Lowering the Operating Temperature of Gold Acetylene Hydrochlorination Catalysts Using Oxidized Carbon Supports

Abstract

The commercialization of gold for acetylene hydrochlorination represents a major scientific landmark. The development of second-generation gold catalysts continues with a focus on derivatives and drop-in replacements with higher activity and stability. Here, we show the influence that the support surface oxygen has on the activity of carbon supported gold catalysts. Variation in the surface oxygen content of carbon is achieved through careful modification of the Hummers chemical oxidation method prior to the deposition of gold. All oxidized carbon-based catalysts resulted in a marked increase in activity at 200 °C when compared to the standard nontreated carbon, with an optimum oxygen content of ca. 18 at % being observed. Increasing oxygen and relative concentration of C–O functionality yields catalysts with light-off temperatures 30–50 °C below the standard catalyst. This understanding opens a promising avenue to produce high activity acetylene hydrochlorination catalysts that can operate at lower temperatures.

Reaction-Driven Dynamic and Reversible Transformations of Au Single Atoms and Au–Zr Alloys on Zirconia for Efficient Acetylene Hydrochlorination

“…Such insights are paramount for the development of high-performance catalysts that align with the sustainability objectives of contemporary society. − One notable application lies in the production of vinyl chloride monomer (VCM) through acetylene hydrochlorination, a process historically reliant on mercury-based catalysts fraught with substantial health and environmental risks. − The transition to a sustainable production process necessitates economically viable alternative catalysts. Carbon-supported gold-based catalysts have emerged as prominent contenders, exhibiting significant activity thanks to recent strides in controlling their atomic architecture. − Nonetheless, gold-based catalysts often face deactivation from the active metal site reduction, agglomeration, or fouling. To enhance catalyst stability, various strategies have been devised, including the utilization of organic ligands with soft donor atoms, , ionic liquids, ,, additional metals or promoters, , and functionalized supports. , …”

“…Carbon-supported gold-based catalysts have emerged as prominent contenders, exhibiting significant activity thanks to recent strides in controlling their atomic architecture. − Nonetheless, gold-based catalysts often face deactivation from the active metal site reduction, agglomeration, or fouling. To enhance catalyst stability, various strategies have been devised, including the utilization of organic ligands with soft donor atoms, , ionic liquids, ,, additional metals or promoters, , and functionalized supports. , …”

“…26−33 Nonetheless, goldbased catalysts often face deactivation from the active metal site reduction, agglomeration, or fouling. To enhance catalyst stability, various strategies have been devised, including the utilization of organic ligands with soft donor atoms, 19,32 ionic liquids, 22,25,28 additional metals or promoters, 28,33 and functionalized supports. 12,30 Among these studies, recent research has focused extensively on the relationship between the gold mobility and catalytic activity, particularly on oxide supports.…”

Halloysite nanotube-supported bismuth catalysts for acetylene hydrochlorination

“…4,5 Therefore, exploring new non-mercury catalysts with high efficiency and the potential to be industrialized is an urgent task in acetylene hydrochlorination for PVC production. 6,7…”

“…4,5 Therefore, exploring new nonmercury catalysts with high efficiency and the potential to be industrialized is an urgent task in acetylene hydrochlorination for PVC production. 6,7 In recent years, extensive studies on noble metal (including Au, Pd, Pt, Ru, Rh, Ir, etc.) catalysts have been performed and gold-based catalysts are the most promising candidates.…”