Hydrogen adsorbs rapidly into cold palladium. At about 260°F hydrogen begins to desorb slowly. When gas is absorbing, the nanoparticle heats up and when it is desorbing it cools down. No arguments there.
At somewhere around 300°F there is an emergent see-saw dynamic where the cooling (caused by desorption) reverses the flow and permits re-adsorption -- and the heat created by that then encourages further desorption, ad infinitum. This back and forth process can be viewed as a rapid pumping effect. Nanoparticles speedup the oscillation rate. A good paper on adsorption and desorption of hydrogen into palladium is: “Adsorption and Desorption of Hydrogen by Gas-Phase Palladium Clusters Revealed by In Situ Thermal Desorption Spectroscopy.” Masato Takenouchi, et al. A second, reinforcing activity for that See-saw activity is happening when hydrogen is present along with red photons. At the same reactor parameters (as the palladium adsorption/desorption cycle) we can have an optical reflectivity cycle. A helpful paper is: “Plasmonic Surface Lattice Resonances: A Review of Properties and Applications” V. G. Kravets et al. Red photons of one wavelength have an unusual (anomalous) effect on palladium as they form plasmons –the metal strongly absorbs 95% of photons at 650 nm but light of higher and lower wavelength is mostly reflected. This can create a thermal cycling which is also a pumping action but only when hydrogen is adsorbed. That is because hydrogen quenches the optical anomaly. Thus there is positive feedback between the two systems. There is an opto-thermal resonance as well as positive feedback. The major intermediate result seems to be a rapid pumping action moving molecules of hydrogen in-and-out of the palladium nanoparticles - assisted by resonant photon irradiation. >From there on - it is not clear what exactly this pumping action accomplishes >- but one intriguing possibility is condensation - IOW this is how hydrogen >becomes densified. Following densification, other things can happen, but it >would be a big step forward to optimize the condensation step. Jones
