Issue 32/2015 - Novel nanocatalysts were prepared by ALD technology used in Shanxi Coal

It was learned from the Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences, that the research team led by Qin Yong, a researcher at the State Key Laboratory of Coal Conversion, used ALD technology to design and prepare a Ni-based hydrogenation catalyst
with multiple limits.
Compared with the unconfined catalyst, the activity and stability of the Ni-based catalyst with multiple confinement for the hydrogenation catalytic reaction of cinnamaldehyde and nitrobenzene are significantly improved
.

Atomic layer deposition (ALD) is an advanced thin film deposition technique
.
Using the technical characteristics and advantages of ALD, new high-efficiency nanocatalysts can be designed and synthesized, and the surface interface structure
of the catalyst can be accurately adjusted.
The interface structure of the metal-oxide support strongly affects the performance of
heterogeneous catalysts.
Precise design and control of interface structure is very important
for the preparation of new and efficient catalysts.

The research team used ALD technology to first deposit NiO nanoparticles on the surface of the template using carbon nanospirals or carbon nanotubes as a template, and then deposited Al2O3 nanofilms, and after calcination and reduction treatment, Ni-in-ANTs coated with alumina nanotubes (ANT)
were obtained.
This approach allows Ni particles to be confined not only in alumina nanotubes, but also embedded in pits in the inner walls of alumina nanotubes, called multiple confinements
.
The deposition order of NiO nanoparticles and Al2O3 nanofilms was changed, and Ni-out-ANTs were prepared by calcination and reduction treatment
.
A large number of characterization results show that the two have the same Ni content, Ni nanoparticle size, alumina nanotube wall thickness, pore structure and Ni reduction.

However, for cinnamaldehyde and nitrobenzene-catalyzed hydrogenation, Ni-based multiplex confinement catalysts are much more active than unconfined catalysts
.
This is due to the fact that the Ni particles in the confined catalyst are confined in the pit of the inner wall of the alumina nanotube, which has more Ni-Al2O3 interface sites, and the metal-support interaction is stronger, which promotes the hydrogen overflow phenomenon, thereby improving the hydrogenation reaction activity
of the catalyst.
In addition, alumina nanotubes can protect the Ni particles in the confinement and prevent them from falling off and dissolving in the reaction, so that the multiplex confinement catalyst has better recycling stability
than the unconfined catalyst.

This method has universal applicability and can be used to synthesize confinement catalysts of other systems for catalyzing different reactions, which provides an important scientific reference
for the design of high-efficiency nanocatalysts in the future.
(Section)