Role of lanthanum oxycarbonate in dendritic fibrous Ni/CHE-La catalyst on enhanced CO₂dissociation for low-Temperature CO₂reforming of methane

Catalyst design of low temperature CO2 reforming of methane for sustainable energy production is essential to overcome the activation energy barrier of its stable CO2 and CH4 reactant gases, metal sintering and coke poisoning. Herein, we report the development of fibrous lanthanum silica synthesized via microemulsion seed crystallization loaded with nickel oxide metal through wetness impregnation (Ni/CHE-La). The incorporation of lanthanum in the fibrous dendritic Ni/CHE-La reportedly contributed to strong metal-support interaction benefiting its metal anti-sintering properties as proven by FTIR spectroscopy, H2-TPR, HRTEM and XPS. Ni/CHE-La was also compared with Ni/KCC-1 and structurally unmodified Ni/SiLa to determine the content of surface reactive oxygen species and its influence on its catalytic activity under integral reaction conditions in the temperature interval of 400-800 °C. The XPS measurements demonstrated the amount of surface reactive oxygen associated as oxygen vacancies decreases in the following order (Ni/CHE-La > Ni/KCC-1> Ni/SiLa). The catalytic activity of all three catalysts followed similar trend, highlighting the synergistic benefits of lanthanum oxycarbonate and surface reactive oxygen species on the fibrous lanthanum silica promoted the dissociation of CO2 into CO and lowered the CH4 apparent activation energy barrier. The regeneration study showed Ni/CHE-La possessed a highly stable reaction after 18h at 600 °C. Further post-reaction study revealed its high anti-sintering resistance and anti-coking properties which could be assigned to the enhanced CO2 dissociation driven by lanthanum oxycarbonate phase on the catalytic surface for the removal of carbon deposits.