Narrowing band gap energy of CeO2 in (Ni/CeO2)@SiO2 catalyst for photothermal methane dry reforming

• (Ni/CeO 2 )@SiO 2 catalyst with tiny sizes of Ni and CeO 2 was synthesized. • Band gap energy of the catalyst was as narrow as 1.65 eV. • High photothermal MDR performance was obtained over the catalyst. • Sintering and carbon deposition were negligible for MDR reaction. Thermal catalysis is the most investigated approach for methane dry reforming (MDR) reaction over Ni-based catalysts. However, sintering and carbon deposition in the conventional approach tend to deactivate the Ni catalysts. Developing new technique to resolve the problems is a hot topic for MDR. Herein, we reported a novel (Ni/CeO 2 )@SiO 2 catalyst for MDR by photothermal catalysis. The catalyst was characterized by BET, XRD, TEM and UV–vis diffuse reflectance spectrum to analysis structural and optical properties, which were applied to build relationship with MDR performance. The results revealed that band gap energy of ceria in the catalyst was significantly narrowed by the tiny size of crystal ceria, leading to strong absorbance of visible solar light. The adsorption considerably promoted activations of CH 4 on Ni and CO 2 on CeO 2 , and greatly improved gasification of CH x at Ni-CeO 2 boundaries. Along with confinement effect from silica shell, sintering and carbon deposition were both resolved for the (Ni/CeO 2 )@SiO 2 catalyst in photothermal MDR. Consequently, photothermal MDR was higher and more stable than thermal MDR over the catalyst. The work provided a new way of photothermal MDR to enhance activity and stability, and simultaneously resolved problems of sintering and carbon deposition.