Insights of hydrogen adsorption and dissociation on Ni doped Mg-4 clusters: A DFT study

Hydrogen adsorption and dissociation on Mg-4 and NiMg3 clusters are studied using DFT method. Physisorption of hydrogen molecule on Mg-4 is extremely weak, which however significantly strengthens on Ni doped Mg-4 cluster. Following the physisorption mechanism, NiMg3 cluster can adsorb three H-2 molecules at most and the cluster geometry plays an important role here. On the other hand, physisorption followed by chemisorption facilitates the growth of hydrogen adsorption process in both Mg-4 and NiMg3 clusters. Further, dissociation and diffusion of H-2 become more favourable on Ni doped Mg-4 cluster resulting in a larger number of H-2 adsorbed on NiMg3 compared to that on Mg-4. NiMg3 is found to exhibit practically attainable H-2 desorption energies lower than those for bare Mg-4 clusters.

Automated summary

In this study, hydrogen adsorption and dissociation on Mg-4 and NiMg3 clusters were investigated using the DFT method, revealing that Ni doping significantly enhances hydrogen physisorption on the clusters. The NiMg3 cluster can adsorb more H-2 molecules compared to Mg-4, with a lower H-2 desorption energy observed on NiMg3 clusters.