Confined Transformation of Organometal‐Encapsulated MOFs into Spinel CoFe₂O₄/C Nanocubes for Low‐Temperature Catalytic Oxidation

Abstract

Development of spinel bimetallic oxides as low‐cost and high‐efficiency catalysts for catalytic oxidation is highly desired. However, rational design of spinel oxides with controlled structure and components still remains a challenge. A general route for large‐scale preparation of spinel CoFe2O4/C nanocubes transformed from organometal‐encapsulated metal–organic frameworks (MOFs) via exchange–coordination and pyrolysis combined method is reported. Strong confinement effect between organometallics and MOFs realizes reconstruction of crystal phase and composition, but not simple metallic oxides support by Co2+ introduction. Compared with Co3O4‐Fe2O3/C, MOFs‐derived cubic nano‐CoFe2O4/C with higher surface area (115.7 m2 g−1) and favorable surface chemistry exhibits excellent catalytic activity (100% CO conversion at 105 °C) and competitive water‐resisting stability (total conversion at 145 °C for 20 h). Turnover frequency of CoFe2O4/C reaches 4.26 × 10−4 s−1 at 90 °C, two orders of magnitude higher than commercial Co3O4 . Theoretical models show that oxygen vacancies (17.7%) at exposed {112} facet on the carbon interface take superiority in nanocubic spinel phase, which allows reactive species to be strongly adsorbed on nanostructured catalysts' surface and plays key roles in hindering deactivation under moisture rich conditions. The progresses offer a promising way in the development of novel spinel oxides with tailored architecture and properties for vast applications.

Designing MOF Nanoarchitectures for Electrochemical Water Splitting

“…The pyrolysis of MOFs with ordered calcination modulates various characteristics, such as conductivity and porosity, surface area, stability, and catalytic activity; hence, such derivatives are highly interesting for water splitting. [23][24][25][26][27][28][29][30] Based on these guidelines, diverse MOF-based/derived materials have been reported in the past five years. However, a comprehensive review summarizing MOF-based/derived materials with well-defined synthetic methods, chemical compositions, nanostructured morphologies, electrocatalytic activities, and reaction mechanisms is urgently needed to provide strong inspiration and direct future developments in engineering MOFbased/derived electrocatalysts for water splitting.…”

Crystal Facet Induced Single‐Atom Pd/CoxOy on a Tunable Metal–Support Interface for Low Temperature Catalytic Oxidation

“…The morphology control of catalyst provides a good opportunity to improve the catalytic properties and enhance its efficiency. [ 17,25–28 ] To confirm the tunable structures of catalysts, we initially focused on the morphological properties of Co x O y nanoarrays. Scanning electron microscope (SEM) images reveal that crystal shape and size of Co x O y nanoarrays are very sensitive toward reaction temperature.…”

Nanocage‐Shaped Co3−xZrxO4 Solid‐Solution Supports Loaded with Pt Nanoparticles as Effective Catalysts for the Enhancement of Toluene Oxidation

“…The observed enhanced catalytic activity of 2.0 wt% Pt/Co 2.73 Zr 0.27 O 4 is suggested to result from the formation of abundant oxygen vacancies and higher Co 2+ /Co total ratios. [ 37 ] Figure 6d presents the Arrhenius plots for toluene combustion over the Co 3 O 4 , Co 2.73 Zr 0.27 O 4 , 0.5 wt% Pt/Co 2.73 Zr 0.27 O 4 , 1.0 wt% Pt/Co 2.73 Zr 0.27 O 4 , and 2.0 wt% Pt/Co 2.73 Zr 0.27 O 4 samples at a weight hourly space velocity of 36 000 mL h −1 g −1 . Comparison of the apparent E a values shows Co 2.73 Zr 0.27 O 4 ( E a = 98.69 kJ mol −1 ) and 2.0 wt% Pt/Co 2.73 Zr 0.27 O 4 ( E a = 66.18 kJ mol −1 ) to have lower E a values compared with Co 3 O 4 , which further implies enhanced performance toward the catalytic oxidation of toluene.…”

“…The observed enhanced catalytic activity of 2.0 wt% Pt/Co 2.73 Zr 0.27 O 4 is suggested to result from the formation of abundant oxygen vacancies and higher Co 2+ /Co total ratios. [37] Figure 6d presents , which further implies enhanced performance toward the catalytic oxidation of toluene. [38,39] Furthermore, the comparison of the temperature at which 90% toluene is converted is presented in Figure 6c.…”