| AVS 65th International Symposium & Exhibition | |
| 2D Materials Focus Topic | Friday Sessions |
| Session 2D+EM+MN+NS-FrM |
| Session: | Nanostructures including Heterostructures and Patterning of 2D Materials |
| Presenter: | Reynaldo Geronia, University of the Philippines Diliman |
| Authors: | M. Geronia, University of the Philippines Diliman A.A.B. Padama, University of the Philippines Los Baños, Philippines J.D. Ocon, University of the Philippines Diliman, Philippines P.-Y. A. Chuang, University of California, Merced |
| Correspondent: | Click to Email |
Oxygen reduction reaction (ORR) usually depends on precious metal-based catalysts like platinum and its alloys to facilitate its sluggish kinetics. The high cost of these materials however limits the employment of ORR-based technologies in commercial applications like fuel cells and metal-air batteries. Interestingly, recent works have demonstrated that doped metal-free carbon catalysts, such as graphene-based materials, can facilitate adsorption of ORR intermediate species [1]. This motivates us to investigate the interaction of oxygen atom and oxygen molecule on halogenated graphene systems.
In this work, we performed density functional theory (DFT) based calculations to investigate the stability of coplanar and non-coplanar halogen (X = F, Cl, Br, I) doped monovacant graphene systems. The stability of halogenated-graphene is strongly influenced by the size of halogen dopant as well as the geometry of the vacancy [2]. The calculated adsorption properties of atomic [3] and molecular oxygen on halogenated graphene systems, on the other hand, signifies the possibility of O2 dissociation. We note that the dissociation of the molecule results to the distortion of the geometric structure of the substrate. This leads mostly to the formation of dangling and bridging C-O bonds along the edge of the graphene monovacancy which could have facilitated the dissociation of the molecule. Depending on the halogen, adsorption of oxygen can strengthen or weaken existing C-X bonds, due to differences between the abilities of oxygen and halogens to induce charge transfer and to participate in π bonding with carbon. These findings are expected to increase our understanding of novel graphene-based materials, which are currently being developed with the aim of reducing the use of noble metals as catalysts in fuel cells.
References:
[1] D. Chanda, A.S. Dobrota, J. Hnát, Z. Sofer, I.A. Pašti, N.V. Skorodumova, et al. Int. J. Hydrogen Energy 43 (2018) 12129-12139; L. Yu, X. Pan, X. Cao, P. Hu, X. Bao, J. Catal. 282 (2011) 183-190.
[2] R.M. Geronia, A.C. Serraon, A.A.B. Padama, J.D. Ocon, ECS Trans. 77 (2017) 607-620.
[3] R.M. Geronia, A.A.B. Padama, P.A. Chuang, M.N. Chong, J.D. Ocon, Int. J. Hydrogen Energy (2018), accepted.