Synthesis of Er 2Ti 2O 7 nanocrystals and its electrochemical hydrogen storage behavior

Abstract

Ultrafine Er 2Ti 2O 7 was synthesized at 700 °C within 2 h by a soft-chemistry route named citric acid sol–gel method (CAM). The obtained Er 2Ti 2O 7 with high dispersibility was square-like and the average size was about 70 nm. The prepared Er 2Ti 2O 7 nanocrystals in 6 M KOH aqueous solutions were investigated as a hydrogen storage material. It was found that the Er 2Ti 2O 7 powders would function as electrochemical hydrogen storage, showed fair electrochemical reversibility, and considerably high charge–discharge capacity. The reversible discharge capacity of the Er 2Ti 2O 7 electrode was found to exceed 320 mAh/g and adsorption capability of hydrogen is up to 1.27% at a current rate of 100 mA/g. In addition, the cycling ability and high rate capability of the Er 2Ti 2O 7 electrode are fairly good with only 4% capacity decay after 25 cycles. Cyclic voltammograms (CVs) were carried out to further examine the electrochemical hydrogen storage mechanism of Er 2Ti 2O 7.