The solution is based on more general research into the production of nitrogen-containing carbon nanomaterials, i.e., objects ranging in size from 1 to 100 nanometres (billionths of a metre) obtained from carbon. The most well-known nanocarbon material is graphene, which can be used to produce supercapacitor electrodes, devices sought after in electric vehicles and consumer electronics.
The scientists from the Institute of Catalysis SB RAS use two approaches to synthesise nitrogen-containing carbon nanomaterials: nitrogen is incorporated either into the carbon structure of the growing nanomaterial (which ensures its uniform distribution) or into the outer graphene layers. The resulting nitrogen-containing materials are used to create highly dispersed (i.e., consisting of many particles) catalysts that play an important role in the decomposition reaction of formic (methane) acid, which leads to the formation of hydrogen. The scientists from the Institute of Catalysis SB RAS managed to sharply accelerate the reaction in a gas phase environment at a temperature of less than 150 degrees Celsius.
“Thanks to the post-processing method, we can significantly increase the density of nitrogen centres in the outer graphene layers of carbon nanotubes. Effectively attached to these centres is highly dispersed palladium in the form of nanoparticles 1 nm in size and numerous individual atoms. Moreover, post-processing involves the formation of additional surface amine groups, which is essential for the reaction to proceed. Using this method, we were able to increase the reaction rate by five times (up to ~0.5 s-1 at 125 degrees Celsius), which is the highest gas phase reaction rate for this type of catalyst. We also achieved an increase in hydrogen selectivity to 99.4%. Of course, this is not the 100% everyone is aiming for, but in the case of using conventional carbon nanomaterials, selectivity does not exceed 98%,” Olga Podyacheva, doctor of chemical sciences, is quoted as saying by the Institute of Catalysis SB RAS.
The authors are now studying the decomposition of formic acid in a liquid medium at room temperature – in these conditions, hydrogen production could become more economically feasible.
