Tailored Pt Coatings on Metallic Tin—An Effective Catalyst for Fuel Cells Anodes

Abstract

A thin Pt layer supported on tin (Sn) is suggested as a catalyst with greater CO tolerance for fuel cell anode applications. DFT calculations of the adsorption energy of one CO molecule on one Pt monolayer supported on seven monolayers of Sn show significantly higher values (−1.04 eV/molecule), in comparison with the adsorption energy on 2, 3, and 5 monolayers and metallic Pt(111) (−1.82 – −1.92 eV/molecule). For full CO coverage, the adsorption energy is larger (less negative) in comparison with monometallic Pt (−0.93 eV/molecule) for one (−0.55 eV/molecule) and even two monolayers (−0.83 eV/molecule). Correlation between Eads–adsorption energy and Pt d-band center (εd) was found for full coverage of CO. Cyclic voltammetry supports the conclusion that CO is weakly bound on a thin Pt layer coated on metallic Sn. Unlike CO adsorption, methanol adsorption energies on Pt are not affected by the supporting tin (−0.695 eV/molecule for MeOH/Pt1/Sn7 in comparison to −0.690 eV/molecule for MeOH/Pt). Thus, a very thin layer of Pt supported on Sn can prevent CO adsorption and may function as an effective catalyst for fuel cells.

The origins of formic acid electrooxidation on selected surfaces of Pt, Pd, and their alloys with Sn

“…The CO oxidation onset potential of Pd 3 Sn/C is around 140 mV higher than Pt 3 Sn/C and Pt 3 Pd 3 Sn 2 /C, which indicates that the electronic effect of Sn is more pronounced in a Pt-containing catalyst, in line with the DFT results and reported in our previous paper. 53 CO oxidation occurred on a broader potential range consistent with previous reports. 7 The two oxidation peaks observed for Pt 3 Sn/C are attributed to the oxidation of CO on two different sites.…”

Chemical-Dealloying-Derived PtPdPb-Based Multimetallic Nanoparticles: Dimethyl Ether Electrocatalysis and Fuel Cell Application

“…The adsorption energies of DME and CO on Pt 2 PdPb 2 (pristine) and Pt 2 PdPb (acid-washed) catalysts in comparison to those of other catalyst surfaces are given in Table . , Comparing the adsorption energies of DME and CO on Pt 2 PdPb with those on Pt(111) leads to the conclusion that the alloying of Pd and Pb with Pt chemically modifies the surfaces and helps weaken the adsorption of these species. Hence, DME oxidation became more facile on the Pt 2 PdPb surface because of weaker adsorption.…”