Study on the active sites and poisoning of Pt catalysts for acetylene hydrochlorination

Wang, Yanlin 2023. Study on the active sites and poisoning of Pt catalysts for acetylene hydrochlorination. PhD Thesis, Cardiff University. Item availability restricted.

	PDF - Accepted Post-Print Version Restricted to Repository staff only until 29 May 2025 due to copyright restrictions. Download (6MB)
	PDF (Cardiff University Electronic Publication Form) - Supplemental Material Restricted to Repository staff only Download (131kB)

Abstract

Vinyl chloride is extensively used in the production of poly vinyl chloride (PVC), which is one of the 5 most popular plastics worldwide. Traditionally, supported HgCl2 catalyst is applied in the industrial production of vinyl chloride monomer (VCM) via the acetylene hydrochlorination route. However, the active component HgCl2 is volatile, resulting in a short lifetime of the catalyst and tremendous hazards brought to the environment and mankind. After the Minamata Convention on Mercury was signed by nearly 140 countries, the manufacture, import, and export of products containing mercury will be prohibited. Finding alternatives to Hg catalysts and ultimately replacing them became an urgent task. Among the non-Hg catalysts, Au catalyst is the most promising candidate for future industrial application. However, due to the high cost of Au catalyst, other alternatives, including non-metal catalysts, were also paid attention to. Pt catalysts is predicted to be highly active in actylene hydrochlorinartion reaction, and the price of Pt is cheaper than that of Au by 40%. However, not like the other kinds of transition metal catalysts, Pt catalysts haven not been extensively studied. In this work, a series of single-atom Pt catalysts were prepared via a simple wet impregnation method. Combining distinguishable catalytic performance of the catalysts with characterizations including XPS and XAS, a general evolution of Pt species in the induction period of acetylene hydrochlorination reaction was revealed. The content of PtClx(II) was proposed as one of the main activity descriptors. Meanwhile, principles in selecting appropriate Pt complexes as precursors were raised. Regarding the catalyst poisoning of Pt catalysts caused by trace impurities in C2H2 feeds, it was discovered that the poisoning can take place over a wide range of reaction temperature but can be reversed when the poisons Abstract II are removed from the system. A mechanism of poisoning was proposed by analyzing the characteristics shown by Pt catalysts in poisoned reactions and characterizations. The facile preparation of Pt catalysts with highly dispersed single Pt atoms, the study on the evolution of active sites in the reaction, and the understanding of catalyst poisoning which is highly possible for Pt catalysts to meet in future industrial applications, can help build up a more promising future for the industrial application of Pt catalysts for acetylene hydrochlorination. Keywords: acetylene hydrochlorination, Pt, active sites, catalyst poisoning

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Chemistry
Funders:	Chinese Scholarship Council and Max Planck Institute
Date of First Compliant Deposit:	29 May 2024
Last Modified:	29 May 2024 14:10
URI:	https://orca.cardiff.ac.uk/id/eprint/169236

Actions (repository staff only)

Edit Item