Platinum-Graphene Heterogeneous Catalysts for Hydrogen Mitigation Applications

With the use of hydrogen as an energy source, mitigation of its leakage in the environment is critical. Therefore, it is required that passive autocatalytic hydrogen–oxygen (H–O) combination systems are developed to combine this hydrogen with oxygen from the air. In the present study, reduced graphene oxide (rGO) sheets loaded with platinum nanoparticles have been developed and studied for their performance as catalysts for hydrogen dissociation as well as its combination with oxygen. The formation of platinum particulates on rGO substrate was confirmed by XRD and SEM. Crystallite sizes of platinum nanoparticles were in the range of 7.8–8.3 nm. However, the platinum particles had spherical morphology with an average particle size of 90 nm when seen through SEM. The particle size distribution was almost similar irrespective of platinum loading. At lower platinum contents, the number density of platinum particles was lower but as the number density of the particles increased with an increase in loading they tended to agglomerate. These platinum-loaded rGO samples were employed as catalysts for hydrogen dissociation kinetic studies using hydrogen deuteride formation as an indicating tool. It was found that the dissociation rate per unit mass improved with an increase in platinum loading up to 11 wt% (Pt11@rGO) and then decreased. When used for (H–O) combination reaction, Pt11@rGO demonstrated the highest combination rates per unit mass of catalyst. Consequently, Pt11@rGO catalyst gave the best performance with regard to the economic use of precious metals for catalytic application. This catalyst may be a potential candidate for traditional as well as futuristic hydrogen mitigation applications.