3 research outputs found
A 2D Graph-Based Generative Approach For Exploring Transition States Using Diffusion Model
The exploration of transition state (TS) geometries is crucial for
elucidating chemical reaction mechanisms and modeling their kinetics. In recent
years, machine learning (ML) models have shown remarkable performance in TS
geometry prediction. However, they require 3D geometries of reactants and
products that can be challenging to determine. To tackle this, we introduce
TSDiff, a novel ML model based on the stochastic diffusion method, which
generates the 3D geometry of the TS from a 2D graph composed of molecular
connectivity. Despite of this simple input, TSDiff generated TS geometries with
high accuracy, outperforming existing ML models that utilize geometric
information. Moreover, the generative model approach enabled the sampling of
various valid TS conformations, even though only a single conformation for each
reaction was used in training. Consequently, TSDiff also found more favorable
reaction pathways with lower barrier heights than those in the reference
database. We anticipate that this approach will be useful for exploring complex
reactions that require the consideration of multiple TS conformations
Perovskite Nano-Powder and Nano-Film Catalysts in Mineralization of Aqueous Organic Contaminants through Solar Simulated Radiation
Water contamination with various contaminants, including organic species, is a global concern. Reclamation through safe, economic and technically feasible methods is imperative. Two perovskites, zinc titanate (ZnTiO3) and manganese titanate (MnTiO3), mixed with TiO2 phases, were prepared as nano-powders and nano-films. The materials were characterized and used as catalysts in photodegradation of aqueous methylene blue, a hazardous model contaminant, using solar simulated radiation. The effects of various reaction conditions on the photodegradation were examined. The kinetics indicated the suitability of using the process at various contaminant concentrations and catalyst loadings. Both powder and film catalysts completely removed the contaminant in less than 6 h. Powder and film forms of the MnTiO3 mixture were more efficient than their ZnTiO3 counterparts. In both perovskite mixtures, the films exhibited higher catalytic efficiency than the powders. The film materials exhibited high catalytic efficiency in both the continuous flow and batch processes. Water contaminated with various methylene blue concentrations can be treated by the film catalysts that can be recovered and reused with no technical difficulties. The results open new horizons for larger-scale water purification processes