Preparation of 3DOM ZrTiO4 Support, WxCeMnOδ/3DOM ZrTiO4 Catalysts, and Their Catalytic Performance for the Simultaneous Removal of Soot and NOx

Abstract

As an efficient and durable engine, a diesel engine has a broad application. However, soot particles (PM) and nitrogen oxides (NOx) coming from diesel engines are the main causes of air pollution, so it is necessary to design and prepare an effective catalyst for the simultaneous elimination of PM and NOx. In this work, a novel 3DOM ZrTiO4 support and a series of WxCeMnOδ/3DOM ZrTiO4 catalysts (where x indicates the wt% of W) were designed and fabricated by the colloidal crystal template technique. Among the as-prepared catalysts, the W1CeMnOδ/3DOM ZrTiO4 catalyst exhibits the highest NO conversion rate (52%) at the temperature of maximum CO2 concentration (474°C) and achieves 90% NO conversion in the temperature range of 250–396°C. The excellent catalytic performance is associated with the macroporous structure, abundant oxygen vacancies, sufficient acid sites, and the synergistic effect among the active components. The possible reaction mechanisms of WxCeMnOδ/3DOM ZrTiO4 catalysts were also discussed based on the characterization results.

Research Progress on Preparation of Metal Oxide Catalysts with Porous Structure and Their Catalytic Purification of Diesel Engine Exhausts Gases

“…In addition to the metal oxides with porous structures mentioned above, catalysts with supported 3DOM structures have been used for simultaneous PM and NO x elimination. In our group, Wang et al 440 synthesized a series of W x CeMnO δ / 3DOM ZrTiO 4 catalysts using 3DOM ZrTiO 4 as a carrier and investigated the mechanism of simultaneous PM and NO x elimination by the catalysts, as shown in Figure 27G. The results indicated that, during the PM elimination process, 3DOM W 1 CeMnO δ /3DOM ZrTiO 4 catalyst generates more active oxygen species.…”

“…Copyright 2021 The Authors. Published by American Chemical Society), (G) W x CeMnO δ /3DOM ZrTiO 4 (Reprinted with permission under Creative Commons CC-BY 4.0 license from ref . Copyright 2022 The Authors), (H) Mn x Co 1– x O δ /3DOMm Ti 0.7 Si 0.2 W 0.1 O y (Reprinted with permission from ref .…”

“…On the basis of the above results, the researchers proposed a reaction mechanism for the simultaneous elimination of PM and x by the La 0.5 K 0.5 0.97 Pd 0.03 O 3 catalyst, as shown in Figure 27E where the reactive oxygen atoms generated from oxygen vacancies and NO In addition to the metal oxides with porous structures mentioned above, catalysts with supported 3DOM structures have been used for simultaneous PM and NO x elimination. In our group, Wang et al 440 synthesized a series of W x CeMnO δ / 3DOM ZrTiO 4 catalysts using 3DOM ZrTiO 4 as a carrier and investigated the mechanism of simultaneous PM and NO x elimination by the catalysts, as shown in Figure 27G. The results indicated that, during the PM elimination process, 3DOM W 1 CeMnO δ /3DOM ZrTiO 4 catalyst generates more active oxygen species.…”

The Effect of Potassium Inclusion in a Silver Catalyst for N2O-Mediated Oxidation of Soot in Oxidising Exhaust Gases

“…Although an SCR catalyst can be coated onto a DPF to form an integrated unit (referred to as SCRF [7], SCRoF [8] or SPDF [9]), the filter still requires active regeneration by the injection of fuel into an upstream DOC. Therefore, the challenge remains to design a catalysed filter in which the chemistry of NOx-reduction is coupled with that of continuous soot oxidation [10] (e.g., using perovskites [11] or 3DOM mixed-metal oxides [12]), so avoiding the requirement for intermittent regeneration of the filter. We have previously shown [13,14] that catalysts based on Ag/CZA (silver supported on ceria-zirconia-alumina), in which the functions of incomplete NOx reduction and soot oxidation are combined, have the potential to control soot particulate and NOx emissions at the low temperatures typical of the exhaust gas emitted by the engine of a diesel passenger car.…”