Tuning the Catalytic Activity of NiO via Neodymium Doping for Selective Benzaldehyde Formation

Microwave-assisted method is used to synthesis Nd doped NiO and characterized by XRD, FTIR, SEM, TEM, BET, UV-Vis DRS, and PL analyses. XRD results confirmed the single-phase cubic structure of NiO, and the incorporation of Nd³⁺ ions into the Ni²⁺ lattice sites was clear from the peak shifts and decrease in crystallite size from 24.5 nm to 17.6 nm. The FTIR spectra revealed metal–oxygen vibrations (Ni–O, Nd–O–Ni) in the 450–900 cm⁻¹ region, while SEM and TEM images showed irregular nanoparticles with slight agglomeration at higher dopant concentrations. The optical band gap narrowed from 3.38 eV (pure NiO) to 2.15 eV (0.05 mol% Nd:NiO), indicating enhanced electronic transitions. BET analysis showed an increase in surface area from 41.31 to 55.23 m²/g upon Nd dopingUsing tert-butyl hydroperoxide (TBHP) as an oxidant, the samples' catalytic activity was examined for the conversion of styrene to benzaldehyde. The 0.04 mol% Nd:NiO catalyst exhibited maximum benzaldehyde selectivity (87.8%) and yield (46.9%) at 70°C with acetonitrile as the solvent. Recyclability tests confirmed the stability and reusability of the catalyst for multiple cycles.