Feng Ningdong, Lin Huiwen, Song Hui, Yang Longxiao, Tang Daiming, Deng Feng, Ye Jinhua
State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, CAS Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China.
International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Ibaraki, Japan.
Nat Commun. 2021 Aug 2;12(1):4652. doi: 10.1038/s41467-021-24912-0.
The conversion of photocatalytic methane into methanol in high yield with selectivity remains a huge challenge due to unavoidable overoxidation. Here, the photocatalytic oxidation of CH into CHOH by O is carried out on Ag-decorated facet-dominated TiO. The {001}-dominated TiO shows a durable CHOH yield of 4.8 mmol g h and a selectivity of approximately 80%, which represent much higher values than those reported in recent studies and are better than those obtained for {101}-dominated TiO. Operando Fourier transform infrared spectroscopy, electron spin resonance, and nuclear magnetic resonance techniques are used to comprehensively clarify the underlying mechanism. The straightforward generation of oxygen vacancies on {001} by photoinduced holes plays a key role in avoiding the formation of •CH and •OH, which are the main factors leading to overoxidation and are generally formed on the {101} facet. The generation of oxygen vacancies on {001} results in distinct intermediates and reaction pathways (oxygen vacancy → Ti-O → Ti-OO-Ti and Ti-(OO) → Ti-O pairs), thus achieving high selectivity and yield for CH photooxidation into CHOH.
由于不可避免的过度氧化,将光催化甲烷高选择性地高产率转化为甲醇仍然是一个巨大的挑战。在此,通过O将CH光催化氧化为CHOH的反应在Ag修饰的晶面主导的TiO上进行。{001}主导的TiO表现出4.8 mmol g h的持久CHOH产率和约80%的选择性,这比最近研究报道的值高得多,且优于{101}主导的TiO所获得的值。采用原位傅里叶变换红外光谱、电子自旋共振和核磁共振技术全面阐明了潜在机制。光生空穴在{001}上直接产生氧空位在避免形成•CH和•OH方面起着关键作用,•CH和•OH是导致过度氧化的主要因素,通常在{101}晶面上形成。{001}上氧空位的产生导致了不同的中间体和反应途径(氧空位→Ti-O→Ti-OO-Ti和Ti-(OO)→Ti-O对),从而实现了CH光氧化为CHOH的高选择性和高产率。