Modulation in the d Band of Ir by Core–Shell Construction for Robust Water Splitting Electrocatalysts in Acid

Abstract

The realization of commercialization of proton electrolyte membrane water splitting technology significantly depends on the anodic electrocatalyst working at a high potential and strong acidic conditions requiring superior oxygen evolution reaction activity and stability. In this work, we devise the construction of ultrasmall Pd@Ir core−shell nanoparticles (5 nm) with atomic layer Ir (3 atomic layers) on carbon nanotubes (Pd@Ir/CNT) as an exceptional bifunctional electrocatalyst in acidic water splitting. Due to the core−shell structure, strain generated at heterointerfaces leads to an upshifted d band center of Ir atoms contributing to a 62-fold better mass activity at 1.63 V vs RHE than commercial IrO 2 ; besides, the electronic hybridization suppresses the electrochemical dissolution of Ir; as a result, robust stability is also achieved. In hydrogen evolution reaction catalysis, Pd@Ir/CNT exhibits a 3.7 times higher mass activity than Pt/C. Furthermore, only 1.7 V is required to reach a water splitting current density of 100 mA cm −2 , 251 mV lower than that of Pt/ C−IrO 2 , indicating its superiority in acidic water splitting.

Engineering the electronic structure of sub-nanometric Ru clusters via Pt single-atom modification for highly efficient electrocatalytic hydrogen evolution

“…With the assistance of Pt SA, the 3 d of Ru 1 atom in the CNPA-PtRu model reveals higher occupation than CNPA-Ru near the Fermi level, which indicates the strong adsorption capability of reaction intermediates during HER catalysis. 57,58 To understand how the electronic structure change of Pt SA affects the sub-nanometric Ru cluster, differential charge density analysis was carried out. The obvious charge density redistribution at the junction of Pt and Ru atoms is observed in Fig.…”

Optimizing Pt-Based Alloy Electrocatalysts for Improved Hydrogen Evolution Performance in Alkaline Electrolytes: A Comprehensive Review

“…The strain causes the d-band center of the catalyst to shift with respect to the Fermi level. Specifically, the upshift of the d-band center will change the overlap with the hydrogen σ* orbital and the strength of the metal–H bond, thereby regulating the adsorption and desorption of the adsorbate. , The downshift of the d-band center reduces the adsorption energy of the H intermediate and promotes the desorption of hydrogen from the catalyst surface. , Strain can also reduce the band gap and improve the conductivity up to the point to trigger a semiconductor-to-metal transition …”

Molecular Mechanisms of Oxygen Evolution Reactions for Artificial Photosynthesis

“…Due to the core-shell structure, strain generated at heterointerfaces leads to an up-shifted d band center of Ir atoms contributing to a 62-fold better mass activity than commercial IrO 2 . Moreover, electronic hybridization suppresses the electrochemical dissolution of Ir, resulting in the achievement of robust stability [159].…”