J Nanostruct 9(1): 172-182, Winter 2019 RESEARCH PAPER Hydrothermal Synthesis, Characterization and Catalytic Performance of La 3+ and Sm 3+ - Doped Bi 2 Mn 2 O 7 Nanocatalysts for Biginelli Reactions Shahin Khademinia and Mahdi Behzad* Department of chemistry, Semnan University, Semnan, Iran * Corresponding Author Email: mbehzad@semnan.ac.ir ARTICLE INFO Article History: Received 08 October 2018 Accepted 14 November 2018 Published 01 January 2019 Keywords: Biginelli Hydrothermal Lanthanum; Nanocatalysts; Pyrochlores Samarium ABSTRACT How to cite this article Khademinia S, Behzad M. Hydrothermal Synthesis, Characterization and Catalytic Performance of La 3+ and Sm 3+ - Doped Bi 2 Mn 2 O 7 Nanocatalysts for Biginelli Reactions. J Nanostruct, 2019; 9(1):172-182. DOI: 10.22052/JNS.2019.01.019 La 3+ and Sm 3+ - doped Bi 2 Mn 2 O 7 nanocatalysts were synthesized in 1 M NaOH aqueous solution, via a stoichiometric 1:1 Bi:Mn molar ratio hydrothermal method at 180 °C for 48 h. Bi(NO 3 ) 3 , MnO 2 , La(NO 3 ) 3 and Sm 2 O 3 were used as raw materials. Te synthesized nanomaterials were characterized by powder X-ray difraction (PXRD) technique. Both of the La 3+ and Sm 3+ - doped Bi 2 Mn 2 O 7 nanomaterials were crystallized in a cubic crystal structure with space group . Te morphologies of the synthesized materials were studied by field emission scanning electron microscope (FESEM). Te optical properties of the as-synthesized nanomaterials were studied by ultraviolet visible (UV-Vis) difuse refectance spectra (DRS). It was found that the optical band gaps were increased with dopoing La 3+ and Sm 3+ into Bi 2 Mn 2 O 7 . Catalytic performance of the synthesized nanomaterials were investigated in Biginelli reactions which showed excellent eficiency. Correlation between the catalytic performance with the band gap and hard/sof proportion of the metal ions was shown. INTRODUCTION A 2 B 2 O 7 pyrochlore type materials (where A is a medium-large caton and B is an octahedrally coordinated, high-charge caton) with space group of can be described as a fuorite superstructure with O anions ordered around the A and B catons. These materials have been widely studied as ferroelectric and/or magnetc materials, ionic conductors, catalysts and radiaton resistant materials [1-6]. Pyrochlore materials have atracted great interest due to their ability to form substtuted and defectve structures, permitng interestng physical propertes [7-9]. Rare earth (RE) compounds have been extensively studied as potental laser host materials, oxygen ion conductors, and fuorescent lamp phosphors due to their atractve optcal, electric, and magnetc propertes, which are atributed to the electronic transitons of rare earth ions between the 4f energy levels [10–13]. In the RE family, Sm 3+ is one of the most important actve ions and can show intense line-like absorpton bands for special infrared light because of its closely lying energy level structure [14]. In recent years, considerable eforts have been focused on the fabricaton of ceramic materials and RE oxides [12–20]. Doping is expected to introduce defect and change in the latce energy of the crystals. La 2 O 3 has also the greatest efect among the various additves in changing the latce energy of crystals [21]. The Biginelli reacton was originally reported by Biginelli in 1891 [23]. It is a methodology for the synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatves (DHPMs) in a one-step procedure. DHPMs have shown several applicatons [24]. Several metal oxides have been reported as Tis work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.