Hydrogen spillover

[3] Since the phenomenon was not found when using Al2O3 as the catalyst, he claimed that the dissociative chemisorption of H2 molecules on the Pt particles created hydrogen atoms.

[6] In general, the mechanism is thought to proceed via the transfer of neutral hydrogen atoms to the support upon overcoming an activation energy barrier.

[6] This has even been observed at temperatures as low as 180K in metal-organic framework (MOF) catalysts laced with Palladium nanoparticles (PdnP’s).

For PdnP-containing MOFs, in the presence of saturated metal particles, the capacity for hydrogen spillover only relied on the sorbent’s surface area and pore size.

[9] However, problems present in the strength of the hydrogen-support bond; too strong of an interaction would hinder its extraction via reverse spillover and nullify its function as a fuel cell.

[5] With burgeoning interest in alternative energy sources, the prospect of hydrogen’s role as a fuel has become a major driving force for the optimization of storage methods, particularly at ambient temperatures where their application would be more practical for common use.

[11] Another recent study has shown that the synthesis of methanol from both CO and CO2 over Cu/ZrO2 involves the spillover of H atoms formed on Cu to the surface of ZrO2.

Figure 1: Setup of metal catalyst on a support, the support of which can absorb hydrogen atoms. The receptor represents other optional hydrogen deficient compounds, such as graphene in the context of metal catalysis.
Figure 2: Dissociative chemisorption of H 2 on metal catalysts. Hydrogen atoms move from a hydrogen-rich to a hydrogen-poor surface.
Figure 3: Hydrogen storage in carbon materials through spillover techniques. In this case, the receptor is a carbon nanotube. Note that while physical mixtures of a primary hydrogen spillover source and a secondary receptor demonstrate moderate storage capacity, adding a bridge to improve the contact between the support metal and the receptor serves to double or triple hydrogen storage capacity on the receptor.