Dy3Al2(AlO4)3 ceramic nanogarnets: Sol-gel auto-combustion synthesis, characterization and joint experimental and computational structural analysis for electrochemical hydrogen storage performances

A single crystal Dy₃Al₂(AlO₄)₃ rare-earth nanogarnets were grown via a sol-gel combustion method using single fuel. The structure and purity of nanogarnets was confirmed by XRD analysis. The average crystallite sizes and the effective particle sizes were calculated by Scherrer and Hall-Williamson equations. The FTIR results clearly confirmed the formation of metal-oxygen and metal-metal bonds of the product. The morphological studies were affirmed the nanoscale formation of Dy₃Al₅O₁₂ with approximately narrow distribution of the particles. The direct band gap energy of the nanogarnets was calculated using Tauc equation about 3.33 eV. To complement the experimental data, the structural and electronic properties were calculated using periodic density functional theory. The use of the Hubbard U parameter was used and improved the band gap to experimental values. Experimental and computational observations have rendered the Dy₃Al₅O₁₂ nanogarnets can be suitable for hydrogen energy sorption. The electrochemical hydrogen storage capacity of Dy₃Al₅O₁₂ was measured at about 3137 mAh/g after 15 cycles.