Phase Quantification of Heterogeneous Surfaces Using DFT-Simulated Valence Band Photoemission Spectra

Abstract

Quantifying the crystallographic phases present at a surface is an important challenge in fields such as functional materials and surface science. X-ray photoelectron spectroscopy (XPS) is routinely employed in surface characterization to identify and quantify chemical species through core line analysis. Valence band (VB) spectra contain characteristic but complex features that provide information on the electronic density of states (DoS) and thus can be understood theoretically using density functional theory (DFT). Here, we present a method of fitting experimental photoemission spectra with DFT models for quantitative analysis of heterogeneous systems, specifically mapping the anatase to rutile ratio across the surface of mixed-phase TiO 2 thin films. The results were correlated with mapped photocatalytic activity measured using a resazurin-based smart ink. This method allows large-scale functional and surface composition mapping in heterogeneous systems and demonstrates the unique insights gained from DFT-simulated spectra on the electronic structure origins of complex VB spectral features.

Synthesis of CaC2 and the Adsorption Mechanism of Alkaline Metals on the CaC2 Surface

“…With the development of quantum theory and advances in quantum chemical computational methods, semiempirical or self-invented methods can provide systematic and reliable explanations and predictions to practice by investigating the structure, physical properties, reaction mechanisms, and reactivity . Materials Studio (MS) qualitatively analyzes the adsorption behavior of the most important minerals in coal/coal ash and provides information on their reactivity.…”