Constructing Z-Scheme Ni-MOF-74/CoAl-Layered Double Hydroxide Heterojunctions for Enhanced Photocatalytic CO₂...

Area of Science:

• Materials Science
• Photocatalysis
• Nanotechnology

Background:

• Z-scheme heterojunctions are vital for efficient photocatalysis, improving charge separation and reducing power loss.
• Controlling morphology and electronic structure in heterojunctions is key to enhancing photocatalytic activity.
• Nickel-based metal-organic frameworks (Ni-MOF-74) offer unique structural properties for template-directed synthesis.

Purpose of the Study:

• To develop a novel Z-scheme heterojunction for enhanced photocatalytic CO2 reduction.
• To precisely control the morphology and interfacial electronic structure of ultrathin nanosheets.
• To elucidate the charge transfer mechanism and CO2 conversion pathway.

Main Methods:

• Fabrication of ultrathin CoAl-LDH nanosheets using Ni-MOF-74 as a structural template.
• Characterization using X-ray photoelectron spectroscopy (XPS) to confirm charge transfer.
• In situ Fourier transform infrared spectroscopy and Soft X-ray absorption spectroscopy to study reaction intermediates and pathways.

Main Results:

• The synthesized 20-NiL heterojunction exhibited a CO production rate of 79.86 μmol·g-1·h-1, a 70% enhancement over pristine components.
• XPS analysis confirmed electron transfer from CoAl-LDH to Ni-MOF-74, characteristic of a Z-scheme mechanism.
• In situ spectroscopy identified COOH* and CO* as dominant intermediates in the 2e- pathway for CO2 to CO conversion.

Conclusions:

• The developed Z-scheme heterojunction strategy effectively enhances photocatalytic CO2 reduction.
• Precise control over material morphology and electronic structure is crucial for photocatalyst performance.
• This research provides insights into charge transfer kinetics and reaction mechanisms for CO2 conversion.