UC Doctoral Engineering Student Receives Prestigious Gerondelis Foundation Grant

Dimitrios Pappas

, University of Cincinnati College of Engineering and Applied Science (CEAS) doctoral chemical engineering student, has been selected to receive a $4,000 grant from the Gerondelis Foundation. With this grant, Pappas plans to continue his novel environmental research with Professor Panagiotis Smirniotis, CEAS chair of chemical engineering, and Thirupathi Boningari and post-doctoral fellow.

The Gerondelis Foundation Inc. is a private foundation with offices in Lynn, Mass. The organization makes grants for use by students from Greece who hold a Greek undergraduate degree and who have been accepted into a graduate degree or certificate granting program at an American university or other institution of higher learning. Recommendations are received from the educational organizations describing the qualifications of the applicant and the amount of the financial aid needed. The Foundation then makes grants based upon these recommendations directly to the educational organizations along with a letter or letters listing the student or students for whom financial aid is being granted.

Pappas’ research is focused on the reduction of highly reactive gasses known as nitrogen oxides (NOx) and more specifically, their Selective Catalytic Reduction (SCR) into nitrogen. NOx emissions originate in cars, trucks and buses, power plants, and off-road equipment and have been linked to a number of adverse effects involving the respiratory system.

SCR is a process in which nitrogen oxides are reduced by using a catalyst and a reducing agent (such as ammonia, urea and light hydrocarbons) in order to produce nitrogen and water. Although SCR is a well-established process utilized by industrial boilers and by many Diesel engine trucks, ships and gas turbines, it has certain drawbacks that are preventing its further application and full commercialization—Pappas and his fellow researchers are working to change this.

Pappas and his colleagues have discovered novel catalytic formulations that will be active for the process in a wide temperature range, especially in the low temperature region (100-250°C), while also resisting sulfur poisoning and remaining hydrothermally (being stable at high temperature and relative high water vapor content) stable. Pappas collaborates with Professor Panagiotis Smirniotis, CEAS chair of chemical engineering, and Thirupathi Boningari, post-doctoral fellow.

“By creating highly active and tolerant catalytic formulations for the low temperature range, SCR will have great potential to be fully commercialized and used by the automotive industry, reducing the nitrogen oxide emission from mobile sources.

The employment of catalytic converters for the selective catalytic reduction on vehicles will lead to a significant reduction of nitrogen oxide pollution, thereby minimizing environmental problems related to these pollutants leading to a much cleaner and sustainable environment.

From an economical aspect, the development of such catalysts eliminate the retrofit costs and operating problems associated with the other catalysts working at medium to high temperatures,” explains Pappas.

The research Pappas performs to develop catalytic formulations consists of three steps, all of which use state-of-the-art techniques. These steps include:

1. The investigation of metal oxides (which are the active component of the catalysts) supported on materials such as TiO2 and zeolites which both induce certain properties to the catalytic formulation.
2. The crucial step is to test the created catalysts for the reduction of nitrogen oxides. The evaluation of the catalytic activity is conducted using numerous conditions strictly relevant to real-world applications. The catalysts are also tested for their sulfur resistance and their hydrothermal stability. Studies to investigate the mechanism and the kinetics of certain catalytic formulations are also administered.
3. The final step is the characterization of the materials to provide useful insights on their performance. Materials are characterized by studying their surface area, pore size distribution, Lewis and Brönsted acid sites (determining the acidity, the number & type of acidic sites), ammonia adsorption, reducibility, crystallinity and oxidation states of the developed catalysts.

Over the past decade, NOx emissions have been the subject of intense research due to challenges arising from current technology for post-combustion removal of NOx and emission (tail pipe emission) regulations. Future standards will require passenger and light-duty diesel vehicles to have nearly 90 percent NOx conversion over the Federal Test Procedure (FTP). This requirement is especially demanding for low temperature exhaust applications like the ones Pappas investigates. SCR via ammonia is shaping up to be one of the most promising NOx control strategies for automobile engines, particularly diesel engines, to meet the increasingly strict standards for NOx emissions.

In response to these demands, the Panagiotis G. Smirniotis Group, with Pappas as a pivotal member, has been conducting research on SCR at UC since 1998. They are among the world’s leading research groups with over 25 published papers in the field and two US patents pending jointly with two industrial sponsors.

The group recently initiated several important and high-potential research projects relevant to chemical and materials science as well as advanced clean environment technologies. Under the sponsorship of national funding agencies such as the National Science Foundation, the Department of Energy, and the Ohio Coal Development Office, the Smirniotis Group has made numerous advancements through pioneering contributions. Some of their contributions include:

• The development of catalytic formulation contributing to the environment protection from nitrogen oxides pollution,
• NOx reduction for coal-fired gas-fired power plants and diesel engines, and
• The development of nanomaterials using flame spray pyrolysis (a novel material synthesis technique) for the catalytic reduction of NOx.

Pappas reflects, “This research has given UC and CEAS great visibility at both national and international levels. I’m very grateful to work and have worked alongside wonderful, passionate and highly intellectual people such as Dr. Panagiotis Smirniotis, Dr. Thirupathy Boningari, and Dr. Athanasios Konstandopoulos of the Centre for Research & Technology in Greece.

I plan to pursue this research beyond my academic career as I believe it will be fruitful and contribute to advancing our way of living.”