(544el) CO Oxidation By Single-Atom Pt Catalyst Anchored to Ni-Doped MgO

Single-atom catalysts (SAC) made of isolated noble metal atoms have recently attracted huge attention in the field of heterogeneous catalysis. SACs not only provide enhanced catalytic activity and selectivity, it reduces the overall cost drastically [1,2]. However, proper anchoring of the metal atoms on the surface of a support material still remains challenging as the isolated atoms are highly mobile in nature [3,4]. Our work intends to solve the problem of binding single metal atoms on stable oxides by doping them with transition metals. We have carried out a density functional theory based study of the catalytic activity of Pt single atoms on Ni-doped MgO support for CO oxidation. Our calculations revealed that Pt atoms can bind well on MgO{001} surface when doped with Ni at the subsurface interstitial. The binding of Pt on Ni-doped MgO is much stronger with a binding energy of -3.96 eV compared to -2.23 eV reported for surface oxygen sites of pristine MgO [5]. Our calculated adsorption energy of CO molecule on the Pt atom is comparable to other Pt systems that are known to be catalytically active. To investigate the catalytic activity of the system, the minimum energy pathway and the reaction barriers for all the elementary steps of CO oxidation were also calculated within the DFT framework. Our calculations suggest that isolated Pt atoms anchored on MgO {001} surface via subsurface Ni doping provides good catalytic activity for CO oxidation.

Fig: CO adsorption on Pt atoms anchored on Ni-doped MgO support. The orange, red, gray, silver and brown atoms represent Mg, O, Ni, Pt and C respectively.

References

[1] N. Cheng, et. al, Nature Communications 7 (2016) pp–3638.

[2] S. Sun, et. al, Scientific Reports 3 (2013) pp–1775.

[3] X. F. Chen, J. M. Yan, and Q. Jiang, J. Phys. Chem. C 118, (2014) pp–2122−2128.

[4] J. Jones, et. al, Science 353, Issue 6295, (2016) pp–150-154.

[5] H. Xu, C. Xu, D. Cheng and J. Li, Catal. Sci. Technol. 7, (2017) pp–5860.