State Key Laboratory of Heavy Oil Processing, China University of Petroleum , Qingdao, 266580, China.
ACS Appl Mater Interfaces. 2017 Sep 13;9(36):30711-30721. doi: 10.1021/acsami.7b09482. Epub 2017 Aug 28.
The reaction of isobutane over Ni/SiO catalyst changes from hydrogenolysis to dehydrogenation when Sn is introduced. The adsorption modes and energies of isobutane and isobutene over the Ni/SiO catalyst with and without Sn addition were determined by in situ FTIR and a novel transient response adsorption approach. In the absence of Sn, isobutane is adsorbed in a double-site mode with H atoms in two methyl groups of isobutane, facilitating hydrogenolysis of isobutane. After the addition of Sn, a single-site adsorption mode with the H atom in the methylidyne group is speculated instead, which is beneficial to the rupture of the C-H bond rather than the C-C bond. Moreover, the double-site adsorption mode of isobutene with the C═C bond and the H atom in a methyl group is turned into single-site mode with the C═C bond after the introduction of Sn. As for the adsorption energy of isobutene, the introduction of Sn leads to an obvious decrease from 74 to 50 kJ mol and facilitates the prompt desorption of isobutene, resulting in a high selectivity of 81.9 wt %.
当引入锡时，异丁烷在 Ni/SiO2 催化剂上的反应从氢解变为脱氢。通过原位 FTIR 和一种新的瞬态响应吸附方法，确定了添加和未添加 Sn 的 Ni/SiO2 催化剂上异丁烷和异丁烯的吸附模式和能量。在没有 Sn 的情况下，异丁烷以双位模式吸附，其中异丁烷的两个甲基中的 H 原子促进异丁烷的氢解。添加 Sn 后，推测会形成具有亚甲基 H 原子的单一位点吸附模式，这有利于 C-H 键而不是 C-C 键的断裂。此外，异丁烯的双键和一个甲基中的 H 原子的双位吸附模式在引入 Sn 后变为双键的单一位点模式。对于异丁烯的吸附能，引入 Sn 导致其从 74 kJ/mol 明显降低，促进了异丁烯的快速脱附，从而获得了 81.9 wt %的高选择性。
