 bar of mixed gas (CH:O = 10:1) at 90 °C under light irradiation (1.2 W), while the activation energy was 43.4 kJ mol. Mechanistic studies revealed that water assisted the activation of O to generate reactive hydroxyl groups and •OH radicals under light irradiation. Hydroxyl groups reacted with methane at Au single atoms to form water and CH* species, followed by oxidation of CH* via •OH radicals into methanol. Considering the recycling of water during the whole process, we can also regard water as a catalyst.
作为一种100%原子经济的过程，由于甲烷活化和甲醇过度氧化之间的困境，将甲烷直接氧化为甲醇仍然是一个巨大的挑战。在此，我们报道了在光照下，水能够使甲烷在黑磷（Au/BP）纳米片上的金单原子上以>99%的选择性温和氧化为甲醇。在90°C、光照（1.2W）下，在33巴混合气体（CH:O = 10:1）压力的水中，Au/BP纳米片的质量活性达到113.5 μmol g，而活化能为43.4 kJ mol。机理研究表明，水在光照下协助O的活化以产生活性羟基和•OH自由基。羟基在金单原子处与甲烷反应形成水和CH物种，随后CH通过•OH自由基氧化为甲醇。考虑到整个过程中水的循环利用，我们也可以将水视为一种催化剂。
