CO₂ reutilization for methane production via a catalytic process promoted by hydrides

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Rising carbon dioxide (CO2) emissions contribute significantly to global warming and the greenhouse effect.
• Developing effective technologies for CO2 mitigation and utilization is a critical global challenge.

Purpose of the Study:

• To demonstrate the selective recycling of CO2 into methane (CH4) using novel complex hydrides.
• To investigate the catalytic activity of magnesium-based metal hydrides (Mg2FeH6 and Mg2NiH4) as dual promoters and hydrogen sources for CO2 hydrogenation.

Main Methods:

• Utilized Mg2FeH6 and Mg2NiH4 complex hydrides as catalysts and hydrogen sources for CO2 hydrogenation.
• Conducted experiments at 400 °C, varying reaction times (5 h and 10 h) and H2:CO2 molar ratios.
• Analyzed reaction pathways, including the reversed water-gas shift reaction (WGSR) and CO methanation.

Main Results:

• Achieved total conversion of CO2 to CH4 using both Mg2FeH6 and Mg2NiH4 under specific conditions.
• Identified the formation of MgO as a byproduct due to CO2 activation and capture on the metal surface.
• Elucidated distinct reaction mechanisms for Mg2FeH6 (WGSR followed by methanation) and Mg2NiH4 (direct CO2 reduction).

Conclusions:

• Complex metal hydrides are effective dual promoters and hydrogen sources for CO2 recycling.
• This technology offers a viable pathway for converting CO2 into valuable fuels like methane.
• Optimizing hydride composition and reaction conditions is key for efficient CO2 conversion.