Fabrication of Spinel-Type PdxCo3–xO4 Binary Active Sites on 3D Ordered Meso-macroporous Ce-Zr-O2 with Enhanced Activity for Catalytic Soot Oxidation

In diesel soot oxidation studies, both well-defined model soot and a reliable means to simulate realistic contact conditions with catalysts are crucial. This study is the first attempt in the field to establish a lab-scale continuous flame soot deposition method in simulating the “contact condition” of soot and a structured diesel particulate filter (DPF) catalyst. The properties of this flame soot were examined by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM) for structure analysis, Brunauer-Emmett-Teller (BET) for surface area analysis, and thermogravimetric analysis (TGA) for reactivity and kinetics analysis. For validation purposes, catalytic oxidation of Tiki® soot using the simulated contact condition was conducted to compare with the diesel particulates collected from a real diesel engine exhaust system. It was found that the flame soot is more uniform and controllable than similar samples of collected diesel particulates. The change in T50 due to the presence of the catalyst is very similar in both cases, implying that the flame deposit method is able to produce comparably realistic contact conditions to that resulting from the real exhaust system. Comparing against the expensive engine testing, this novel method allows researchers to quickly set up a procedure in the laboratory scale to reveal the catalytic soot oxidation properties in a comparable loose contact condition.

Download Full-text

Single‐Atomic Ruthenium Active Sites on Ti3C2 MXene with Oxygen‐Terminated Surface Synchronize Enhanced Activity and Selectivity for Electrocatalytic Nitrogen Reduction to Ammonia

ChemSusChem ◽

10.1002/cssc.202102352 ◽

2021 ◽

Author(s):

Gang Chen ◽

Mingmei Ding ◽

Kai Zhang ◽

Yueting Wang ◽

Jun Ma ◽

...

Keyword(s):

Active Sites ◽

Nitrogen Reduction ◽

Enhanced Activity

Download Full-text

Impact of Diesel/CNG Dual-Fuel Combustion on Exhaust Soot Characteristics

ASME 2016 Internal Combustion Engine Fall Technical Conference ◽

10.1115/icef2016-9469 ◽

2016 ◽

Author(s):

Karthik Nithyanandan ◽

Yilu Lin ◽

Robert Donahue ◽

Xiangyu Meng ◽

Yuanxu Li ◽

...

Keyword(s):

Active Sites ◽

Particle Diameter ◽

Soot Oxidation ◽

Fuel Combustion ◽

Operating Conditions ◽

Intake Manifold ◽

Dual Fuel ◽

Exhaust Pipe ◽

Oxidation Reactivity ◽

Dual Fuel Combustion

This paper presents the chemical composition, oxidation reactivity and nanostructural characteristics of particulate matter (PM) produced by a diesel engine operating with diesel/compressed natural gas (CNG) dual-fuel combustion. Raw, undiluted soot samples from pure diesel, 40% CNG, and 70% CNG (energy-based substitution rate) combustion were collected from the exhaust pipe. Engine operating conditions were held at 1200 RPM and 20 mg/cycle baseline load. For dual-fuel operation, split diesel injection (two injections) was used as the pilot, and CNG was injected into the intake manifold. First, soot oxidation reactivity was characterized using thermogravimetric analysis (TGA). Carbon, hydrogen, and nitrogen weight fractions were obtained using elemental analysis to measure soot aging. Transmission electron microscopy (TEM) was then used to determine the diameter of the spherules, and the morphology of soot agglomerates. It was found that soot reactivity increased with increasing CNG content. TEM images revealed a higher variation in particle diameter with increasing CNG substitution. High resolution TEM (HRTEM) images showed that CNG70 soot displayed features of immature soot particles. The enhanced reactivity could also be due to more active sites available in CNG soot, as well as the CNG soot being immature. Under this test condition and engine configuration, it can be concluded that the use of CNG affects the morphology and nanostructure of PM, and hence the oxidation reactivity of the soot.

Download Full-text