Frank Partial Dislocations in Coplanar Ir/C Ultrathin Nanosheets Boost Hydrogen Evolution Reaction

Abstract Developing highly active and stable acidic hydrogen evolution catalysts is of great significance and challenge for the long‐term operation of commercial proton exchange membrane (PEM) electrolyzers. In this work, coplanar ultrathin nanosheets composed of rich‐Frank partial dislocations (FPDs) are first synthesized. Ir nanoparticles and carbon (Dr‐Ir/C NSs) use a nonequilibrium high‐temperature thermal shock method (>1200 °C) and KBr template‐assisted techniques. Dr‐Ir/C NSs exhibit excellent hydrogen evolution reaction (HER) performance with a remarkably high mass activity of 6.64 A mg −1 at 50 mV, which is among the best Ir‐based catalysts.In addition, Dr‐Ir/C NSs are able to operate stably at 1.0 A cm −2 for 200 h as a cathode in a PEM electrolyser, and the original coplanar ultrathin nanosheets structure are maintained after the test, demonstrating excellent stability against stacking and agglomeration. Geometrical phase analysis and theoretical calculations show that the FPDs produce a 4% compressive strain in the Dr‐Ir/C NSs, and the compressive strain weaken the adsorption of H* by Ir, thus increasing the intrinsic activity of the catalyst.