NiZr/N-doped TiO2/Ti3C2 catalyst for the selective hydrogenation of cinnamaldehyde: effect of N-doping of TiO2

Graphical Preparation of NiZr/N-doped TiO 2 /Ti 3 C 2 catalyst for catalytic cinnamaldehyde (CAL) hydrogenation by KBH 4 reduction. N-doped TiO 2 on Ti 3 C 2 , and N-doping substituted O in the TiO 2 lattice to create oxygen vacancies on the surface, increase the surface acidity, and adsorb C=O bonds, which resulted in high cinnamaldehyde conversion and cinnamyl alcohol (COL) selectivity after reaction 8 h. An NiZr/N-doped TiO 2 /Ti 3 C 2 catalyst was prepared by KBH 4 reduction for cinnamaldehyde hydrogenation. Characterization results showed that the synthesis of N-doped TiO 2 on Ti 3 C 2 and the uniform dispersion of TiO 2 on the Ti 3 C 2 surface increased the specific surface area of NiZr/Ti 3 C 2 by 164.4 m 2 /g. N-doping at a level of 19.03 % was used to replace O in the TiO 2 lattice; the Ti−O−Ti peak in the XPS spectrum of the undoped catalyst was shifted by 0.3 eV in the spectrum of the doped catalyst; as a result, there was a 15.40 % increase in the number of surface oxygen vacancies of the NiZr/Ti 3 C 2 catalyst. The synthesis of N-doped TiO 2 on Ti 3 C 2 converted the moderately acidic sites of NiZr/Ti 3 C 2 to strong Lewis acid sites and increased the total number of acid sites by approximately 0.8-fold. The active Lewis acid sites on the surface of NiZr/N-doped TiO 2 /Ti 3 C 2 adsorbed only C=O bonds and inhibited the adsorption of C=C bonds, resulting in a high cinnamaldehyde conversion of 90.69 % and a cinnamyl alcohol selectivity of 91.87 %.