Challenges in the theoretical description of nanoparticle reactivity: Nano zero‐valent iron

Abstract

The reactivity of iron atoms, clusters, and nanoparticles (nZVI) is of increasing interest owing to their important practical applications, ranging from the steel industry to water remediation technologies. Here, we provide an overview of computational methods and models that can be applied to study nanoscale zero‐valent iron (nZVI) reactions and discuss their benefits and limitations. We also report current progress in calculations through recent examples treating the reactivity of nZVI particles. Finally, we consider the potential use of highly accurate methods with favorable scaling (such as quantum Monte Carlo or random phase approximation), which are currently considered too computationally expensive but are expected to become more amenable in the future as computer power increases. © 2014 The Authors International Journal of Quantum Chemistry Published by Wiley Periodicals, Inc.

Anaerobic Reaction of Nanoscale Zerovalent Iron with Water: Mechanism and Kinetics

“…Both activation barriers (ΔG ⧧,atom = 31.6 kcal/mol for an iron atom, ΔG ⧧,surf = 18.0 kcal/mol for an infinite periodic surface) may be considered as (upper/lower) limits for the real reaction barriers observed for nZVI; nZVI itself contains too large a number of atoms for modeling. General agreement of ΔG ⧧ with the measurement and the order ΔG ⧧,atom > ΔG ⧧,nZVI > ΔG ⧧,surf consistent with preliminary data on small iron clusters 26 confirmed the suggested reaction mechanism. Such a joint experimental and theoretical study provided data on the reactivity of nZVI which may also help to identify shortcomings of current methods and models; hence, theoretical description of nZVI and its reactivity is still challenging.…”

“…Such a joint experimental and theoretical study provided data on the reactivity of nZVI which may also help to identify shortcomings of current methods and models; hence, theoretical description of nZVI and its reactivity is still challenging. 26…”

“…As such, it is preferable to model the nZVI particle either as a cluster of a few iron atoms or as a solid-phase surface. 26 Unfortunately, both approaches suffer from drawbacks and limitations; in particular, the sizes of systems involved, the need for periodic boundary conditions, and simulation of electron correlation mean that the use of density functional theory (DFT) methods is required. This is a potentially serious issue because DFT functionals do not always provide systematic results for transition-metal (TM) compounds, and the accuracy of their results is highly system dependent.…”

Nanocrystalline iron–boron catalysts for low-temperature CO hydrogenation: Selective liquid fuel production and structure–activity correlation

“…The diffusion of carbon requires a molecular dynamics simulation of thousands of trajectories with properly chosen potential energy surface. Simulating this complicated phase transformation process is challenging for quantum chemistry for the time being [50].…”

Síntese E Caracterização De Nanopartículas De Ferro De Valência Zero

“…As nanopartículas de ferro de valência zero (FVZ) são de grande interesse, para setores, como por exemplo, desde a indústria do aço ao tratamento de água e efluentes [2][3][4] e remediação de solos contaminados. Estas partículas vêm sendo utilizadas em barreiras reativas permeáveis, capaz de degradar contaminantes existentes em uma pluma contaminada in loco, através de processos físicos, químicos e biológicos [2][3][4][5]. A síntese de nanopartículas de FVZ pode ser obtida por diferentes metodologias [6], tais como, via hidrogenação [7], decomposição térmica [8], via oxidação do hidrogênio gasoso [9] e via reação com borohidreto de sódio [10][11][12][13][14][15][16][17].…”