Enhance the photocatalytic performance of TiO2 nano-semiconductor by simultaneously doping of transition and lanthanide elements for the CC homocoupling reaction under sunlight irradiation

Designing a highly powerful catalytic system for CC bond formation reactions is very challenging in synthetic organic chemistry. Herein, we report twelve new nanoparticles which were synthesized. These nanoparticles included 2-nuclear (transition metal-doped) and 3-nuclear (lanthanide–transition metals) doped titanium oxides with high surface activities and low energy bandgaps. All the obtained nanoparticles were characterized by X-ray diffraction, Brunauer–Emmett–Teller, Langmuir analysis, the Barrett–Joyner–Halenda​ method, field-emission scanning electron microscopy, inductively coupled plasma mass spectrometry, Fourier-transform infrared, diffuse reflection/transmittance spectroscopy and UV–Vis spectroscopy. The roles of the surface activity and energy bandgap of these nanoparticles were tested through a photocatalytic test by considering the synthesis of bibenzyl via dehalogenative CC homocoupling using benzyl chloride as the precursor under sunlight for the first time. Based on the results, upon adding lanthanide as an extra dopant, the surface activity of the nanoparticles was remarkably incremented, while the energy bandgap did not show an observable change after lanthanide doping. According to the results, the efficiency of bibenzyl production was higher in the presence of TixMyLamOz as compared to TixMyOz, with a conversion of 85% for TixCuyLamOz compared to 80% for TixCuyOz, as the most effective catalysts in their categories. Although both types were able to absorb light in the visible and IR regions, the surface activity played a critical role and made TixMyLamOz a more useful photocatalyst in CC homocoupling reactions. Noteworthy, the next step of this experiment is to test these photocatalysts for a series of CC coupled derivatives. © 2022 Elsevier B.V.