Uncovering the Origin of Light‐Promoted Synergetic Effect and Y Doping in Enhancing Photothermocatalytic Dry Reforming of Methane on Ni/Ni‐Y2‐Al2O3

Photothermocatalytic dry reforming of methane (DRM) can convert CH 4 and CO 2 into syngas, offering an effective approach to reducing greenhouse gas emissions. However, photothermocatalytic DRM reaction generally needs a high light intensity surpassing 192 kW m −2 to attain high light‐fuel conversion. Also, catalysts applied to photothermocatalytic DRM are liable to inactivation due to carbon deposition. Herein, a nanocomposite of Ni nanoparticles supported on Ni‐ and Y‐doped Al 2 O 3 (Ni/Ni‐Y 2 ‐Al 2 O 3 ) is prepared. It achieves high H 2 and CO production rates with a light‐to‐fuel efficiency (29.2%) at a lower intensity (80.1 kW m −2 ). Meanwhile, it sustains excellent photothermocatalytic durability and accomplishes a 37‐fold reduction in carbon deposition rate compared to Ni/Al 2 O 3 . The substantially enhanced catalytic activity and carbon resistance of Ni/Ni‐Y 2 ‐Al 2 O 3 are correlated with accelerating carbon species (C*) oxidation (the rate‐determining steps of DRM). This acceleration derives from the synergetic effect and carbonate species resulting from Y doping, which participate in C* oxidation via two separate reaction pathways. When in light, the synergetic effect further facilitates C* oxidation. Simultaneously, light immensely reduces activation energy, activates the NiO bonds at the interface region, and expedites the reaction between carbonate species and C* in the interface, enhancing catalytic activity and carbon resistance.