Local surface plasmon resonance promotion of photogenerated electrons to hot electrons for enhancing photothermal CO2 hydrogenation over Ni(OH)2/Ti3C2 catalysts

Although photothermal catalysis is currently used to enhance carbon dioxide (CO2) hydrogenation, it is challenging to gain an in-depth understanding of the enhancement involved in this process. Ni(OH)2/Ti3C2 (NiTC) photothermal catalysts were prepared using an acid–base etching–hydrothermal method. β-Ni(OH)2 was loaded on the surface of Ti3C2 and inserted between the layers to generate a built–in electric field (BIEF) at the interface of Ni(OH)2 and Ti3C2. The strong coupling between plasmonic Ti3C2 and Ni(OH)2 results in NiTC exhibiting surface plasmonic transverse electric resonance (TE) and transverse magnetic resonance (TM) waves, as well as the enhanced absorption peak. The local surface plasmon resonance (LSPR) effect occurs when Ti3C2 and Ni(OH)2 are excited by visible–near infrared light, while the spectral overlap of the two produces enhances the TM waves. The enhanced TM waves of Ti3C2 “pump” photogenerated electrons to transform them into hot electrons to replenish Ti3C2 via Landau damping and the BIEF. More hot electron generation enhances the photothermal CO2 conversion. The average photothermal CO2 conversion is 0.89 mmol·gcat.–1·h–1 over NiTC composite at 250 °C, 14 times that of Ti3C2.