Enhancing Hydrogen Evolution Reaction Activity of Palladium Catalyst by Immobilization on MXene Nanosheets

Yiyang Sun, Jihyeong Lee, Nam Hee Kwon, Joohyun Lim, Xiaoyan Jin, Yury Gogotsi, Seong Ju Hwang

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Efficient catalysts with minimal content of catalytically active noble metals are essential for the transition to the clean hydrogen economy. Catalyst supports that can immobilize and stabilize catalytic nanoparticles and facilitate the supply of electrons and reactants to the catalysts are needed. Being hydrophilic and more conductive compared with carbons, MXenes have shown promise as catalyst supports. However, the controlled assembly of their 2D sheets creates a challenge. This study established a lattice engineering approach to regulate the assembly of exfoliated Ti3C2Tx MXene nanosheets with guest cations of various sizes. The enlargement of guest cations led to a decreased interlayer interaction of MXene lamellae and increased surface accessibility, allowing intercalation of Pd nanoparticles. Stabilization of Pd nanoparticles between interlayer-expanded MXene nanosheets improved their electrocatalytic activity. The Pd-immobilized K+-intercalated MXene nanosheets (PdKMX) demonstrated exceptional electrocatalytic performance for the hydrogen evolution reaction with the lowest overpotential of 72 mV (@10 mA cm-2) and the highest turnover frequency of 1.122 s-1 (@ an overpotential of 100 mV), which were superior to those of the state-of-the-art Pd nanoparticle-based electrocatalysts. Weakening of the interlayer interaction during self-assembly with K+ ions led to fewer layers in lamellae and expansion of the MXene in the c direction during Pd anchoring, providing numerous surface-active sites and promoting mass transport. In situ spectroscopic analysis suggests that the effective interfacial electron injection from the Pd nanoparticles strongly immobilized on interlayer-expanded PdKMX may be responsible for the improved electrocatalytic performance.

Original languageEnglish
Pages (from-to)6243-6255
Number of pages13
JournalACS Nano
Volume18
Issue number8
DOIs
StatePublished - 27 Feb 2024

Keywords

  • 2D materials
  • MXene
  • electrocatalyst
  • hydrogen evolution reaction (HER)
  • interfacial electronic coupling

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