Nanophase-Prepared Undoped Magnetic Stannic Dioxide Semiconductor for Space Applications

Nanophase materials have emerged instrumental in space science applications. Among them, stannic dioxide nanoparticles are especially focused due to their wide band gap, large surface-to-volume ratio, gas sensing, high chemical stability, thermal absorptivity, energy and photocatalytic actions. In spacecrafts, it serves in atmosphere monitoring and purification of air and water, and biosensor of gas like methane and coupled to cryogenic or volcanic plume analyzers on moons. Here we report ecofriendly synthesis of nanophase stannic dioxide and its features based on x-ray diffraction, WH plot, and zeta potential (stability) measurements. Unit cells are found tetragonal with lattice parameters a and b, equal to 4.75 Å each, and c=3.22 Å. Williamson-Hall plot gives a particle size of 3.13 nm with a positive micro-strain of 0.012. Stability and agglomeration suggested by the observed values of zeta potentials are consistent with SEM image. It exhibits blue shifted band gap of 4.39 eV, measured from Tauc's plot in uv-visible range, suitable for photocatalysis and energy applications in space. Using VSM measurement, hysteresis was observed in M-H plane which indicated to ferromagnetism in pure SnO2 without any magnetic element doping, possibly attributable to defect states.