3D Yolk@Shell TiO_{2- x}/LDH Architecture: Tailored Structure for Visible Light CO₂ Conversion

Area of Science:

• Materials Science
• Catalysis
• Renewable Energy

Background:

• Global warming necessitates sustainable energy solutions.
• Photoconversion of carbon dioxide (CO2) into hydrocarbon solar fuels is a promising approach.
• Engineered semiconductors offer potential for efficient CO2 photoreduction.

Purpose of the Study:

• To develop a novel 3D yolk@shell hydrogenated TiO2/Co-Al layered double hydroxide (3D Y@S TiO2-x/LDH) architecture.
• To evaluate its efficiency for CO2 photoreduction into solar fuels without noble metal cocatalysts.
• To understand the structure-property relationships governing the enhanced catalytic performance.

Main Methods:

• Sequential solvothermal, hydrogen treatment, and hydrothermal preparation methods were employed.
• Synthesis of a three-dimensional yolk@shell TiO2-x/LDH nanostructure.
• Time-dependent photoreduction experiments to quantify fuel production.

Main Results:

• The 3D Y@S TiO2-x/LDH architecture demonstrated high efficiency for CO2 photoreduction.
• Selective methanol (CH3OH) production observed initially, followed by gradual methane (CH4) production over time.
• Achieved production rates of 251 μmol/gcat. h for CH3OH and 63 μmol/gcat. h for CH4.
• No noble metal cocatalyst was required for high performance.

Conclusions:

• The engineered 3D Y@S TiO2-x/LDH architecture exhibits excellent CO2 sorption and catalytic activity.
• Oxygen vacancies and Ti3+ ions in TiO2-x enhance CO2 activation and conversion.
• Improved charge separation and reduced band gap contribute to visible-light-driven photocatalysis.
• This material presents a viable pathway for sustainable solar fuel production from CO2.