Design And Performance Study Of Hydrogen Evolution Electrocatalyst Based On Protonic Acid Ionic Liquid/Salt

Platinum is generally known as the most effective electrocatalyst for hydrogen evolution reaction since it can greatly lower the overpotential and accelerate the reaction kinetics,while its commercial potential always suffers from scarcity,high cost,low utilization and poor durability in the acidic electrolyte.Based on these disadvantages,we have optimized the current electrocatalytic hydrogen evolution from two aspects:（1）We demonstrate a facile method to improve the hydrogen evolution performance of Pt-based electrocatalysts by simply decorating the-state-of-the-art and commercially available Pt/C with hydrophobic protic（[DBU][NTf₂]）or aprotic（[BMIm][NTf₂]）ionic liquid.The current densities of[BMIm]@Pt/C and[DBU-H]@Pt/C with 10%ionic liquid at the overpotential of 40 m V are 2.81 and 4.15 times,respectively,higher than that of the pristine Pt/C.More importantly,ionic liquid-decoration significantly improves the long-term stability of Pt nanoparticles.After 8 h chronoamperometric measurement,[DBU-H]@Pt/C and[BMIm]@Pt/C can still retain 83.7%and 78.3%of the original activity,respectively,which are much higher than that of the pristine Pt/C（24.4%）.The improved performance of the Pt/C decorated with ionic liquid is considered to arise from the improved proton conductivity（particularly for protic ionic liquid）and hydrophobic microenvironment created by the supported ionic liquid phase.The presence of ionic liquid layer can not only de-coordinate H⁺from hydronium ions nearby the Pt nanoparticles,but also protect Pt nanoparticles from dissolution in the acidic media.（2）A free-standing HER electrode,phosphorous-doped molybdenum nitride nanoparticles embedded in 3-dimentional carbon nanosheet matrix（P-Mo₂N-CNS）fabricated via one-step carbonization and in-situ formation was reported for replacing Pt/C.The as-prepared catalyst shows free-standing architecture with interconnected porous microstructure.P-doped Mo₂N nanoparticles with an average diameter of 4.4nm are well embedded in the 3-dimentional vertical carbon nanosheets matrix.Remarkable electrocatalytic HER performance is observed in alkaline,neutral and acidic media at large current densities.The overpotential of P-Mo₂N-CNS to drive a current density of 100 m A/cm² in 0.5 M H₂SO₄ and 1.0 M PBS is only 181 and 221 m V,respectively.In particular,the current density reaches up to 1000 m A/cm² at a low overpotential of 256 m V in 1.0 M KOH,much better than that of the commercial Pt/C catalyst.Density functional theory calculations suggest the optimized H sorption kinetics on Mo₂N after P doping,elucidating the superior activity.