Lewis‐Acidic PtIr Multipods Enable High‐Performance Li–O₂ Batteries

Abstract

The sluggish oxygen reaction kinetics concomitant with the high overpotentials and parasitic reactions from cathodes and solvents is the major challenge in aprotic lithium‐oxygen (Li–O2) batteries. Herein, PtIr multipods with a low Lewis acidity of the Pt atoms are reported as an advanced cathode for improving overpotentials and stabilities. DFT calculations disclose that electrons have a strong disposition to transfer from Ir to Pt, since Pt has a higher electronegativity than Ir, resulting in a lower Lewis acidity of the Pt atoms than that on the pure Pt surface. The low Lewis acidity of Pt atoms on the PtIr surface entails a high electron density and a down‐shifting of the d‐band center, thereby weakening the binding energy towards intermediates (LiO2), which is the key in achieving low oxygen‐reduction‐reaction (ORR) and oxygen‐evolution‐reaction (OER) overpotentials. The Li–O2 cell based on PtIr electrodes exhibits a very low overall discharge/charge overpotential (0.44 V) and an excellent cycle life (180 cycles), outperforming the bulk of reported noble‐metal‐based cathodes.

Strategic Modulation of Target-Specific Isolated Fe,Co Single-Atom Active Sites for Oxygen Electrocatalysis Impacting High Power Zn–Air Battery

“…However, in ORR, the OOH* determining the PDS is well established. 66 One of the reasons for the reduction of overpotential for OER and ORR in the Fe,Co,N−C case could be attributed to the downward shift of the d-band center and thus weaker adsorption of the reaction intermediates relative to the d-band center in Co,N−C/Fe,N− C. 67,68 This study can be further explored in terms of critical distance between the two metal atoms and corresponding catalytic activity. Also, we have estimated the overpotentials for both reactions on complementary metal sites, i.e., OER on Fe and ORR on Co.…”

Equilibrated PtIr/IrOx Atomic Heterojunctions on Ultrafine 1D Nanowires Enable Superior Dual‐Electrocatalysis for Overall Water Splitting

“…Meanwhile, compared to the standard Pt 4f 7/2 (71.0 eV) and Ir 4f 7/2 (60.8 eV), [ 25,29 ] the up‐shifted binding energies of Pt 0 and Ir 0 on PtIr/IrO x ‐30 and PtIr/IrO x ‐50 NWs suggests the partial charge losing for metallic Pt and Ir, due to the surface IrO x species may play as the Lewis acid for accumulating electrons as the interfaces. [ 31,32 ] With respect to the O 1 s (Figure 2c), the binding energies of 534.0 and 532.5 eV typically assigned to hydroxyl species and adsorbed oxygen‐containing species. [ 33 ] Moreover, an additional peak around 531.0 eV, [ 34 ] which is ignorable on the pure Pt NWs, can be distinctly observed and assigned to lattice oxygen bonded to metal (Ir–O) on the samples of Ir/C, PtIr/IrO x ‐30 NWs, and PtIr/IrO x ‐50 NWs, further confirming the favorable in situ oxidation of Ir on the ultrafine NWs.…”

Ultrafine platinum-iridium distorted nanowires as robust catalysts toward bifunctional hydrogen catalysis

“…The negatively shift was likely due to the higher electronegativity of Pt than Ir. 50 The binding energy of different Pt–Ir DNWs/C showed a gradually increasing trend with the increase in Ir content, indicating that the electrons transfer from Ir to Pt (Fig. 4a).…”