Light-promoted synergy between CO2 adsorption sites and active oxygen leads to efficient photothermocatalytic dry reforming of methane on Ni/Ni-Sr-Al2O3

Abstract

Photothermal catalytic dry reforming of methane (DRM) technology opens up a highly potential pathway for converting solar energy into fuels. However, achieving high fuel production rates often requires extremely high light intensities and is accompanied by unfavorable coking side reactions. In response to these challenges, this study successfully synthesized a composite material consisting of nickel nanoparticles (Ni NPs) supported on Ni and Sr co-doped alumina, named Ni/Ni-Sr-Al₂O₃. Under comparatively low light intensity conditions (80.0 kW m⁻²), this composite material exhibited exceptional photothermal catalytic activity. Specifically, the production rates of hydrogen (r_H2) and carbon monoxide (r_CO) achieved 114.2 mmol min⁻¹ g⁻¹ and 129.4 mmol min⁻¹ g⁻¹, respectively, with an efficiency (η) increased to 30.6 %. Compared to a reference catalyst of Ni/Al₂O₃, the Ni/Ni-Sr-Al₂O₃ catalyst shows a 29.6-fold increase in coking resistance. The high efficiency of Ni/Ni-Sr-Al₂O₃ in DRM catalysis is attributed to a light-promoted synergy between CO₂ adsorption sites due to Sr doping and active oxygen due to Ni doping, both of which participate in the oxidation of carbon species (formed by decomposition of methane on Ni nanoparticles). This not only increases catalytic activity, but also significantly inhibits the polymerization of carbon species into coke.