Defect-induced optical and electrochemical properties of Pr 2 Sn 2 O 7 nanoparticles enhanced by Bi 3+ doping
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Defect-induced optical and electrochemical properties of Pr2Sn2O7 nanoparticles enhanced by Bi31 doping Allen Abraham1, Santosh K. Gupta2, Swati Mohan1, Hisham Abdou1, Yuanbing Mao3,a) 1
Department of Chemistry, University of Texas Rio Grande Valley, Edinburg, Texas 78539, USA Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai-400085, India 3 Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616, USA a) Address all correspondence to this author. e-mail: [email protected] 2
Received: 13 November 2019; accepted: 10 February 2020
Materials that show superior light-emitting and catalytic properties are in high demand among the scientific community owing to their applications in the areas of optoelectronics and (opto)electrocatalysis. In this work, we have synthesized sub-10-nm Pr2Sn2O7 (PSO) and Pr2Sn2O7:Bi3+ (PSOB) nanoparticles (NPs) and investigated their optical and electrochemical properties. On ultraviolet irradiation, PSO NPs display blue emission because of the presence of oxygen vacancies. Interestingly, PSOB NPs have higher blue emission intensity than undoped PSO NPs owing to the increase in oxygen vacancy defect density induced by Bi3+ doping. Moreover, PSOB NPs display higher efficiency in terms of current density than PSO NPs as a catalyst toward the oxygen evolution reaction (OER). The kinetic OER models of PSO and PSOB NPs are quite different as displayed by their different Tafel slopes. Interestingly and as another advantage, the PSOB sample is more conducting with low impedance value than the PSO counterpart. With all these advantages due to high oxygen vacancies induced by Bi3+ doping, PSOB NPs have a great potential to be used as blue phosphors, charge storage devices, and capacitors.
Introduction Defects are not always deleterious. They sometimes lead to various interesting optical, magnetic, catalytic, electrochemical, and conducting properties [1, 2, 3, 4, 5, 6, 7]. For example, vacancies could not only act as the scattering centers of charge carriers to limit the transport properties but also as reaction centers to improve the adsorption, nucleation, and assembly of molecules on the surface [8]. A2B2O7-type pyrochlore materials have received significant attention among the materials science research community for a range of applications because of their unique properties. These properties encompass low thermal conductivity, high dielectric constant, large band gap, high radiation stability, order–disorder phase transition, excellent structural stability, etc. [9, 10, 11, 12, 13]. These applications include nuclear waste hosts [12], luminescence hosts [14], X-ray scintillators [15], catalysts [16], magnetic materials [17], and sensors [18]. The A2B2O7 pyrochlore structure belongs to the Fd 3m space group and is related to the fluorite one. One-eighth of the pyrochlore unit cell differs from the fluorite unit cell because it has two different cations and an anion vacancy [19].
ª Materials Research Society 2020
It is reported that these kind of pyrochlore oxi
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