Ultrathin Znti-Ldh Nanosheet: A Bifunctional Lewis and Bronsted Acid Photocatalyst for Synthesis of N-Benzylideneanilline Via a Tandem Reaction

Ultrathin ZnTi-LDH nanosheet with the thickness of 1.4 nm was prepared to study the interplay between active site and catalytic performance in photocatalytic synthesis of N-benzylideneanilline via a tandem reaction. Experimental results and DFT calculations jointly revealed that ZnTi-LDH nanosheet possesses dual isolated active sites including unsaturated Ti atoms (Lewis acid) and H atoms of OH groups (Brønsted acid), achieving the activation of benzyl alcohol and nitrobenzene via C-O … Ti and N-O … H-O, respectively. Photogenerated holes and electrons facilitate the oxidation of benzyl alcohol to benzaldehyde and the reduction of nitrobenzene to aniline, respectively. By reducing ZnTi-LDH nanosheet thickness, more active sites would be exposed, facilitating not only the activation of reactants but also the separation of photogenerated carriers. Therefore, a thinner ZnTi-LDH nanosheet shows the high conversion (100%) and the high selectivity (96%). Finally, a synergetic photocatalytic mechanism associated with the molecular activation was proposed at the molecule level.