First-principles investigation of rhodium hydrides under high pressure

Hydrogen-rich compounds are being extensively explored theoretically and experimentally as potential hydrogen storage materials. In this work, we predicted a hydrogen-rich compound rhodium trihydride (RhH3) with a high volumetric hydrogen density of 212.5 g/L by means of ab initio calculations. The RhH3 with Pnma symmetry is thermodynamically stable and accessible through synthesis above 40 GPa. The compound is dynamically and mechanically stable at ambient pressure. Further calculation suggests a probable dehydrogenation temperature T-des of 65 degrees C at ambient pressure with decomposition route to Rh + H-2. High volumetric hydrogen density and moderate dehydrogenation temperature place RhH3 as one of the best hydrogen storage materials. Our work encourages the experimental synthesis of RhH3 at high pressure.

Automated summary

Hydrogen-rich compound Rhodium Trihydride (RhH3) is predicted to have a high volumetric hydrogen density of 212.5 g/L and a moderate dehydrogenation temperature of 65 degrees C, making it one of the best hydrogen storage materials. Experimental synthesis of RhH3 at high pressure is encouraged based on the calculations.