A chemical nanostructure developed by Boston College researchers behaves much like the pores of the skin, serving as a precise control for a typically stubborn method of catalysis that is the workhorse of industrial chemistry.
Boston College researches started with a metallic crystal. It was then coated with a "sacrificial layer" of copper oxide. The application of ZIF-8 formed a porous skin that then etched away the copper. Within the resulting cavity, researchers were able to control the chemical reaction thanks to the skin-like shell of ZIF-8.
Credit: Journal of the American Chemical Society
Scientists have been trying to develop so-called yolk-shell catalysts as a means of imparting greater selectivity on heterogeneous catalysis, a process used in most industrial chemistry, including the manufacture of fine chemicals, petrochemicals and agrochemicals.
Boston College Assistant Professor of Chemistry Chia-Kuang Tsung and his team developed a nanostructure that can regulate chemical reactions thanks to a thin, porous skin capable of precisely filtering molecules based on their size or chemical make-up, the group reported recently in the Journal of the American Chemical Society.
"The idea is to make a smarter catalyst," said Tsung. "To do that, we placed a layer of 'skin' on the surface that can discriminate between which chemical reacts or does not react with the catalyst."The team started with a nanoscale metallic crystal, then applied a "sacrificial layer" of copper oxide over it, Tsung said. Next, a shell of highly refined material known as a metal-organic framework, or MOF, was applied to the structure. Immediately, the polycrystalline MOF adhered to the cooper oxide, forming and outer layer of porous "skin". At the same time, the MOF began to etch away the copper oxide layer from the surface of the crystal, creating a tiny chamber between the skin and the catalyst where the chemical reaction can take place.
Tsung said the unprecedented level of control is a significant step in the use of unique nanoscale chemical structures in the effort to impart greater selectivity and control on heterogeneous catalysis, a proven process used to create chemicals in nearly all areas outside of pharmaceutical research, which employs homogeneous catalysis.
Scientists have been looking for ways to exert greater selectivity in heterogeneous catalysis in an effort to expand its application and extend "green chemistry" benefits of reduced byproducts and waste, Tsung said.
The key to the nanocrystal is the extremely precise structure of the metal-organic framework, Tsung said, which gives the skin an intricate network of pore-like passages through which select gases or liquids can pass before contacting the catalyst and triggering the desired reaction.
"We can make these pores very precisely, just like your skin or like the membrane surrounding a cell," Tsung said. "We can change their composition and chemical properties in order to accept or reject certain types of reactions. That is a level of control chemists in a variety of fields are eager to see nurtured and refined."
Ed Hayward | EurekAlert!
Newly designed molecule binds nitrogen
23.02.2018 | Julius-Maximilians-Universität Würzburg
Atomic Design by Water
23.02.2018 | Max-Planck-Institut für Eisenforschung GmbH
A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.
In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...
A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.
By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
23.02.2018 | Physics and Astronomy
23.02.2018 | Health and Medicine
23.02.2018 | Physics and Astronomy