Saelee Tinnakorn, Limsoonthakul Poonnapa, Aphichoksiri Phakaorn, Rittiruam Meena, Lerdpongsiripaisarn Mongkol, Miyake Takanori, Yamashita Hiromi, Mori Kohsuke, Kuwahara Yasutaka, Praserthdam Supareak, Praserthdam Piyasan
High-Performance Computing Unit (CECC-HCU), Centre of Excellence on Catalysis and Catalytic Reaction Engineering (CECC), Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand.
Centre of Excellence on Catalysis and Catalytic Reaction Engineering (CECC), Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand.
Sci Rep. 2021 Jan 12;11(1):530. doi: 10.1038/s41598-020-79764-3.
Biodiesel is of high interest due to increased demand for energy with the concern regarding more sustainable production processes. However, an inevitable by-product is glycerol. Hence, the conversion of this by-product to higher-value chemicals, especially 1,3-propanediol (1,3-PDO) via glycerol hydrogenolysis reaction, is one of the most effective pathways towards a profitable process. In general, this process is catalyzed by a highly active Pt-based catalyst supported on γ-AlO. However, its low 1,3-PDO selectivity and stability due to surface deactivation of such catalysts remained. This led to the surface modification by WO to improve both the selectivity by means of the increased Brønsted acidity and the stability in terms of Pt leaching-resistance. Hence, we applied experimental and density functional theory (DFT)-based techniques to study the fundamentals of how WO modified the catalytic performance in the Pt/γ-AlO catalyst and provided design guidelines. The effects of WO promoter on improved activity were due to the shifting of the total density of states towards the antibonding region evident by the total density of states (TDOS) profile. On the improved 1,3-PDO selectivity, the main reason was the increasing number of Brønsted acid sites due to the added WO promoter. Interestingly, the stability improvement was due to the strong metal-support interaction (SMSI) that occurred in the catalyst, like typical high leaching-resistant catalysts. Also, the observed strong metal-support-promoter interaction (SMSPI) is an additional effect preventing leaching. The SMSPI stemmed from additional bonding between the WO species and the Pt active site, which significantly strengthened Pt adsorption to support and a high electron transfer from both Pt and AlO to WO promoter. This suggested that the promising promoter for our reaction performed in the liquid phase would improve the stability if SMSI occurred, where the special case of the WO promoter would even highly improve the stability through SMSPI. Nevertheless, various promoters that can promote SMSPI need investigations.
由于对能源的需求增加以及对更可持续生产过程的关注，生物柴油备受关注。然而，甘油是不可避免的副产物。因此，通过甘油氢解反应将该副产物转化为高价值化学品，特别是1,3 - 丙二醇（1,3 - PDO），是实现盈利过程的最有效途径之一。一般来说，该过程由负载在γ - AlO上的高活性铂基催化剂催化。然而，由于此类催化剂的表面失活，其1,3 - PDO选择性和稳定性较低的问题依然存在。这导致通过WO进行表面改性，以通过增加布朗斯台德酸度来提高选择性，并在抗铂浸出方面提高稳定性。因此，我们应用实验和基于密度泛函理论（DFT）的技术来研究WO如何改变Pt/γ - AlO催化剂的催化性能的基本原理，并提供设计指导。WO助剂对活性提高的影响是由于态密度总量向反键区域的移动，这在态密度总量（TDOS）图中很明显。关于1,3 - PDO选择性的提高，主要原因是由于添加了WO助剂，布朗斯台德酸位点数量增加。有趣的是，稳定性的提高是由于催化剂中发生了强金属 - 载体相互作用（SMSI），就像典型的高抗浸出催化剂一样。此外，观察到的强金属 - 载体 - 助剂相互作用（SMSPI）是防止浸出的额外效应。SMSPI源于WO物种与Pt活性位点之间的额外键合，这显著增强了Pt对载体的吸附以及从Pt和AlO到WO助剂的高电子转移。这表明，如果发生SMSI，在我们的液相反应中有前景的助剂将提高稳定性，其中WO助剂的特殊情况甚至会通过SMSPI极大地提高稳定性。然而，各种能够促进SMSPI的助剂仍需研究。
