Karfa, Paramita Majhi, Kartick C. Madhuri, Rashmi Shape-Dependent Electrocatalytic Activity of Iridium Oxide Decorated Erbium Pyrosilicate toward the Hydrogen Evolution Reaction over the Entire pH Range The synthesis of iridium oxide decorated erbium pyrosilicate (Er<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>:IrO<sub>2</sub>) was performed by a simple sol–gel technique. By simple alteration of the reaction parameters, different shapes (i.e., cubes, rods, large spheres, small spheres, and sheets) of Er<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>:IrO<sub>2</sub> were obtained and their catalytic activities were tested toward the hydrogen evolution reaction (HER). Among the different morphologies of Er<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>:IrO<sub>2</sub>, cube-shaped nanoparticles (Er<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>:IrO<sub>2–5</sub>) with sharp edges provided promising HER activity over a wide pH range from 0 to 14 in acidic, neutral, and basic media. Er<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>:IrO<sub>2–5</sub> exhibited an onset potential of −0.076 V with a very high current density of 252 mA cm<sup>–2</sup> (at −0.54 V). The overpotential and Tafel slope for the HER using Er<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>:IrO<sub>2–5</sub> were found to be 130 mV and 49 mV/dec, 170 mV and 59 mV/dec, and 190 mV and 67 mV/dec in 0.5 M H<sub>2</sub>SO<sub>4</sub>, 1.0 M KOH, and 2.0 M PBS, respectively. The low cost, highly active electrocatalyst shows robust durability over acidic medium for nearly 250 min. Such a superior catalytic activity can be attributed to the synergistic effect between IrO<sub>2</sub> and erbium pyrosilicate, in which the 4f orbital (not fully occupied) of rare-earth elements may have occupied the 5d orbital and become valence electrons, resulting in the improved HER activity. Entire pH Range;Er 2 Si 2 O 7;Hydrogen Evolution Reaction;HER activity;1.0 M KOH;Shape-Dependent Electrocatalytic Activity;hydrogen evolution reaction;0.5 M H 2;erbium pyrosilicate;mV;2.0 M PBS;IrO 2 2018-08-23
    https://acs.figshare.com/articles/journal_contribution/Shape-Dependent_Electrocatalytic_Activity_of_Iridium_Oxide_Decorated_Erbium_Pyrosilicate_toward_the_Hydrogen_Evolution_Reaction_over_the_Entire_pH_Range/7006058
10.1021/acscatal.8b01363.s001