Baiyang Yu, Lu Cheng, Jiaju Wu, Bing Yang, Hong Li, Jing Xu, Ying Zhang, Chengsi Pan, Xiao-Ming Cao, Yongfa Zhu and Yang Lou
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引用次数: 0
Abstract
Direct oxidation of methane (DOM) using molecular oxygen (O2) and hydrogen (H2) is currently considered to be triggered by in situ produced H2O2 or free hydroxyl radicals (˙OH). However, the role of the surface hydroxyl group in the DOM that is in situ formed from O2 and H2 has long been ignored. Herein, we provide experimental evidence that DOM using H2 and O2 over titanium silicate-supported single Pd atoms coated with an ultrathin N-doped carbon (Pd1/TS-1@CN) catalyst is dominated by a surface hydroxyl group instead of H2O2 or free ˙OH. Furthermore, the direct bonding between Pd atoms with the pyrrolic nitrogen of the coating layers reinforces the bonding strength of Pd1 and framework oxygen, forming a unique N1–Pd1–O2 configuration that considerably boosts the stability of isolated Pd active sites and their capability to stably generate a surface hydroxyl group from H2 and O2. Therefore, Pd1/TS-1@CN yields a liquid oxygenate productivity of 647 μmol gcat−1 h−1 with 100% selectivity at 15 °C and high stability over 30 cycles with no activity loss. Our findings regarding the catalytic role of the surface hydroxyl group in DOM and its stabilization strategy open up a new avenue for designing advanced catalysts for the DOM using O2 under mild reaction conditions.
期刊介绍:
Energy & Environmental Science, a peer-reviewed scientific journal, publishes original research and review articles covering interdisciplinary topics in the (bio)chemical and (bio)physical sciences, as well as chemical engineering disciplines. Published monthly by the Royal Society of Chemistry (RSC), a not-for-profit publisher, Energy & Environmental Science is recognized as a leading journal. It boasts an impressive impact factor of 8.500 as of 2009, ranking 8th among 140 journals in the category "Chemistry, Multidisciplinary," second among 71 journals in "Energy & Fuels," second among 128 journals in "Engineering, Chemical," and first among 181 scientific journals in "Environmental Sciences."
Energy & Environmental Science publishes various types of articles, including Research Papers (original scientific work), Review Articles, Perspectives, and Minireviews (feature review-type articles of broad interest), Communications (original scientific work of an urgent nature), Opinions (personal, often speculative viewpoints or hypotheses on current topics), and Analysis Articles (in-depth examination of energy-related issues).