The usage of fossil fuels has resulted in enormous CO2 emissions, which have led to a number of environmental problems and climate change. The hydrogenation of CO2 to hydrocarbon fuels and chemicals is emerging as a potential process for reducing carbon footprint and storing renewable energy, driven by the rapid development of green hydrogen and CO2 capture technology. In mild settings, photothermal catalysis makes efficient CO2 conversion possible.
The enhanced LSPR effect on NiFeAl for effective photothermal catalysis of CO2 methanation. Image Credit: Science China Press
In a study conducted by Professors Kang Cheng and Ye Wang from the College of Chemistry and Chemical Engineering at Xiamen University, catalysts were assessed using a quartz reactor with a square cavity in the middle that allowed light to enter under high pressure. The study was published in the journal Science China Chemistry,
Using the urea-assisted precipitation approach, various NiFe alloy photothermal catalysts were produced for CO2 methanation. The best catalytic activity was shown by bimetallic NiFe nanoparticles with a Ni/Fe atomic ratio of 7 and Al2O3 serving as the structural promoter.
Without external heating, the CO2 conversion rate can approach 98 % and the CH4 selectivity can reach 99 %. Over 100 hours of stable operation are possible with the catalyst. The NiFe alloy's LSPR action was shown to be enhanced by the NiFeAl catalyst's unique layered structure and small alloy particle size (~21 nm) when compared to other catalysts.
NiFe alloys can synergistically promote CO2 methanation when compared to Ni or Fe alloys. An infrared camera recording light irradiation revealed that the catalyst's surface temperature reached as high as 356 °C, suggesting that the catalyst was effective in converting light energy into thermal energy.
The idea for the structural design of a photothermal catalyst was also presented in this study, along with the preparation of an effective catalyst for CO2 methanation.
Journal Reference:
Li, J., et.al., (2023). Efficient photothermal CO2 methanation over NiFe alloy nanoparticles with enhanced localized surface plasmon resonance effect. Science China Chemistry. doi.org/10.1007/s11426-023-1876-4.