Nanoclay-modulated oxygen vacancies of metal oxide

Abstract

The formation of oxygen vacancies is one of the most critical factors that can improve the electronic and catalytic properties of metal oxides, in which an important challenge is to lower the formation energy of oxygen vacancies at the interface structure. Here we show that clay surfaces rich with hydroxyl groups can induce the formation of oxygen vacancies in metal oxide catalysts. Based on density functional theory calculations, kaolinite is shown to hinder the surface dehydration process of Co 3 O 4 nanoparticles, and enhances the charge transfer process at the interface by the highly diffusible protons. Experimental results confirm that vacancy-rich Co 3 O 4 is easily produced by a reduction method and kaolinite enhances the formation of oxygen vacancies and divalent cobalt on the nanoparticle surface. As expected, the defective Co 3 O 4 /kaolinite exhibits enhanced catalytic and electrocatalytic performances. This finding provides an improved way to design efficient clay-based catalysts.

Optimized Synthesis Routes of MnOx-ZrO2 Hybrid Catalysts for Improved Toluene Combustion

“…For example, manganese-based oxides have been confirmed as one of the most potential alternates to noble metal catalysts and exhibited high catalytic activity due to the high mobility of lattice oxygen and the existence of transformation of unstable valence states, such as Mn 4+ ↔ Mn 3+ ↔ Mn 2+ [12][13][14][15]. In addition, the physical and chemical characteristics of the catalysts, such as morphology [8,16], specific surface area [17], oxygen vacancy [18], reducibility, and reactivity of lattice oxygen [19], oxygen migration rate [14], also determine the efficiency of the catalytic oxidation of VOCs. However, it is difficult to efficiently remove certain VOCs for a single phase of MnO x due to the poor thermal stability [12,20].…”

Evaluation of Qusaiba Kaolinitic Shale as a Supplementary Cementitious Material in Lightweight Oil-Well Cement Formulation

“…Weight loss from the initial temperature to 230 °F is attributed to the escape of adsorbed water. 31 Additionally, loss in weight as a result of dehydroxylation occurs within 959 to 1634 °F. 7 , 32 All heated samples show slight weight loss; however, the least weight loss occurs in the sample heated at 1526 °F, indicating a higher degree of dehydroxylation.…”

Origin of the Photoluminescence of Metal Nanoclusters: From Metal-Centered Emission to Ligand-Centered Emission

“…Most importantly, with respect to the paramount importance and universality of ligand and interface interaction at the nanoscale interface, the proof of concept of PBIS not only elucidates the fundamental physical principles driving nanoscale PL emission phenomena, but it also provides completely new insights to understand the interface-confined nanocatalysis on the molecule level. The presence of a new interface state with a low energy level could act as an extra channel to promote election transfer, which reduces the energy barrier of redox reaction, similar to the role of the transition state called in the heterogeneous catalysis [112,113]. At the same time, if the atomic orbitals of reactants interact with the PBIS, the binding strength of the reactant with the metal active site could be optimized (the classical Sabatier principle), which will improve the selectivity and lifetime of catalysts [114].…”