Birnessite-Type Manganese Dioxide Nanosheets on Metal–Organic Frameworks with High Catalytic Activity in Ozone Decomposition

Abstract

Ground-level ozone (O 3 ) poses a threat to both human health and ecosystems; the development of O 3 decomposition catalysts is thus of fundamental and practical significance. In the past decades, metal oxides have been widely investigated for O 3 elimination due to their low cost and high catalytic activity. Recently, it has been demonstrated that metal−organic frameworks (MOFs) could also show high performance in the removal of O 3 and even other airborne gaseous pollutants at the same time. Herein, we report a facile synthetic method to prepare the composite of the well-known MOF, UiO-66-NH 2 , and birnessitetype manganese dioxide, namely, δ-MnO 2 , where the nanosheets of δ-MnO 2 are vertically aligned and densely grown on the crystal surfaces of UiO-66-NH 2 . The δ-MnO 2 /UiO-66-NH 2 composite could completely remove low-concentration O 3 (5 ppm) in both dry and highly humid (RH = 80%) air at ambient temperature and pressure with a space velocity of 2000 L h −1 g −1 . In contrast, a single-phase sample of δ-MnO 2 or the typical O 3 decomposition catalyst, α-MnO 2 , showed a much lower O 3 removal efficiency under the same experimental conditions. Due to the ultrathin morphology (high surface area) and well-separated distribution (no aggregation) of δ-MnO 2 nanosheets in the δ-MnO 2 /UiO-66-NH 2 composite, there are rich Mn 2+ /Mn 3+ atoms and oxygen vacancies on its surface, contributing to its high performance in catalytic O 3 decomposition. This work demonstrated a facile method to prepare MOF-based composites with fascinating nanostructures and high catalytic activity in O 3 decomposition, which are also potentially useful in other catalytic reactions.

MOF-based catalysts: insights into the chemical transformation of greenhouse and toxic gases

“…The composite shows highlight O 3 removal in the low-concentration range (5 ppm) under both dry and relative humidity (80%) at ambient temperature and pressure, with a space velocity of 2000 L h −1 g −1 . 169…”

Nanoporous {Pb3}-Organic Framework for Catalytic Cycloaddition of CO2 with Epoxides and Knoevenagel Condensation

“…Metal–organic frameworks (MOFs), as a type of material with unique functions, have attracted great interest and notice in recent years because of their distinctive confined microspatial structural features and promising applications in gas separation and storage, heterogeneous catalysis, fluorescent recognition reagents, drug delivery systems, etc. − because their diversity and modularity can provide opportunities for systematic fine-tuning and control of targeted properties and/or performance. Usually, one or two commercially available linear or curved polybasic organic carboxylic acids are used as ligands to coordinate with metal ions in the periodic table under various transformation conditions, ultimately obtaining three-dimensional (3D) porous host frameworks.…”

Recent Advances in Laser‐Induced Synthesis of MOF Derivatives

“…The ultrahigh surface area, structural tunability, and diversity of their crystalline nature allow the MOFs to be perfect carrier materials and can be easily converted into MOF derivatives by pyrolysis (Figure 1). [8][9][10][11][12][13] MOF derivatives are commonly used as functional materials in catalysis, clean energy, biomedicine, and environmental remediation applications. [13][14][15][16] Up to now, various approaches have been employed for the pyrolysis of MOFs to MOF derivatives.…”