Hydrogen Adsorption on Palladium and Platinum Overlayers: DFT Study

Table 1

The d-band centers (𝐸_d-band), the preferential adsorption sites for H adsorption, and the energies of hydrogen adsorption (𝐸_ads) on studied surfaces. Both palladium and platinum surfaces are divided by bolded lines in three groups, depending on their exposition to the compressive strain (the first group), the absence of the surface strain (the second group), or the presence of the tensile strain (the third group).

Palladium surface				Platinum surfaces
Label	𝐸d-band/eV	Adsorption site	𝐸ads/eV	Label	𝐸d-band/eV	Adsorption site	𝐸ads/eV
PdML/Cu(111)	−2.42	hcp	0.10	PtML/Cu(111)	−2.82	atop	0.40
				(PtML)2/Cu(111)	−2.62	atop	−0.05
(PdML)2/Cu(111)	−2.09	fcc	−0.16	PtML/Pd(111)	−2.15	fcc	−0.38
				(PtML)2/Pd(111)	−2.42	fcc	−0.39
Pd(111)	−1.71	fcc	−0.48	Pt(111)	−2.13	fcc	−0.43
Cuund/Pd(111)	−1.76	fcc	−0.40	Cuund/Pt(111)	−2.14	fcc	−0.18
Ptund/Pd(111)	−1.81	fcc	−0.49	Pdund/Pt(111)	−2.10	fcc	−0.41
Auund/Pd(111)	−1.63	fcc	−0.46	Auund/Pt(111)	−1.91	fcc	−0.39
PdML/Pt(111)	−1.80	fcc	−0.51	PtML/Au(111)	−1.75	fcc	−0.60
(PdML)2/Pt(111)	−1.68	fcc	−0.51
PdML/Au(111)	−1.37	fcc	−0.60	(PtML)2/Au(111)	−2.02	fcc	−0.58
(PdML)2/Au(111)	−1.50	fcc	−0.62