Pseudopyrolysis of Metal–Organic Frameworks: A Synchronous Nucleation Mechanism to Synthesize Ultrafine Metal Compound Nanoparticles

Abstract

Metal−Organic frameworks (MOFs) are increasingly being investigated for the synthesis of carbon-supported metal-based ultrafine nanoparticles (UNPs). However, the collapse of the carbon framework and aggregation of metal particles in the pyrolysis process have severely hindered their stability and applications. Here, we report the synchronous nucleation pseudopyrolysis of MOFs to confine Fe/FeO x UNPs in intact porous carbon nanorods (IPCNs), revealed by in situ transmission electron microscopy experiments and ex situ structure analysis. The pseudopyrolysis mechanism enables strong physical and chemical confinement effects between UNPs and carbon by moderate thermal kinetics and abundant oxygen defects. Further, this strong confinement is greatly beneficial for subsequent chemical transformations to obtain different Fe-based UNPs and excellent electrochemical performance. As a proof of concept, the as-prepared FeSe UNPs in IPCNs show superior lithium storage performance with an ultrahigh and stable capacity of 815.1 mAh g −1 at 0.1 A g −1 and 379.7 mAh g −1 at 5 A g −1 for 1000 cycles.

Encapsulation of TixFeyLamOz nanoparticles into NH2-MIL-125(Ti) to fabricate a promising photocatalyst for the C–N coupling reaction

“…34,35 Using the functionalized cavities of MOFs as active sites for metal nanoparticles seems promising for the development of highperformance heterogeneous catalysts. 36 Recently, new properties have led to an increase in the encapsulation of nanoparticle MOFs 37 as a result of the synergistic effect between two functional materials, [38][39][40] and they tend to show higher activity and increased selectivity compared to their pristine counterparts. The encapsulation of noble-free nanoparticles in a MOF is a relatively new branch in the MOF family, and can be performed for those MOFs that exhibit excellent shape and selective catalytic performance in organic reactions.…”

“…34,35 Using the functionalized cavities of MOFs as active sites for metal nanoparticles seems promising for the development of high-performance heterogeneous catalysts. 36…”

Hierarchical Co1.4Ni0.6P@C hollow nanoflowers assembled from ultrathin nanosheets as an anode material for high-performance lithium-ion batteries

“…With the rapid development of modern society, energy storage devices with high energy and high power density are urgently needed in the fields of electronics, electric vehicles and smart grids. 1,2 In particular, lithium-ion batteries (LIBs) with high energy density and long cycle life are desirable for large-scale equipment operation. 3 However, the commercial graphite anode with low specific capacity (372 mA h g −1 ) limits the development of high energy density batteries and cannot meet the growing demand for energy storage.…”

Bi nanoparticles confined in N,S co-doped carbon nanoribbons with excellent rate performance for sodium-ion batteries

“…In the past few decades, lithium-ion batteries (LIBs) have played an important role in popularizing portable electronics and in the rise of transport electrification due to their high energy density, power density and long cycling stability. 1,2 However, the limited resources and uneven distribution of lithium mean that its price is too high for it to be applicable in large-scale storage. 3 It is urgent to develop alternative and low-cost batteries to meet the ever-growing demand.…”