Oxidation of Trace Ethylene at 0 °C over Platinum Nanoparticles Supported on Silica

Abstract

Oxidation of trace ethylene (50 ppm) at 0 °C was systematically studied using Pt nanoparticles supported on mesoporous silica (SBA-15) in a fixed-bed flow reactor. The SBA-15 supported Pt catalyst (1.8 wt % Pt loading) exhibited an ethylene conversion higher than 99% at the initial stage, which gradually began to decrease at 90 min and reached 33% within 240 min. The CO2 yield was lower than the corresponding ethylene conversion before the steady state was reached. This was due to the formation of intermediates that were stabilized on the catalyst surface. These intermediates could be recovered in the form of CO2 by heating the spent catalyst in a mixed N2 and He (1:19, v/v) flow at 150 °C. The addition of water vapor to the catalyst bed decreased the original activity drastically because physically adsorbed water molecules partly blocked the active Pt sites. Control experiments using nonordered silica supports (Aerosil 380 and 200) showed similar catalytic behavior as that observed with SBA-15. The formation of highly dispersed Pt nanoparticles on the silica surfaces is thus the key to the development of effective Pt catalysts for low-temperature oxidation of ethylene.

Water-Resistant Pt Sites in Hydrophobic Mesopores Effective for Low-Temperature Ethylene Oxidation

“…17,18 TEM measurement of Pt/A380(800) in this study shows that Pt nanoparticles in size of 5.5 nm are highly dispersed on A380(800) surface (FiguresS1(C) and (D)). Structural parameters and catalytic activity for silica-supported Pt catalysts.…”

“…The difference between conversion and yield will disappear when prolonging the reaction time, which means the reaction reaches actual steady-state. 17 However, extremely low ethylene concentration requires a high SV and a long reaction time to assess the steady-state activity.…”

Hierarchical Porous Wood Cellulose Scaffold with Atomically Dispersed Pt Catalysts for Low-Temperature Ethylene Decomposition

“…The results revealed that the ethylene conversion capacity could be recovered by removing the water molecules accumulated on the Pt surfaces. According to the previous study, the ethylene decomposition over the catalyst occurs via the HCHO intermediate state. The reaction starts with the absorption of ethylene molecules on the Pt species.…”

Yttrium stabilization and Pt addition to Pd/ZrO2 catalyst for the oxidation of methane in the presence of ethylene and water

“…9,10 However, the deactivation due to sintering at high reaction temperature (400-600 C) and wet (H 2 O) feeds remains a challenge. 9,10 Attempts have been made to resolve catalyst deactivation by adding Pt to Pd-based monometallic catalysts. [11][12][13][14] Nevertheless, the inuence of Pt on the improvement of bimetallic Pd-Pt catalysts is inconclusive.…”