Reading at exposed surfaces: theoretical insights into photocatalytic activity of ZnWO4

Abstract

Understanding the criteria warranting the existence, stability, and activity of a given configuration of atoms has pivotal relevance in chemical and materials science. Photocatalysts, traditionally semiconductors, are essential for processes ranging from water purification to water splitting, air filtration, and surgical instrument sterilization, and harvest optical energy to drive chemical reactions. These semiconductors harvest optical energy to drive chemical reactions. With chemical reactions dictated by atomic and molecular interactions at the nanoscale, examining these processes with near-atomic resolution is necessary to understand photochemical processes in depth and to improve materials for next-generation catalysts. The performance and key electronic properties of semiconductors are dictated by the interplay between the surface chemistry and morphology, whose manipulation has inspired experimental and theoretical researchers. This interplay has been clarified by theoretical studies based on atomic-scale modelling with particular attention given to two sets of degreesof-freedom: the atomic positions and chemical configuration. This perspective article presents the major computational challenges and modern methodological strategies toward advancing the field. The ZnWO 4 material was selected as a case study, and the key concepts developed in recent years are discussed to clarify the morphology, i.e., the exposed surfaces of materials, and explain its functional properties or performance. First-principle calculations capture the geometric and electronic effects on the photocatalytic activity in agreement with experimental data. Indeed, important and often surprising structure-function relations have been observed based in depth atomistic modelling on morphological analysis. An overview of past achievements and future directions is provided according to the authors' outlook.

The stability and electronic and photocatalytic properties of the ZnWO4 (010) surface determined from first-principles and thermodynamic calculations

“…9,10,15,16 For understanding and predicting the photocatalytic activity of ZnWO 4 , knowledge of the atomic structure and properties of surfaces is essential. 17,18 The (010) surface of ZnWO 4 has received extensive attention over the past few years because of its suitable cleavage property. Theoretically, Opoku et al nd that the surface energy of the (010) surface is smaller than that of the (100) and (001) surfaces, indicating that the (010) surface is more stable than the (100) and (001) surfaces.…”

“… 9,10,15,16 For understanding and predicting the photocatalytic activity of ZnWO 4 , knowledge of the atomic structure and properties of surfaces is essential. 17,18 …”

Selective Synthesis of α-, β-, and γ-Ag2WO4 Polymorphs: Promising Platforms for Photocatalytic and Antibacterial Materials

“…By combining simulations based on first-principles calculations at the DFT level with experimental studies, our research group has recently proven that this strategy is a valuable design aid to achieving an optimum morphology since it offers a high-fidelity approach that results in the rapid in silico prediction of crystal growth habits. In addition, it allows us to establish a correlation among the morphology, properties, and subsequent applications for both micro- and nanomaterials, such as ZnO, Ag 2 O, Ag 3 PO 4 , , α-Ag 2 WO 4 , , PbMoO 4 , BaWO 4 , and ZnWO 4 . , A proof of concept has been developed that demonstrates the automation feasibility of the models − used to obtain the set of morphologies available and match the theoretical morphology with the images displayed by FE-SEM. This proof of concept also motivates their continued development.…”

The role of counter-ions in crystal morphology, surface structure and photocatalytic activity of ZnO crystals grown onto a substrate

“…The Wulff theorem provides a simple relationship between the surface energy (E surf ) of a plane and its respective distance from the center of the particle [61]. The strategy of modulating the surface energies to describe the morphology changes observed in experimental data has been successful performed by our group [60,65,66]. This procedure is considered a powerful tool for understanding the superficial stabilizations caused by the modification in some synthesis parameters.…”