Graphene Based Electrocatalysts for PEM Fuel Cells: Challenges and Perspectives

Polymer electrolyte membrane (PEM) fuel cells are attractive for various applications due to their high efficiency and low operation temperatures. Platinum (Pt) nanoparticles, used as catalyst in PEM fuel cells, have high cost, performance and durability problems; and low abundance. Catalyst support materials are of great importance in regulating the properties of catalyst nanoparticles such as shape, size, and dispersion. Carbon black, the most commonly used commercial catalyst support, has several limitations which cause the degradation of catalyst activity and performance. Graphene, as a unique single-atom thick layered structure of carbon, possesses excellent electrical, thermal and mechanical properties. Moreover, the previous reports have revealed that graphene and its derivatives could be used as highly efficient electrodes in various energy related applications. However, the ultimate extent of graphene based materials in energy applications, especially in fuel cells, is yet not to be found. In addition, the crucial role of graphene-based materials in providing the reliable solid-state support for platinum nanoparticles for fuel cells should be noted [1]. In the present work, various graphene based materials including graphene oxide (GO), graphene nanoplatelets, functionalized graphene and graphene hybrids have been utilized as the catalyst support [1]. Graphene supported Pt nanoparticles were synthesized by means of impregnation-reduction, microwave-assisted deposition and photocatalytic deposition methods. Well dispersed and uniformly decorated Pt nanoparticles with a small particle size (2-3 nm) on graphene and its derivatives are obtained by impregnation-reduction and microwave-assisted deposition methods [2]. Moreover, substantially enhanced electrocatalytic activity and fuel cell performances for graphene-based electrocataalysts, compared to commercial carbon black based systems, were achieved. Furthermore, the use of graphene hybrids as the catalyst support resulted in a significant improvement in both catalytic activity and catalyst utilization in PEM fuel cells. In addition, we have successfully modified the electronic band structure of the GO and we achieved a scalable and precisely controlled synthesis of sub-nanosized Pt on reduced GO by photocatalytic deposition [3]. References 1. E. Quesnel, F. Roux, F. Emieux, P. Faucherand, E. Kymakis, G. Volonakis, F. Giustino, B. Martín-García, I. Moreels, S. Alkan Gürsel, et al., ‘Graphene-based technologies for energy applications, challenges and perspectives’ 2D Mater., 2, 030204 (2015). 2. B.Y. Kaplan, N. Haghmoradi, E. Biçer, C. Merino, S. Alkan Gürsel, ‘High performance electrocatalysts supported on graphene based hybrids for polymer electrolyte membrane fuel cells’ Int. J. Hydr. Energy, 43, 23221(2018). 3. S. Abdolhosseinzadeh, S. Sadighikia, S. Alkan Gürsel, ‘Scalable synthesis of sub-nanosized platinum-reduced graphene oxide composite by an ultra-precise photocatalytic method’ ACS Sustainable Chem. Eng. 6, 3773 (2018).