This review emphasizes La-based metal oxides of the perovskite form and their application in heterogeneous catalytic transfer hydrogenation (CTH) reactions from year 2013. Perovskites are potential alternatives to noble metals. The possibility of induced-synergy between two cations in the ABO₃ or multicationic perovskites makes them attractive for hydrogenation reactions. Herein, we look at recent developments in their synthesis protocols, and how the various physicochemical properties derived from the individual synthesis protocols affect the catalytic performances of perovskite oxides in transfer hydrogenation reactions. Furthermore, we review different type of perovskite-based catalysts and the mechanisms of the surface catalyzed transfer hydrogenation reactions.

This study describes for the first time the synthesis, characterization, and application of a MnFe2O3/GO core–shell nanocomposite as an adsorbent for the removal of levofloxacin (Lev) from real water samples. The formation of the proposed nanocomposite was confirmed using various characterization techniques. The structural techniques revealed a 20 nm average particle size of the MnFe2O3/GO core–shell nanocomposite, with a surface area of 70.7 m2 g–1, as shown by the BET results. The most influential parameters (adsorbent dosage, stirring rate, and Lev pH) that affected the adsorption process were optimized using the response surface methodology (RSM) based on a central composite design. The optimum conditions were 0.007 g, 2, and 7 for adsorbent dosage, stirring rate, and Lev pH, respectively. The adsorption behavior of Lev on the MnFe2O3/GO core–shell nanocomposite was examined using isotherm models, kinetics, and thermodynamics. The kinetic models demonstrated that the adsorption process was controlled by both intraparticle and outer diffusion. Furthermore, the results obtained revealed that the adsorption of Lev on MnFe2O3/GO was dominated by electrostatic interactions. Moreover, Dubinin-Radushkevich and Temkin isotherms confirmed that the sorption mechanism was dominated by electrostatic interactions, while Langmuir and Sips models confirmed a monolayer adsorption process. The maximum adsorption capacity of Lev onto the MnFe2O3/GO adsorbent was found to be 129.9 mg g–1. Furthermore, the thermodynamic data revealed that the adsorption system was spontaneous and exothermic. The synthesized MnFe2O3/GO core–shell nanocomposite showed significant recyclability and regenerability properties up to five adsorption–desorption cycles. As a proof of concept, the performance of the prepared adsorbent was evaluated for laboratory-scale purification of spiked real water samples. The prepared adsorbent significantly reduced the concentration of Lev in the real water samples and the removal efficiency ranged from 86 to 97%.

Lanthanum-based perovskites, LaMO₃ (M = Co, Fe, Mn, Ni, Cr, Cu, Zn) were synthesized using sol–gel method and characterised using both physical and chemical techniques.

Aldol condensation is arguably one of the most fascinating reactions that leads to the formation of C–C bonds. Its use in the pharmaceutical industry to synthesis complex drugs from simple aldehydes and ketones has become of paramount importance. Although this is one reaction that has lured a lot of attention, not enough has been explored in heterogeneous catalysis. In this work we have successfully synthesized multicationic perovskites via the soft-template method and characterized them thoroughly. The synthesized perovskite nanocrystals were found to have small S_BET however their catalytic application in the conversion of benzaldehyde (BAL) in the aldol condensation with diethyl ketone (DEK) was found to be astonishing. The synthesis was confirmed using many techniques, from determining the oxidation states of the materials using XPS. This gave access to determine the coordination of the metals in the perovskite lattice and also qualitatively assess the oxygen environments that exist. The oxygen vacancies and S_BET were used to assess the activity of the perovskite catalysts in the cross-aldol condensation reaction. The optimal conditions for this aldol condensation were found to be 120 °C after 25 h with no solvent using SrMo_0.5Ni_0.5O_3-δ inorganic perovskite which had the highest amount of oxygen vacant sites which gave a conversion of 88 % and an 82 % selectivity towards the desired cross-aldol condensation product. The use of dimethylformamide (DMF) for this reaction is discouraged as it reacts with BAL to produce a higher amide.