Experimentally Probing Ligand-Strain Effect Via a Novel Catalyst Platform

In this presentation, a novel catalyst fabrication platform was designed and investigated. Using a phase-pure transition metal carbide (TMC) nanotube as support [1], noncontiguous platinum group metal (PGM) particles were deposited from atomic level to 2-3 nanometers (nm) onto the TMC support by atomic layer deposition [2]. This platform enables experimental investigation on ligand-strain effect of resultant PGM/TMC catalysts. Characterization of metal-adsorbates bond strength, via diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) [3] and temperature-programmed oxidation (TPO), informs catalyst surface properties and model reaction mechanism [4]. Temporal analysis of products (TAP) technique was first applied to this catalyst platform revealing the existence of different active sites for Pt particle sizes (<3 nm). Additionally, the correlation between catalyst reactivity and change of deposited particle size was further investigated using water-gas-shift (WGS) reaction. The rarely investigated PGM particle size range and the ease of surface characterization by high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and other techniques, provides a unique PGM/TMC platform, which can be utilized closely with theoretical predictions to further our understanding on the interaction between PGM and non-PGM metals.

References

[1] Wan, C.; Regmi, Y. N.; Leonard, B. M. Angew. Chemie Int. Ed. 2014, 53(25), 6407–6410.

[2] McCormick, J. A.; Cloutier, B. L.; Weimer, A. W.; George, S. M. J. Vac. Sci. Technol. A Vacuum, Surfaces, Film. 2007, 25(1), 67.

[3] Ding, K.; Gulec, A.; Johnson, A. M.; Schweitzer, N. M.; Stucky, G. D.; Marks, L. D.; Stair, P. C. Science. 2015, 350 (6257), 1688–1690.

[4] Schweitzer, N. M.; Schaidle, J. a; Ezekoye, O. K.; Pan, X.; Linic, S.; Thompson, L. T. J. Am. Chem. Soc. 2011, 133, 2378–2381.