MOF-derived CoO_x/MgO dual modification boosting hematite photoelectrocatalysis

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) offer high surface area for photoelectrochemical (PEC) applications but face challenges in charge transport and active site utilization.
• MOF-derived materials present a promising strategy to overcome these limitations in PEC devices.
• Iron oxide (Fe2O3) is a common photoanode material with potential for improvement.

Purpose of the Study:

• To design and fabricate an efficient photoelectrochemical (PEC) photoanode using MOF-derived materials.
• To enhance the performance of Fe2O3-based photoanodes by incorporating a cobalt oxide (CoO_x) co-catalyst and a magnesium oxide (MgO) interlayer.
• To investigate the synergistic effects of CoO_x and MgO on charge transfer, active site utilization, and overall PEC performance.

Main Methods:

• Rational design of a CoO_x/MgO/Fe2O3 photoanode architecture.
• In situ derivation of CoO_x from ZIF-67 (a MOF) as a co-catalyst.
• Integration of an MgO hole-transport interlayer.
• Fabrication and characterization of the composite photoanode.

Main Results:

• The CoO_x/MgO/Fe2O3 photoanode achieved a photocurrent density of 0.50 mA cm-2 at 1.23 V vs. RHE.
• This represents a 2.5-fold enhancement compared to pristine Fe2O3.
• Characterization confirmed that MgO facilitates hole transfer and improves band bending, while MOF-derived CoO_x provides abundant active sites.
• The architecture demonstrated significantly improved charge injection and separation efficiencies.

Conclusions:

• The rationally designed CoO_x/MgO/Fe2O3 architecture effectively enhances photoelectrochemical performance.
• The combination of MOF-derived co-catalysts and interlayers is a viable strategy for improving PEC devices.
• This work offers a pathway towards more efficient and stable photoanode materials for energy conversion applications.