A new and simple method of biosynthesis assisted by tannic acid (C 76 H 52 O 46 ) is used to obtain bismuth trioxide nanoparticles Bi 2 O 3 in which the b-Bi 2 O 3 phase is identified. Synthesis takes place at room temperature and atmospheric pressure from the reduction of bismuth nitrate pentahydrate (Bi(NO 3 ) 3 Á5H 2 O) in solution, using tannic acid as a reducing agent and stabilizer. Nanoparticles with an average size of 10.99 ± 0.27 nm are obtained, and the structural properties of the nanoparticles are observed using transmission electron microscopy techniques, as well as UV-Visible-NIR spectroscopy, with which a semiconductor behavior with band gap within a range of (2.57-3.02) eV is observed. Using Raman spectroscopy, it is possible to observe and identify different normal modes of vibration, characteristic of the b-Bi 2 O 3 phase.

This paper introduces a methodology of characterization of nanostructured systems in which transmission electron microscopy is used as a central element of the study. Experimental studies of HREM are performed in parallel with studies in the Simula TEM program to stimulate high-resolution images and diffraction patterns. To confirm the accuracy of the results, studies of X-ray diffraction (XRD) were performed. In order to illustrate the methodology, bismuth oxide Bi2O3 nanoparticles are synthesized by a method of biosynthesis because this sample is rich in structural information.