| AVS 62nd International Symposium & Exhibition | |
| Surface Science | Wednesday Sessions |
| Session SS-WeM |
| Session: | Environmental Interfaces, Ambient Surfaces, In-Operando Studies and Adsorption on 2D Materials |
| Presenter: | Hirohito Ogasawara, SLAC National Accelerator Laboratory |
| Authors: | H. Ogasawara, SLAC National Accelerator Laboratory S. Kaya, SLAC National Accelerator Laboratory H.S. Sanchez Casalongue, SLAC National Accelerator Laboratory M.L. Ng, SLAC National Accelerator Laboratory D. Friebel, SLAC National Accelerator Laboratory A. Nilsson, SLAC National Accelerator Laboratory |
| Correspondent: | Click to Email |
We have been focusing on identifying the surface electronic structure and chemical nature of catalytic electrodes during electrochemical reactions through the use of synchrotron-based ambient pressure photoemission spectroscopy (APXPS) [1]. One of the crucial factors that limit electrochemical water splitting is the large overpotential required for the oxygen evolution reaction. Iridium oxide, which is one of the most widely used anode catalyst, has been shown to have high activity and stability in water electrolysis. APXPS studies indicate both oxide and hydroxide species on the catalyst surface. Under electrochemical oxygen evolution conditions, iridium undergoes a change in oxidation state, which takes place predominantly at the surface of the catalyst [2]. Molybdenum sulfides are promising materials in the search for cost-effective cathode catalyst. We tracked the transformation of amorphous MoS3 nanoparticles during electrochemical hydrogen evolution reactions. We observed that surface sites are converted from MoS3 to MoS2 increasing MoS2 edge-like sites with high activity [3]. The sluggish kinetics in oxygen reduction reaction is one of the key challenges in polymer electrolyte membrane fuel cells. We established that the species on the platinum catalytic electrode change drastically depending on the oxygen pressures. We used this knowledge to clarify that the reaction pathway is dependent on the operating conditions [4].
References[1] S. Kaya, H. Ogasawara, L.-Å. Näslund, J.-O. Forsell, H. Sanchez Casalongue, D.J. Miller, A. Nilsson, Catalysis Today205 (2013) 101
[2] H. Sanchez Casalongue, M.L. Ng, S. Kaya, D. Friebel, H. Ogasawara, A. Nilsson, Angewandte Chemie 126 (2014) 7297
[3] H. Sanchez Casalongue, J.D. Benck, C. Tsai, R.K.B. Karlsson, S. Kaya, M.L. Ng, L.G.M. Pettersson, F. Abild-Pedersen, J.K. Nørskov, H. Ogasawara, T.F. Jaramillo, A. Nilsson, J. Phys. Chem. C 118 (2014) 29252
[4] H. Sanchez Casalongue, S. Kaya, V. Viswanathan, D.J. Miller, D. Friebel, H.A. Hansen, J.K. Nørskov, A. Nilsson, H. Ogasawara, Nature Communications 4 (2013) 2817