TY - JOUR
T1 - Pt-Assisted Carbon Remediation of Mo2C Materials for CO Disproportionation
AU - Sikorski, Ember
AU - Li, Lan
AU - Fang, Zongtang
AU - Wang, Lu Cun
AU - Wang, Yixiao
AU - Tan, Shuai
AU - Li-Oakey, Katie Dongmei
AU - Yablonsky, Gregory
AU - Dixon, David A.
AU - Fushimi, Rebecca
N1 - Fang, Zongtang; Wang, Lu-Cun; Wang, Yixiao; Sikorski, Ember; Tan, Shuai; Li-Oakey, Katie Dongmei; . . . and Fushimi, Rebecca. (2020). "Pt-Assisted Carbon Remediation of Mo2C Materials for CO Disproportionation". ACS Catalysis, 10(3), 1894-1911. https://doi.org/10.1021/acscatal.9b05225
PY - 2020/2/7
Y1 - 2020/2/7
N2 - Using the CO disproportionation (Boudouard) reaction as a probe reaction, an in-depth analysis of temperature-programmed pulse response data shows that the addition of Pt to Mo 2 C mitigates deactivation of Mo active sites by acting as a carbon collector. CO 2 production on Mo 2 C and Pt/Mo 2 C materials is dependent on both the activation energy and the CO surface concentration. Detailed plane-wave density functional theory calculations of the CO adsorption and disproportion reactions on Mo 2 C-supported Pt nanoparticles (NPs) are reported. The Mo 2 C was modeled by the β -Mo 2 C (100) surface, and the Pt/Mo 2 C interface was modeled by the addition of 12 Pt atoms to the Mo2C (100) surface (12Pt@Mo 2 C). The potential energy surfaces of the Boudouard reaction were calculated on pure Mo 2 C, 12Pt@Mo 2 C, and Pt (111) surfaces. CO dissociation readily occurs on the Mo 2 C (100) surface, but not on the Pt (111) surface, with the former being exothermic and the latter being endothermic. At the Pt/Mo 2 C interface, CO dissociation is still exothermic, but with a larger energy barrier. The Boudouard reaction takes place on the Mo 2 C region, where CO 2 is formed from a surface O atom dissociated from one CO molecule in reaction with another CO molecule, leaving one C atom on the surface. C adsorption is preferential on the Pt site in comparison to the Mo site. The supported Pt domains can collect the remaining C atoms, facilitating further CO 2 formation on the active Mo sites. A Bader charge analysis shows that the surface metal−carbon bond is a mixture of covalent and ionic bonds, whereas the surface metal−oxygen bond is ionic. Electron localization function (ELF) and partial charge density calculations agree well with the Bader charge analysis. These computational results are consistent with experimental observations of the interaction of CO with Mo 2 C nanotube supported Pt domains in the transient regime under far from equilibrium conditions. The Boudouard reaction is an important side reaction, and the unexpected role found for Pt as a carbon collector, with Mo serving as a disproportionation site, provides a unique vantage point for understanding carbon and coke formation on catalytic materials.
AB - Using the CO disproportionation (Boudouard) reaction as a probe reaction, an in-depth analysis of temperature-programmed pulse response data shows that the addition of Pt to Mo 2 C mitigates deactivation of Mo active sites by acting as a carbon collector. CO 2 production on Mo 2 C and Pt/Mo 2 C materials is dependent on both the activation energy and the CO surface concentration. Detailed plane-wave density functional theory calculations of the CO adsorption and disproportion reactions on Mo 2 C-supported Pt nanoparticles (NPs) are reported. The Mo 2 C was modeled by the β -Mo 2 C (100) surface, and the Pt/Mo 2 C interface was modeled by the addition of 12 Pt atoms to the Mo2C (100) surface (12Pt@Mo 2 C). The potential energy surfaces of the Boudouard reaction were calculated on pure Mo 2 C, 12Pt@Mo 2 C, and Pt (111) surfaces. CO dissociation readily occurs on the Mo 2 C (100) surface, but not on the Pt (111) surface, with the former being exothermic and the latter being endothermic. At the Pt/Mo 2 C interface, CO dissociation is still exothermic, but with a larger energy barrier. The Boudouard reaction takes place on the Mo 2 C region, where CO 2 is formed from a surface O atom dissociated from one CO molecule in reaction with another CO molecule, leaving one C atom on the surface. C adsorption is preferential on the Pt site in comparison to the Mo site. The supported Pt domains can collect the remaining C atoms, facilitating further CO 2 formation on the active Mo sites. A Bader charge analysis shows that the surface metal−carbon bond is a mixture of covalent and ionic bonds, whereas the surface metal−oxygen bond is ionic. Electron localization function (ELF) and partial charge density calculations agree well with the Bader charge analysis. These computational results are consistent with experimental observations of the interaction of CO with Mo 2 C nanotube supported Pt domains in the transient regime under far from equilibrium conditions. The Boudouard reaction is an important side reaction, and the unexpected role found for Pt as a carbon collector, with Mo serving as a disproportionation site, provides a unique vantage point for understanding carbon and coke formation on catalytic materials.
KW - Boudouard reaction
KW - Pt-assisted carbon remediation
KW - Pt/Mo2C interface
KW - deactivation mitigation
KW - density functional theory
KW - transient kinetics
KW - Pt/MoC interface
UR - https://scholarworks.boisestate.edu/mse_facpubs/419
UR - https://doi.org/10.1021/acscatal.9b05225
UR - http://www.scopus.com/inward/record.url?scp=85078682883&partnerID=8YFLogxK
U2 - 10.1021/acscatal.9b05225
DO - 10.1021/acscatal.9b05225
M3 - Article
VL - 10
SP - 1894
EP - 1911
JO - ACS Catalysis
JF - ACS Catalysis
IS - 3
ER -