Researchers at the Indian Institute of Technology (IIT), in collaboration with scientists from IIT Kanpur and the University of Campinas, Brazil, have developed a graphene-based nanocomposite material that can selectively convert environmental carbon monoxide into less toxic carbon dioxide.
The new composite material is made of graphene and an alloy of platinum and palladium in the form of nanoparticles. In the project, graphene was used as a substrate and then decorated with alloy nanoparticles made of platinum and palladium. The novel catalytic structure was then used for selective oxidation of CO into CO2. The use of a metal particle of certain orientation which absorbs or interacts with CO at lower energy reportedly helped the conversion.
Once integrated, it is the size and shape of the nanoparticles that control the catalytic efficiency of the hybrid material. The efficiency of any catalyst depends on the availability of active sites and the surface area of nanoparticles. Therefore, engineering the morphology of alloy nanoparticles and their integration with graphene is critical to achieve catalytic performance, said Dr. Chandra Sekhar Tiwary, a member of the research team at IIT Gandhinagar.
While platinum and palladium, on their own, are active catalysts, alloying them with graphene does wonders. The hybrid has shown high adsorption and reaction due to synergism among the three, Prof. Sudhanshu Sharma, also from IIT Gandhinagar, said.
The catalytic behavior of the nanocomposite was examined using different morphologies for the oxidation of CO. The conversion rate varied along with the flow rate of CO as well as temperature, showing full conversion at temperatures ranging from 75° to 125°. These are initial results which are exciting. We are trying to build 3D porous architecture using such a hybrid for practical applications and at room temperature, Dr. Tiwary said.
The team stated that the new material could find potential uses in chemical industries as well as environmental cleaning. There is, however, a note of caution. While the concept used is novel and important as CO is a major environmental problem, it may take a while for this science to be converted into technology because the experimental set-up appears complex and may not be commercially viable, said Dr. Ramavatar Meena, a scientist at the Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, who is not connected with the present study.