Surface-Controlled TiO₂ Nanocrystals with Catalytically Active Single-Site Co Incorporation for the Oxygen Evolution...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Designing efficient electrocatalysts is challenging due to difficulties in identifying and controlling active sites in heterogeneous materials.
• The oxygen evolution reaction (OER) is crucial for energy conversion technologies but requires highly active and stable catalysts.

Purpose of the Study:

• To synthesize single-site cobalt catalysts substitutionally doped into surface-controlled TiO2 anatase nanocrystals.
• To enhance the catalytic activity for the oxygen evolution reaction (OER).
• To investigate the influence of cobalt coordination environment and TiO2 surface facets on OER kinetics.

Main Methods:

• Synthesis of surface-controlled TiO2 anatase nanocrystals with selectively exposed facets.
• Doping single-site cobalt (Co) into TiO2 nanocrystals.
• Computational modeling using grand canonical quantum mechanics to study OER mechanisms and kinetics.
• Electrochemical characterization to evaluate OER performance, including current densities and turnover frequencies.

Main Results:

• Quantum mechanics calculations predicted higher OER turnover frequencies for Co doped into the TiO2 (001) surface compared to the (101) surface.
• Experimental results confirmed enhanced OER activity for Co-doped TiO2 nanoplates with exposed {001} surfaces.
• Co-doped TiO2 nanobipyramids with exposed {101} surfaces showed lower OER performance.

Conclusions:

• The coordination environment of Co and the exposed surface facets of TiO2 significantly influence OER kinetics.
• Precision synthesis and theoretical calculations are synergistic tools for developing advanced electrocatalysts.
• Single-site Co catalysts on TiO2 with controlled surface facets offer a promising pathway for efficient OER catalysis.