Driven to reduce engine emissions

Research and innovation
Faculty of Engineering

By Stephen Dale

Writer, Freelance

Yasmine Hajar
Doctoral student Yasmine Hajar explores electrochemical processes that may lead to cleaner cars.

The science behind Yasmine Hajar’s doctoral research in chemical engineering may be complex but its goal is simple: to drastically improve the efficiency of pollution control devices to reduce greenhouse gas emissions from cars.

Hajar is confident that if her project yields the expected results, more efficient catalytic converters—the devices that enable car engines to burn fuel more completely—can be incorporated into automobiles everywhere.

Clearly, others see the potential in the University of Ottawa student’s research as well. Last year, Hajar was awarded the prestigious NSERC Vanier Canada Graduate Scholarship—the first time an engineering student has been given that honour in more than five years. Among the dignitaries on hand for the announcement were federal Health Minister Jane Philpott and Science Minister Kirsty Duncan.

The journey to Hajar’s potentially groundbreaking research began after a high school fascination with chemistry led her to undergraduate work in chemical engineering at the University of Balamand in her native Lebanon.

Hajar worked on petroleum at Balamand. After moving to Canada for her masters’ studies, she says, “I fell in love with the whole environmental aspect of being a chemical engineer and the challenges that come with it.” At Queen’s University, she examined how sulphur— a waste by-product of petroleum production—could be transformed into industrial gypsum and produce electric energy more efficiently than coal.

Now under the supervision of engineering professor Elena Baranova (who has run a lab on the environmental applications of electrochemical engineering and catalysis for the past nine years), Hajar works on a process called electrochemical promotion of catalysis. Recent research in this field shows that the application of electric stimuli modifies the characteristics of a catalyst’s surface, which then improves the efficiency of the chemical reaction produced in catalytic converters.

Hajar’s project extends this work to nanoscale catalyst materials with a low noble, or expensive, metal content. Other than electrically promoting nanoparticles of classic noble metals such as platinum, palladium or ruthenium, Hajar focuses on changing the characteristics of cheap nickel and silver to behave like noble metals, therefore increasing the technology’s economic viability.

The main impact of moving to nanoparticles of metal is allowing more efficient combustion, even when an engine has not warmed up, so it will emit fewer volatile organic compounds, carbon monoxide, methane and other chemicals.

Baranova says her lab’s work on catalysis is innovative and combines a multidisciplinary approach to produce multifunctional catalytic materials and devices to clean vehicle exhaust from gasoline, diesel and natural gas engines.

Hajar says the prospect of ultimately being able to build a prototype catalytic reactor underscores the gratifying, hands-on nature of chemical engineering. “Creating reactors and nanoscale catalysts with my own hands is the type of art I make,” she explains, “and knowing it can be used for the good of the environment is very rewarding.”