Low‐Temperature CO Oxidation over a Ternary Oxide Catalyst with High Resistance to Hydrocarbon Inhibition

Abstract

Platinum group metal (PGM) catalysts are the current standard for control of pollutants in automotive exhaust streams. Aside from their high cost, PGM catalysts struggle with CO oxidation at low temperatures (<200 °C) due to inhibition by hydrocarbons in exhaust streams. Here we present a ternary mixed oxide catalyst composed of copper oxide, cobalt oxide, and ceria (dubbed CCC) that outperforms synthesized and commercial PGM catalysts for CO oxidation in simulated exhaust streams while showing no signs of inhibition by propene. Diffuse reflectance IR (DRIFTS) and light-off data both indicate low interaction between propene and the CO oxidation active site on this catalyst, and a separation of adsorption sites is proposed as the cause of this inhibition resistance. This catalyst shows great potential as a low-cost component for low temperature exhaust streams that are expected to be a characteristic of future automotive systems.

Highly Efficient Removal of CO in Effluent Streams from Real‐Life Propane Oxidation Process over CuO−CeO2−Based Catalysts

“…CO 2 , inferring an excellent tolerance to them. The high for which CO oxidation is believed to occur preferentially at interface sites of copper‐ceria, while the oxidation of hydrocarbons primarily takes place on the surface of CuO or Co 3 O 4 . This separation of active sites for CO and hydrocarbon oxidation as well as a low oxidation activity of hydrocarbons at low temperature over the CuO−CeO 2 −Co 3 O 4 catalyst could reduce or eliminate inhibitory competition.…”

“…CuO−CeO 2 −Co 3 O 4 mixed oxide was prepared by co‐precipitation method as described elsewhere . Briefly, a proper mixture of Cu(NO 3 ) 2 ⋅3H 2 O, Ce(NO 3 ) 3 ⋅6H 2 O and CoCl 2 ⋅6H 2 O with Cu : Ce : Co molar ratio of 1 : 5 : 5 was dissolved in deionized water at room temperature.…”

Demonstrating the Potential of Chemiluminescence as a Tool to Characterize Heterogeneous Catalysis Using CO Oxidation on Copper‐Based Catalysts as an Example

“… CO oxidation over copper‐based catalysts is industrially and environmentally important. For example, copper‐based catalysts have potential as a low‐cost alternative to PGM catalysts in the automotive industry Various reaction mechanisms have been reported for CO oxidation over copper‐based catalysts. Although CL emission under CO oxidation over flower‐like copper oxide has been reported, its CL emitting mechanism was not studied …”

“…CO oxidation over copper‐based catalysts is industrially and environmentally important. For example, copper‐based catalysts have potential as a low‐cost alternative to PGM catalysts in the automotive industry …”

Copper–Cobalt–Cerium Ternary Oxide as an Additive to a Conventional Platinum‐Group‐Metal Catalyst for Automotive Exhaust Catalysis

“…Additionally, the high cost of the precious‐metal components in traditional PGM catalysts spurs demand for low‐costing alternatives that can function at lower temperatures. Previously, we reported a ternary oxide catalyst composed of CuO, Co 3 O 4 , and CeO 2 (dubbed CCC) that showed high activity for CO oxidation in simulated lean exhaust streams relevant to lean‐burning diesel engine emissions . Although this catalyst was able to overcome hydrocarbon inhibition in the CO oxidation reaction at low temperatures, a common inhibitor of PGM‐based catalysts, its propene oxidation activity was low relative to that of the PGM standard.…”