Machine learning approach for elucidating and predicting the role of synthesis parameters on the shape and size of TiO2 nanoparticles

Abstract

In the present work a series of design rules are developed in order to tune the morphology of TiO2 nanoparticles through hydrothermal process. Through a careful experimental design, the influence of relevant process parameters on the synthesis outcome are studied, reaching to the develop predictive models by using Machine Learning methods. The models, after the validation and training, are able to predict with high accuracy the synthesis outcome in terms of nanoparticle size, polydispersity and aspect ratio. Furthermore, they are implemented by reverse engineering approach to do the inverse process, i.e. obtain the optimal synthesis parameters given a specific product characteristic. For the first time, it is presented a synthesis method that allows continuous and precise control of NPs morphology with the possibility to tune the aspect ratio over a large range from 1.4 (perfect truncated bipyramids) to 6 (elongated nanoparticles) and the length from 20 to 140 nm.

AFM Measurements and Tip Characterization of Nanoparticles with Different Shapes

“…Complex geometry NPs are fabricated by Università degli Studi di Torino by tuning the hydrothermal synthesis parameters [14,19], and obtaining TiO 2 anatase NPs with two different shapes (bipyramids and nanosheets), which are mostly used for their photocatalytic properties. Samples for AFM imaging are made by depositing a drop of a 3 mg L −1 suspension of NPs onto a freshly cleaved mica support.…”

Customizing New Titanium Dioxide Nanoparticles with Controlled Particle Size and Shape Distribution: A Feasibility Study Toward Reference Materials for Quality Assurance of Nonspherical Nanoparticle Characterization

“…Recently, the reproducible preparation of anatase bipyramids with high percentage of {101} exposed was achieved by the hydrothermal treatment of Ti(IV)-triethanolammine complex aqueous solution at 423À483 K. [52,53] Variation of the temperature allows the control of particle size. At 453 K, uniform bipyramids with 20 nm hydrodynamic radius are obtained.…”

“…The synthesis of the bipyramidal nanoparticles considered in this work (see Figure 1b) has been carried out with this last method, as described in several papers. [45,53,54] Figure 3. TiO 2 layers a) as coating synthesized by pulsed DC magnetron sputtering (after scratching it with a scalpel) and b) screen printed with the bipyramidal nanoparticles from Figure 1c as the starting material.…”

“…They found that high pH values and low temperatures are able to favor the growth of the nanoparticles along the c ‐axis, resulting in high‐aspect‐ratio nanoparticles. The acicular nanoparticles taken into consideration in this manuscript (Figure 1c) were synthesized with the same method described by Pellegrino et al [ 53 ] The presence of high‐energy facets in these kinds of nanoparticles is very low; see the high‐resolution image in Figure . They mainly expose {101} surfaces grown on on each other in very short sequences, so that the final shape becomes elongated/acicular, not having a well‐defined simple shape like rod or bipyramid.…”

Controlled Periodic Illumination Enhances Hydrogen Production by over 50% on Pt/TiO2

“…The photocatalytic experiments were carried out on bipyramidal TiO 2 nanoparticles synthesized through a hydrothermal method (see Supporting Information (SI) Figure S1 ). 26 The Pt nanoparticles were deposited through photoreduction under UV irradiation using formic acid as a hole scavenger (see SI Figure S2 ). The deposition time of the Pt onto the TiO 2 bipyramids was fixed to 5 min under 20 W m –2 of continuous irradiation (details in SI ).…”