Oxygen Vacancy Injection on (111) CeO₂ Nanocrystal Facets for Efficient H₂O₂ Detection

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Facet and defect engineering are crucial for enhancing cerium oxide (CeO2) catalytic performance.
• Inconsistent reports on facet-oxygen vacancy synergy and limited studies on heavily doped vacancies necessitate further investigation.

Purpose of the Study:

• To synthesize CeO2 nanocrystals with controlled facets and abundant oxygen vacancies.
• To investigate the synergistic effects of crystal facets and heavily doped oxygen vacancies on electrochemical sensing.
• To explore the distinct roles of oxygen vacancies on different CeO2 facets.

Main Methods:

• Synthesis of CeO2 nanocrystals with selectively exposed facets (octahedron, cube, sphere, rod).
• Fabrication of electrochemical sensors utilizing these engineered nanocrystals.
• Electrochemical characterization to evaluate sensing performance, selectivity, repeatability, and stability.

Main Results:

• CeO2 nanocrystals with different facets exhibited contrasting electrochemical behaviors, confirming distinct oxygen vacancy roles.
• CeO2 octahedrons with heavily doped (111) facets demonstrated optimal non-enzymatic H2O2 sensing.
• Achieved high sensitivity (128.83 µA mM⁻¹ cm⁻²), broad linear range (20 µM–13.61 mM), and low detection limit (1.63 µM).
• Demonstrated sensor feasibility in medical disinfectants.

Conclusions:

• The synergistic effect between facets and heavily doped oxygen vacancies significantly impacts CeO2 electrochemical sensing.
• The (111) facet on thermodynamically stable CeO2 octahedrons provides superior performance for H2O2 detection.
• This research offers insights into crystal surface engineering for advanced sensor development.