Abstracts Book - IMRC 2018

• SF3-O006 Invited Talk
THE PROMOTION OF MoS2 WITH Co AND Ni SOLVED
Russell R. Chianelli 1
1 University of Texas at El Paso, MRTI-Chemistry, United States.
As environmental regulations increase, more selective transition metal sulfide
(TMS) catalytic materials for hydrotreating applications are needed. Highly active
TMS catalysts become more and more desirable triggering new interest for
unsupported Co-promoted MoS 2 -based systems that have high volumetric
activity as reported here. Contrary to the common observation for aluminasupported
based catalysts, we found in our previous studies with
dibenzothiophene (DBT) hydrodesulfurization (HDS) that the catalytic activity is
directly proportional to the increase of surface area of the sulfide phases (Co 9 S 8
and MoS 2 ) present in Co-promoted MoS 2 unsupported catalysts. This suggests
that activity is directly connected with an increase of the contact surface area
between the two sulfide phases. Understanding of the nature of the possible
interaction between MoS 2 and Co in unsupported catalytic systems is therefore
critical in order to get a more generalized overview of the causes for synergy.
This has been achieved herein through the detailed characterization by XRD,
XPS, and HRTEM of the highly active resulting in a proposed model for a
interface. This model was then subjected to a DFT analysis to determine a
reasonable description of the surface contact region between the two bulk
phases. Modeling of the interface shows the creation of open latent vacancy
sites on Mo atoms interacting with Co and formation of direct Co–Mo bonds.
Strong electron donation from Co to Mo also occurs through the intermediate
sulfur atom bonded to both metals while an enhanced metallic character is also
found. These changes in coordination and electronic properties are expected to
favor a synergetic effect between Co. Thus, understanding and optimization of
the promotion phases: Co 9 S 8 and MoS 2 and related systems (Ni 3 S 2 /WS 2 ), is now
complete.
Acknowledgment:
The University of Texas at El Paso and NSF-Materials Division.
Keywords: MoS2, Catalytic, Materials
Presenting authors email: chianell@utep.edu