Wang Yansu, Suo Yujun, Lv Xianwei, Wang Zheng, Yuan Zhong-Yong
Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), School of Materials Science and Engineering, Nankai University, Tianjin 300350, China.
State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University, Yinchuan 750021, Ningxia, China.
J Colloid Interface Sci. 2021 Jul;593:304-314. doi: 10.1016/j.jcis.2021.02.129. Epub 2021 Mar 9.
Ga-based catalysts are promising for use in propane dehydrogenation (PDH) because of the relatively superior activity, but the conventional Ga-based catalysts usually suffer from serious deactivation and unsatisfactory propene selectivity. Here, ultrafine bimetallic Ga-Pt nanocatalysts encapsulated into silicalite-1 (S-1) zeolites (GaPt@S-1) were synthesized by a facile ligand-protected direct H-reduction method. It is indicated that this catalyst is composed of confined ultra-small GaPt alloy nanoclusters and a part of isolated tetrahedral coordination of Ga species. The confined GaPt alloy nanoclusters are the active sites for PDH reaction, and their high electron density could boost the desorption of products, resulting in a high propene selectivity of 92.1% and propene formation rate of 20.5 mol g h at 600 °C. Moreover, no obvious deactivation was observed over GaPt@S-1 catalyst even after 24 h on stream at 600 °C, affording an extremely low deactivation constant of 0.0068 h, which is much lower than that of the conventional Ga-based catalysts. Notably, the restriction of the zeolite can enhance the regeneration stability of the catalyst, and the catalytic activity kept unchanged after four consecutive cycles.
基于镓的催化剂因其相对优异的活性而有望用于丙烷脱氢（PDH），但传统的基于镓的催化剂通常会严重失活且丙烯选择性不尽人意。在此，通过一种简便的配体保护直接氢还原法合成了封装在硅沸石-1（S-1）分子筛中的超细双金属镓-铂纳米催化剂（GaPt@S-1）。结果表明，该催化剂由受限的超小GaPt合金纳米团簇和一部分孤立的四面体配位镓物种组成。受限的GaPt合金纳米团簇是PDH反应的活性位点，其高电子密度可促进产物解吸，在600℃时丙烯选择性高达92.1%，丙烯生成速率为20.5 mol g⁻¹ h⁻¹。此外，即使在600℃下连续运行24小时后，GaPt@S-1催化剂也未观察到明显失活，失活常数极低，为0.0068 h⁻¹，远低于传统的基于镓的催化剂。值得注意的是，沸石的限制作用可增强催化剂的再生稳定性，连续四个循环后催化活性保持不变。
