Improving the Electrocatalytic Activities and CO Tolerance of Pt NPs by Incorporating TiO2 Nanocubes onto Carbon Supports

Jhon Quiroz,Rodolfo M. Antoniassi,Pedro. H. C. Camargo,Eduardo C. M. Barbosa,Luanna S. Parreira,Roberta A. Isidoro,Julio C. M. Silva,Estevam V. Spinacé

doi:10.1002/cctc.202002066

Abstract

AbstractDesigning efficient anode CO‐tolerant electrocatalysts is critical in low‐temperature fuel cell catalysts fueled either by H2/CO or alcohol. We demonstrate that the incorporation of TiO2 nanocubes (TiO2NCs) on Carbon Vulcan supports, followed by the synthesis of Pt NPs at their surface (Pt/TiO2NCs‐C material), led to improvements in performance towards the electrooxidation of carbon monoxide, ethanol, methanol, ethylene glycol, and glycerol in acidic media relative to the commercial Pt/C and Pt/TiO2‐C counterparts employing commercial TiO2. The nanocubes enabled changes in the electronic properties of Pt NPs while contributing to the bifunctional mechanism as compared to Pt/C and Pt/TiO2‐C with commercial TiO2. Fuel cell experiments fed with H2/CO steam showed that Pt/TiO2NCs‐C employing nanocubes was resistant to CO‐poisoning, yielding superior performance in operational conditions. The results reported herein have important implications for developing electrocatalysts with superior performances in PEMFCs.

Highlights

Fuel cell experiments fed with H2/CO steam showed that Pt/TiO2NCs-C employing nanocubes was resistant to CO-poisoning, yielding superior performance in operational conditions
It can be observed that the TiO2 nanocubes are well defined, relatively monodisperse, and their edge lengths corresponded to 72 9 nm
The 0.36 nm lattice spacings characteristic of TiO2 anatase can be detected, corresponding to the growth along the (100) crystallographic direction and the exposure of (100) surface facets in agreement with the nanowhere QH is the hydrogen desorption charge from 0.05–0.4 V, considering the electrical double layer contribution; [Pt] is the platinum loading and q0H is the charge required to oxidize a hydrogen monolayer adsorbed over platinum (210 μC cm 2)

Summary

A.I. Virtasen aukio 1

We targeted the addition of TiO2 nanocubes (TiO2NCs) onto carbon and employed the resulting material as hybrid support for the deposition of Pt NPs, which was subsequently evaluated as an electrocatalyst towards carbon monoxide, methanol, ethanol, ethylene glycol, glycerol, and CO-contaminated H2 electrooxidation. Pt NPs supported on TiO2NCs-C and TiO2-C materials were prepared by a modified alcohol reduction method.[43] In a typical synthesis, a suspension containing. The following materials were used as received: analytical grade hexachloroplatinic (IV) acid hexahydrated (H2PtCl6 · 6H2O, 99.9 %, Sigma-Aldrich) as metal precursor, Carbon Vulcan (XC72R, 99 %, Cabot Corporation), DI water (18.2 MΩcm), H2SO4 (sulfuric acid PA, Casa Americana), Nafion solution 5 wt.%, Sigma-Aldrich, Nafion membrane 115 (Dupont), C3H7O (anhydrous isopropyl alcohol, 99.5 %, Sigma-Aldrich), CH4O (absolute methanol, Sigma-Aldrich), C2H6O2 (absolute ethanol, Sigma-Aldrich), C2H6O2 (ethylene glycol, 99.5 %, Vetec) and C3H8O3 (glycerol, 99 %, Sigma-Aldrich), C2H4O2. Polarization curves were employed to evaluate the catalyst‘s electrical performance

Results and discussion

Conflict of Interest

Conclusions