Enhanced Photoelectrochemical Water Oxidation Using TiO₂-Co₃O₄ p-n Heterostructures Derived from in Situ-Loaded...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Exposing catalytically active metal sites in metal-organic frameworks (MOFs) is crucial for enhancing electron transport in electrochemical energy conversion.
• Maintaining MOF porosity is key to improving performance.

Purpose of the Study:

• To develop an in situ method for forming MOF-derived cobalt oxide (Co3O4) on titanium dioxide (TiO2) nanorods (NR).
• To investigate the effect of carbonization temperature on the photoelectrochemical water oxidation performance of TiO2-Co3O4 heterojunctions.

Main Methods:

• In situ MOF formation and loading onto TiO2 nanorods.
• Solution-processable method followed by annealing at various temperatures (350, 450, 550 °C).
• Characterization using XRD, XPS, FE-SEM, and HRTEM.

Main Results:

• Successful formation of TiO2-Co3O4 heterojunctions confirmed by characterization.
• The TiO2-Co3O4-450 sample exhibited an enhanced photocurrent of 2.4 mA/cm2, 2.6 times higher than pristine TiO2.
• Improved photocurrent attributed to p-n heterostructures promoting charge separation and transfer.

Conclusions:

• The ZIF-67 derived TiO2-Co3O4 photoanodes demonstrate high photoelectrochemical (PEC) water oxidation efficiency.
• Controlled carbonization of MOFs offers a pathway to synthesize low-cost, efficient electrocatalysts.