Isostructural M 2pt (M = Al, Ga, In, Sn) As OER Anode Materials

Abstract

Looking for the future energy infrastructure, hydrogen will play an important role as energy carrier molecule. Among different physical and chemical methods of hydrogen production, water electrolysis has numerous advantages. However, the sluggish kinetics of anodic oxygen evolution reaction (OER) hinders its large-scale implementation. The intensive search for new OER electrocatalytic materials is limited by harsh oxidative conditions and instability/ changes of electrocatalyst under reaction conditions. Platinum is characterized by pronounced stability against dissolution compared to other noble metals. However, the OER activity of Pt is one of the lowest one. Combining the platinum with main group elements in form of M 2Pt intermetallic compound will lead to the different electronic state of Pt and, correspondingly, different OER activity.The compounds M2 Pt (M = Al, Ga, In, Sn) crystallize with cubic anti-CaF2 type of crystal structure [1]. Due to the pronounced charge transfer from M to Pt, Pt atoms are negatively charged in these compounds. There is only one type of strongly polar covalent interactions between M and Pt atoms. The OER activity decreases in the following sequence In2Pt > Ga2Pt > Al2Pt. This trend is governed by the chemical nature of the counterpart elements M (M = Al, Ga, In) and their leaching rates under OER conditions. The leaching of M into the electrolyte leads to formation of composite material of intermetallic M2 Pt and Pt-rich phase in the near-surface region. The inactivity of Sn2Pt is due to the formation of passivating SnO2 layer with poor electrical conductivity.The study of OER activity of M 2Pt materials under different electrochemical treatments was combined with surface- and bulk characterization of electrodes after electrochemical experiments, elemental analysis of electrolyte and quantum chemical calculations. This allows to investigate the influence of chemical nature of counterpart element M onto the OER performance of isostructural M 2Pt electrode materials [2].[1]. Antonyshyn, I., Barrios Jiménez, A.M., Sichevych, O., Burkhardt, U., Veremchuk, I., Schmidt, M., Ormeci, A., Spanos, I., Tarasov, A., Teschner, D., Algara-Siller, G., Schlögl, R., Grin, Yu. // Angew. Chem. Int. Ed. 59, 16770–16776 (2020).[2]. Barrios Jiménez, A.M., Burkhardt, U., Altendorf, S.G., Kaiser, F., Veremchuk, I., Ormeci, A., Auffermann, G., Antonyshyn, I., Grin, Yu., submitted.