Defects of thin CaO(001) on Mo(001): an EPR spectroscopic perspective

Richter, Nina F.; Risse, Thomas

doi:10.1039/d2cp00389a

Cited by 3 publications

(1 citation statement)

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“…Electron paramagnetic resonance (EPR) spectroscopy was conducted to verify the structures of defects in d-Mo 2 Ti 2 C 3 T x and Mo 2 Ti 2 C 3 T x because they are sensitive to unpaired electrons in materials. Mo 2 Ti 2 C 3 T x displays a signal at a g value of 2.002, corresponding to intrinsic oxygen vacancy on the oxidized surfaces, as presented in Figure c. , After etching by NMP to create defects, d-Mo 2 Ti 2 C 3 T x exhibits a signal at a g value of 1.970. It indicates the successful construction of Mo vacancies into MXene nanosheets, owing to the preferential exposure of the Mo atomic layer on the Mo 2 Ti 2 C 3 T x MXene.…”

Section: Resultsmentioning

confidence: 99%

Immobilizing Ultralow Loading Platinum Nanoparticles onto MXene through Defect Engineering to Enhance the Activity of the Hydrogen Evolution Reaction

Xu,

Huang,

Yue

et al. 2024

ACS Appl. Energy Mater.

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Developing low-cost, highly active, and durable electrocatalysts for the hydrogen evolution reaction (HER) in acidic medium is essential for achieving the large-scale utilization of proton exchange membrane water electrolyzers. It has been demonstrated that non-precious-metal electrocatalysts are unable to substitute the most efficient platinum in a short period. Consequently, the fabrication of Pt-based heterogeneous electrocatalysts with ultralow loading and ultrahigh Pt utilization efficiency becomes a practical approach. Herein, an approach is reported to immobilize ultralow loading (∼0.26 wt %) Pt NPs to Mo vacancies on the surface of Mo 2 Ti 2 C 3 T x MXene. Because of the anchoring by Mo vacancies and the vast surface area of MXene, defect enriched Mo 2 Ti 2 C 3 T x supported Pt nanoparticles (Pt NPs/d-Mo 2 Ti 2 C 3 T x ) possess ultrasmall particle sizes (∼2.1 nm) and increased dispersity of Pt NPs. As a result, the as-prepared Pt NPs/d-Mo 2 Ti 2 C 3 T x reaches a current density 100 mA cm −2 at an overpotential of 123 mV. When compared to Pt/C (20 wt %), the mass activity of Pt on Pt NPs/d-Mo 2 Ti 2 C 3 T x is found to be 134 times higher. Meanwhile, it presents a high turnover frequency (8.49 H 2 s −1 at overpotential of 50 mV) and fast kinetics (a Tafel slope of 30.1 mV dec −1 ) as well as high durability (maintaining the current density of 100 mA cm −2 for more than 15 h). Theoretical simulations reveal that transferring electrons from Mo atoms regulated the d-band electronic structure of Pt NPs, resulting in a stronger interaction with adsorbed H species and ultimately boosting the HER activity.

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Section: Resultsmentioning

confidence: 99%