Colloidal Syntheses of Shape- and Size-Controlled Pt Nanoparticles for Electrocatalysis Christophe Coutanceau & Patrick Urchaga & Sylvain Brimaud & Stève Baranton Published online: 31 January 2012 # Springer Science+Business Media, LLC 2012 Abstract Different colloidal synthesis methods of platinum nanoparticles with controlled sizes and shapes that are rele- vant for electrocatalysis studies are reviewed. Four main methods, i.e., water in oil microemulsion (w/o) method, polyacrylate (PA) method, tetradecyltrimethylammonium bromide (TTAB) method, and ethylene glycol method, are used to synthesize platinum nanoparticles. The PA method allowed us to synthesize reproducibly nanocubes, nanoocta- hedrons, or nanocuboctahedrons/truncated nanooctahedrons with size between 8 and 10 nm, the TTAB method led to the synthesis of nanocubes of about 10 nm, and the w/o method allowed the synthesis of spherical particles of about 3 nm. All these samples could be cleaned for further electrochem- ical characterization of their surface structure by hydrogen underpotential deposition and by spontaneous deposition and oxidation of bismuth and germanium, leading to a quantitative determination of the (100) and (111) surface domains. The samples prepared by the ethylene glycol method, in the presence or not of polyvinylpyrrolydone as surfactant, were size or shape controlled, but did not allow the electrochemical characterization of their surface due to remaining of strongly adsorbed organic species even after cleaning steps. Keywords Colloidal synthesis . Electrochemistry . Nanoparticles . Platinum . Shape controlled . Size controlled Introduction Because metal nanoparticles have specific properties differ- ing from those of massive materials, they have found nu- merous applications in chemistry, electronics, optics, information storage, biotechnology, sensors, etc. One of the most important applications of metal nanoparticles con- cerns the field of heterogeneous catalysis. In heterogeneous catalysis, the chemical reaction occurs at the catalytic mate- rial surface, and atoms from the core are not directly in- volved. Moreover, costly catalytic materials, such as noble metals, are often used. In particular, reactions occurring in proton exchange membrane fuel cells, i.e., hydrogen, carbon monoxide, or alcohol oxidation reactions and oxygen reduc- tion reaction, are up to now catalyzed by platinum based materials. In such case, there is a real interest for obtaining the highest catalytic surface area from a low metal weight. Thus, numerous applications such as vehicle exhaust treat- ment, industrial effluent treatment, petro-chemistry, fuel cells, etc., are using noble metal nanoparticles for catalyzing the transformation processes of chemical compounds at acceptable costs. It has been proposed that the main characteristics condi- tioning the electronic, optical, magnetic, and catalytic prop- erties could be the size and shape of the nanoparticles [1]. These specific properties are usually attributed to the high proportion of metal atoms at the surface with respect to the total number of atoms in the nanoparticle [2]. Indeed, for nanometric particles (diameter d <10 nm), the proportion of surface atoms is very high, being about 20% for d 0 5 nm (with a total number of about 6,000 atoms) and about 50% C. Coutanceau (*) : P. Urchaga : S. Brimaud : S. Baranton IC2MP (Institut de Chimie des Matériaux et des Milieux de Poitiers), Université de Poitiers, 4 rue Michel Brunet, B 27, 86022 Poitiers Cedex, France e-mail: christophe.coutanceau@univ-poitiers.fr Present Address: S. Brimaud Institute of Surface Chemistry and Catalysis, Ulm University, 89069 Ulm, Germany Electrocatal (2012) 3:75–87 DOI 10.1007/s12678-012-0079-0