Grantee Research Project Results
2021 Progress Report: PanCeria: Catalytic NO and CO Emission Control Unit for Small Off-road Engines
EPA Grant Number: SV839488Title: PanCeria: Catalytic NO and CO Emission Control Unit for Small Off-road Engines
Investigators: Crocker, David A. , Tam, Kawai , Gracia, Kyah , Ramirez, Ariel , De Oca, Sarah Montes , Kahn, Shamia
Institution: University of California - Riverside
EPA Project Officer: Page, Angela
Phase: II
Project Period: May 1, 2019 through April 11, 2020 (Extended to October 31, 2023)
Project Period Covered by this Report: May 1, 2021 through April 30,2022
Project Amount: $74,926
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2019) Recipients Lists
Research Category: P3 Awards , P3 Challenge Area - Air Quality
Objective:
Combustion of fossil fuels releases oxides of nitrogen (NOx) into the atmosphere contributing to smog formation and declining air quality. Smog is a serious health hazard as it promotes respiratory complications and diseases, heart problems, and weakened immune systems to name just a few1. Over the years there have been many laws passed to regulate automotive, manufacturing, and energy industries. However, the regulation of small off-road engines (SOREs) has been overlooked and are one of the leading causes to the decline of air quality. According to the United States Environmental Protection Agency (EPA), Gasoline-powered Lawn and Garden Equipment (GLGE) are one of the worst air polluters in California4. It’s predicted that these small off-road engines will surpass vehicle emissions in a few years. To reduce these emissions, PanCeria’s main objective is to develop a catalytic converter capable of reducing carbon monoxide (CO) particulate matter (PM), and nitrogen oxide (NOx) from these SOREs used in lawn and garden maintenance. The efforts of the project contribute to human health, human welfare, and the prosperity and improvement of the planet.
The current catalyst prototype functions in two different phases. The first phase is the mesh filter. The mesh filter will collect large particulate matter, such as dust or soot, preventing the PM from escaping off the exhaust into the atmosphere. This filter also helps prevent the channels of the monolith housing from becoming clogged and reducing useable catalyst surface area. The second phase is the reduction of NO via CO oxidation over the copper/cerium catalyst (Cu/CeO2)3.
Progress Summary:
The previous team, from 2018-2019 conducted bench-scale testing of the catalyst. In this experiment, they had demonstrated a proof of concept for the reduction of NO via CO oxidation2. The previous team chose to use the wet impregnation technique to synthesize the catalyst, and tried several different mixing methods to synthesize a 5% weight loaded catalyst. At CE-CERT, the team had performed temperature tests to confirm the reduction of NO using a chemiluminescent NOx analyzer. Using a vortex instrument to mix, the team found using a vortex to be the best mixing method for the best selectivity for the catalyst. Further analysis was needed to determine the activity of the catalyst and the percent weight of Cu that was loaded onto the catalyst. To confirm the weight loaded amount, and other characteristics of the catalyst SEM imaging was performed by the 2021-2022 team.
The most recent team spent a large chunk of time refining the blueprint of the catalyst left by former teams work. Due to the pandemic research and production of the catalyst for testing had been halted. Subsequently the teams had graduated during the pandemic creating a gap in workflow on the PanCeria research. The recent team spent the year trying to recreate a catalyst that would have both the 5% target weight loading, as well as favorable selectivity and activity. Due to technical challenges in replicating earlier teams research, the current team started over synthesizing a viable catalyst to use for experimentation and product development. The goal of this team was to create the new catalyst, and further characterize it to confirm the 5%wt loading, as well as have the catalyst display good catalytic properties once on the monolith housing, and in the emissions system. Confirmation of the 5%wt Cu on the cerium was confirmed for the new catalyst using Scanning Electron Microscope (SEM) imaging.
The team tried all the mixing methods tried by previous teams that had synthesized catalytic material but had many failures attaining the 5% weight loaded catalyst. The previous report stated that vortex mixing had the best reduction of NO; however, in the SEM characterization performed by the current team, found that vortex mixing actually yielded the lowest %wt catalyst. Stirring during synthesis was discovered to yield the highest dispersion of Cu nanoparticles. Some of the issues encountered in getting 5%wt Cu was due to evaporation during processing--when attempting to dry the catalyst material many experimental trials were needed to optimize settling of the Cu nanoparticles onto the cerium sites when doing the He/H gas blend reduction step in catalyst synthesis. Eventually the current team was able to make 5 batches of 10g catalyst material confirmed through SEM/EDS mapping and imaging near the 5% target weight. The team then dipped the catalyst onto the cordierite monolith housing. The current PanCeria team purchased a new gas analyzer for verification of the catalyst performance, however manufacturer delivery delays of 9 months prevented final testing of the catalyst during this iteration and has been left to next years team. The pandemic had affected the supply chain for many instrument companies, which was the first delay in receiving the gas analyzer. The second delay was due to the instrument not passing QA/QC checks due to a board failure that took months to resolve. The third delay was with shipping, and by the time the box had arrived, the current team was graduating. This halted the observation of known %wt and its relationship with the catalytic activity and kinetics that were hoped to be observed. The Cocker lab now has the box in its possession, calibrated and verified for the 2022-2023 team, and the PanCeria team has complete priority to use the gas analyzer to help accelerate the timeline for property data to arrive. The physical system is ready as well, and just needs to load the five different catalysts to observe the reduction and activity of the catalysts. SOREs ready to be tested are a gas generator, lawn mower, and leaf blower (all prepped for testing by the current team). Based upon the work from the 2021-2022 team, and known available resources to the next team, the other goal is to produce more 5%wt catalysts to test in the system and determine the true catalytic properties and kinetics of a 5%wt Cu loaded cerium oxide catalyst. Below are some SEM images and % distribution the recent team performed to confirm the catalytic material had 5%wt Cu within a +/- .2 tolerance. From the 17 created catalyst material, only 5 so far have displayed to reach 5% weight within a +/- .2 tolerance. The reason for so many samples to fail to hit near the 5% mark is due to the use of the wet impregnation method. The method is very broad and general use for doping materials onto sites and may not represent the most optimized method.
Fig. 1 is the map spectrum graph acquired by SEM-EDS imaging of one of the stirred samples
Fig. 2 is an SEM image with EDS layering of the same sample from figure 1
Future Activities:
With promising samples ready to go, and the system for testing already built, the experimental data for the research should populate quickly. There is now a digital folder containing all the SOPs, methods, corrections, and suggestions from the 2021-2022 team ready to be passed on to the next team. The plan for the next team is to immediately begin testing the 5 fully synthesized catalysts, and further correct and improve the techniques and methods used to improve the kinetics, activity, and selectivity of the catalyst based on the preliminary data from those 5 samples. The SOREs tested will be a gas generator, lawn mower, and leaf blower. The next team leader was a member from the recent team, and this will help pass along knowledge as the research on PanCeria grows and develops for presentation in 2023. The goal and objective remain the same, and PanCeria still shows promise to create an economic catalyst to help reduce the emissions from SOREs.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 1 publications | 1 publications in selected types | All 1 journal articles |
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Zhang SM, Huang WP, Qiu XH, Li BQ, Zheng XC, Wu SH. Comparative study on catalytic properties for low-temperature CO oxidation of Cu/CeO2 and CuO/CeO2 prepared via solvated metal atom impregnation and conventional impregnation. Catalysis letters 2002;80(1):41-6. |
SV839488 (2021) |
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Supplemental Keywords:
Catalysts, Nanomaterial, Emissions, Emissions reduction, CO oxidationProgress and Final Reports:
Original AbstractP3 Phase I:
PanCeria NOx Reducing Device: Selective Catalytic Reduction System for Emission Control of Small Off-Road Engines | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.