A Novel Synergetic Effect and Photoactivation Lead to Very Effective UV–Visible–Infrared Light‐Driven Photothermocatalytic CO2 Reduction with CH4 on Ni/Ni‐Doped Al2O3

Abstract

A nanocomposite of Ni nanoparticles (NPs) loaded on Ni‐doped Al2O3 (Ni/Ni‐Al2O3) is prepared. Very effective photothermocatalytic dry reforming of methane (DRM) is acquired by Ni/Ni‐Al2O3 under focused UV–vis–IR illumination with a relatively low light intensity of 80.7 kW m−2. Under focused UV–vis–IR illumination, Ni/Ni‐Al2O3 has high production rates of H2 (, 72.62 mmol g−1 min−1) and CO (rCO, 88.29 mmol g−1 min−1) as well as a large light‐to‐fuel efficiency (η) of 28.0%. Compared with a reference catalyst of Ni NPs loaded on Al2O3 (Ni/Al2O3), the photothermocatalytic activity and η of Ni/Ni‐Al2O3 are enhanced and its photothermocatalytic durability is significantly improved due to its coking rate being dramatically decreased by 42.5 times. This is attributed to a synergistic effect between Ni NPs and Ni‐Al2O3: the active oxygen of Ni‐Al2O3 participates in the oxidation of carbon species as one of decisive steps for DRM, thus not only improving the catalytic activity, but also dramatically promoting coking resistance. It is found that light not only plays a heating role, but also substantially reduces the activation energy of DRM, thus improving the catalytic activity and coking resistance due to the great acceleration of carbon oxidation upon focused illumination (photoactivation).