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Environmental Catalysis

Renowned for its work in the discovery and understanding of gold catalysts, the CCI has a growing skills-base in environmental catalysis that inclues the use of  base metals, alkali metals, metal oxides and other precious metals as well as gold.   Our work is providing new insights into the functions of existing and new catalytic systems for controlling pollutants, either in the atmosphere or in water.

The control of emissions by catalytic oxidation from stationary sources is of ever growing importance. In particular, the removal of VOCs (volatile organic compounds) from waste effluent streams is essential for protection of the environment. Our projects focus on developing new high activity metal oxide catalysts, by investigating novel preparation routes, like nanocasting and supercritical antisolvent precipitation. At the same time, we have a major effort on enhancing activity of supported precious metals by combining metal components with active metal oxide phases, and therefore thrifting the overall metal content. Our group at the CCI is also one of very few working on the abatement of PAHs (polycyclic aromatic hydrocarbons) and has pioneered their control by catalytic oxidation.

The control of carbon monoxide in air is critical for life support, and catalysts capable of oxidising carbon monoxide to carbon dioxide under ambient conditions have numerous applications in areas such as the mining industries, deep sea diving, decompression chambers, breathing apparatus, submarines and space exploration. Although hopcalite (a mixed copper manganese metal oxide) has been used in this application for many years, scope still remains to understand how it operates and produce longer-lasting and more flexible formulations. This is another of our active research areas, in which we are developing gold-based and metal oxide catalysts with enhanced and robust performance.

The three-way car catalyst is an established technology in a mature market, but several fundamental questions relating to its activity remain to be answered.  In collaboration with the University of Oxford, we have been investigating the nature of the positive interaction between the metal nano-particles and the support material (mainly CeO2 and ZrO2).  We have been able to provide a more precise explanation of the electronic changes that occur across the metal-support interface.   This understanding is informing our design of catalysts for diesel-emission control, where the simultaneous removal of NOx, hydrocarbons and soot particulate is required.

Our ability to stabilise the metal-support interactions that lead to enhanced activity could also prove critical to the optimisation of catalysts for new technologies, such as fuel reformers.  In collaboration with the University of Birmingham, we have shown that on-board reforming could be used, in the near-term, as a heat-recovery strategy to improve the fuel economy and lower the CO2 emissions of conventional vehicles.  In the longer term, this technology could be adapted to generate H2 from renewable organic sources, in the long-awaited hydrogen economy.  

The challeges in passenger vehicle pollution abatement also apply to trucks, but on a much larger scale! Trucks emit large amounts of particulate matter and NOx, while operating under oxidising conditions, and so removing all the emitted pollutants efficiently requires scientific and technical advances. We are working with the Swedish truck company Scania to scope methodologies for investigating and diagnosing the performance of the catalytic systems used, with the ultimate aim of identifying routes to improved longevity of such catalysts.

Environmental catalysis

Getting from (a) to (b). The CCI is collaborating with a number of motor manufacturers, developing the next generation of advanced vehicle exhaust control technologies. These manufacturers include Jaguar Land Rover, General Motors and Scania.