Understanding Uptake of Pt Precursors During Strong Electrostatic Adsorption on Single-Crystal

Supplementary Material for:

Understanding Uptake of Pt Precursors During Strong Electrostatic Adsorption on Single-Crystal Carbon Surfaces

Grant S. Seuser1, Ritubarna Banerjee2, Gift Metavarayuth1, Amy J. Brandt1, Thathsara D. Maddumapatabandi1, Stavros Karakalos2, Ye Lin2, John R. Regalbuto2 and Donna A. Chen1*

1Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208

Phone: 803-777-1050, Fax: 803-777-9521, Email:

2Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208

*Corresponding Author

Vendors for high surface area supports

Vendors for the carbon and metal oxide supports used for experiments in Figure 8 and Figure S1 are as follows: Darco G60 (Cabot Corporation), Ketjen Black EC300 (Akzo Normal), Timrex HSAG 300 (Imerys Graphite and Carbon), Darco S51 (Cabot Corporation), and Darco KBM (Cabot Corporation). Vendors for the oxide supports were: Aerosil 300 hydrophilic fumed silica (Evonik Industries) andPuralox/Catalox -alumina SBa200 (Sasol).

Table S1. Experimental details for SEA studies.

Precursor / Support / PZC / pH
(initial) / Concentration
(ppm) / Experiment / Associated
Figure
H2[PtCl6] / HOPG / --- / 2.5a / 100 / XPS / 2a
H2[PtCl6] / GNPs / 7-8 / 3 / 300 / XPS / 2b
H2[PtCl6] / HOPG / --- / 2.5a / 100 / AFM / 3
H2[PtCl6] / GNPs / 7-8 / 3 / 300 / STEM / 4
[Pt(NH3)4](OH)2 / HOPG / ---- / 11 / 100 / XPS / 5a
[Pt(NH3)4](OH)2 / GNPs / 7-8 / 11.5b / 300 / XPS / 5b
[Pt(NH3)4](OH)2 / HOPG / ---- / 11 / 100 / AFM / 6
[Pt(NH3)4](OH)2 / GNPs / 7-8 / 11 / 300 / STEM / 7
Na2[PtCl4] / HOPG / ---- / 2.2 / 100 / XPS / 8a, i
Na2[PtCl4] / GNPs / 7-8 / 3 / 300 / XPS / 8a, ii
Na2[PtCl4] / Darco G60 / 8.5 / 3 / 300 / XPS / 8a, iii
Na2[PtCl4] / Ketjen black / 9.4 / 3 / 200 / XPS / 8a, iv
[Pt(NH3)4](OH)2 / Timrex HSG300 / 4.5 / 11 / 300 / XPS / 8b, i
[Pt(NH3)4](OH)2 / Darco S51 / 4.7 / 11 / 300 / XPS / 8b, ii
[Pt(NH3)4](OH)2 / Darco KBM / 2.8 / 11 / 300 / XPS / 8b, iii
[Pt(NH3)4](Cl)2 / Silica / 4.1c / 11 / 300 / XPS / None
Na2[PtCl4] / -Alumina / 8.3c / 3 / 200 / XPS / None

aAlthough the absolute uptakes of H2[PtCl6]on HOPG may depend on pH (2.5 vs. 3), the uptake trends as a function of pH are the same on the untreated and HCl-treated GNP surfaces (Figure S2a).

bBased on the uptake vs. pH curve for [Pt(NH3)4](OH)2 on GNPs, the uptakes are nearly identical at pHs of 11 and 11.5 (Figure S2b).

cInitial and final pHs during SEA were the same except on silica and alumina, where the final values were 8.7 and 4.2, respectively.

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