Synergistic Effects of Ternary PdO–CeO₂–OMS-2 Catalyst Afford High Catalytic Performance and Stability in the Reduction of NO with CO

Abstract

We developed a robust ternary PdO–CeO2–OMS-2 catalyst with excellent catalytic performance in the selective reduction of NO with CO using a strategy based on combining components that synergistically interact leading to an effective abatement of these toxic gases. The catalyst affords 100% selectivity to N2 at the nearly full conversion of NO and CO at 250 °C, high stability in the presence of H2O, and a remarkable SO2 tolerance. To unravel the origin of the excellent catalytic performance, the structural and chemical properties of the PdO–CeO2–OMS-2 nanocomposite were analyzed in the as-prepared and used state of the catalyst, employing a series of pertinent characterization methods and specific catalytic tests. The experimental as well as theoretical results, based on density-functional theory calculations suggest that CO and NO follow different reaction pathways, CO is preferentially adsorbed and oxidized at Pd sites (PdII and Pd0), while NO decomposes on the ceria surface. Lattice oxygen vacancies at the interfacial perimeter of PdO–CeO2 and PdO–OMS-2, and the diffusion of oxygen and oxygen vacancies are proposed to play a critical role in this multicenter reaction system.

Effect of the Configuration of Copper Oxide–Ceria Catalysts in NO Reduction with CO: Superior Performance of a Copper–Ceria Solid Solution

“…–1 ), which is generated by the reaction of CO with O L species. Note that the catalysts with higher O V concentration can enhance N 2 selectivity in the [NO + CO] reaction, in good accordance with previous observations. , In the same way, CO conversions and the O L consumption in A (61.0% and 0.195 mmol g catal. –1 ) are higher than in B (55.5% and 0.171 mmol g catal.…”

“…The catalytic reduction of NO with CO can efficiently eliminate both toxic gases from harmful exhausts, yielding N 2 and CO 2 . , Various precious metal-based catalysts, including Pd, Pt, Rh, Ru, and Ir, as well as Cu-based catalysts are successfully applied for the reduction of NO by CO for gas purification and have recently been reviewed focusing on their physicochemical properties and catalytic performances . Among them, nanocomposites based on CuO–CeO 2 have proven to be very effective and thus are of great interest as alternatives to the more expensive catalysts based on precious metals. − …”

First-Principles Study of NO Reduction by CO on Cu2O(110) and Pd1/Cu2O(110) Surfaces

“…Currently, selective catalytic reduction (SCR) is considered as one of the most effective methods for NO elimination. The commonly used reducing agents are CO, H 2 , NH 3 , and C x H y . − Among them, SCR of NO with CO as reducing agent can simultaneously convert two pollutants (CO and NO) into harmless N 2 and acceptable CO 2 , which has attracted wide attention. − Platinum-based catalysts (Pt, Pd, and Rh) are the active components of three-way catalysts (TWCs) in automotive exhaust emission control systems. − However, the scarcity of resources and high prices limit their practical application prospects.…”

SO2 Poisoning Mechanism of the Multi-active Center Catalyst for Chlorobenzene and NOx Synergistic Degradation at Dry and Humid Environments

“…Moreover, the Pd 3d peak in sulfur poisoned catalysts shifts slightly to higher bonding energy compared with the Fresh catalyst and shifts back after thermal regeneration. In addition, Pd 2+ species have remarkably high catalytic capacity . The Pd 2+ /Pd 0 ratio (2.58) of the Fresh catalyst is also much higher than that (1.85 and 1.67) of the poisoned catalysts, which increases back to 2.43 and 2.27, respectively.…”

“…In addition, Pd 2+ species have remarkably high catalytic capacity. 25 The Pd 2+ /Pd 0 ratio (2.58) of the Fresh catalyst is also much higher than that (1.85 and 1.67) of the poisoned catalysts, which increases back to 2.43 and 2.27, respectively. These changes may be assigned to the formation of sulfate species on the catalyst surface.…”