Silicalite-Supported Ni Catalysts for Efficient CO₂ Conversion into CH₄.

Area of Science:

• Catalysis and Materials Science
• Environmental Chemistry
• Sustainable Energy

Background:

• Carbon dioxide (CO2) emissions contribute significantly to global warming.
• Catalytic conversion of CO2 into methane (CH4) presents a promising pathway for CO2 utilization and climate change mitigation.
• Nickel-based catalysts supported on zeolites like silicalite-1 are investigated for this transformation.

Purpose of the Study:

• To synthesize and characterize silicalite-1 supported Ni catalysts with varying Ni loadings.
• To evaluate the performance of these catalysts in CO2 conversion to CH4.
• To understand the effect of Ni loading on catalyst structure, properties, and catalytic activity.

Main Methods:

• Wet impregnation method was used to prepare Ni@Silicalite-1 catalysts with different Ni loadings.
• X-ray diffraction (XRD) and N2 sorption techniques were employed for catalyst characterization.
• Catalytic performance was assessed by measuring CO2 conversion and CH4 selectivity at various temperatures and pressures.

Main Results:

• Higher Ni loadings led to increased crystallite size and decreased specific surface area and microporosity.
• Ni(5)@Silicalite-1 demonstrated higher CO2 conversion efficiency compared to Ni(10)@Silicalite-1 across tested temperatures.
• The NiO(5)@Silicalite-1 catalyst achieved a maximum CO2 conversion of 88% at 450 °C, with CH4 selectivity remaining consistent across catalysts.

Conclusions:

• The performance of Ni@Silicalite-1 catalysts in CO2 to CH4 conversion is influenced by Ni loading.
• Lower Ni loading (5 wt.%) resulted in superior catalytic activity, attributed to smaller NiO crystallites and improved textural properties.
• Silicalite-1 supported Ni catalysts show potential for efficient CO2 utilization in methane production.