Promoting Activity and Selectivity of Electrochemical Chlorine Evolution Reaction by Atomically Dispersed Pt Catalysts

Abstract

MAT.P-300 Promoting Activity and Selectivity of Electrochemical Chlorine Evolution Reaction by Atomically Dispersed Pt Catalysts

Taejung Lim, Gwan Yeong Jung, Sang Kyu Kwak, Sang Hoon Joo*

School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Korea

Area: Material Chemistry Type: Poster Presentation Code: MAT.P-300 Location: Exhibition Hall 1 Date: THU 11:00~12:30

Electrochemical chlorine evolution reaction (CER, 2 Cl−(aq) → Cl2(aq) + 2 e−) plays a pivotal role in both industrial and small-scale Cl2 generation. Mixed metal oxides (MMOs) based on precious metals, such as Ru/Ir-based dimensionally stable anode (DSA), have been predominantly used as CER electrocatalysts. The MMOs are, however, also highly active for oxygen evolution reaction (OER), leading to the energy losses of electrolyzer systems and the degradation of MMO catalysts. Thus, the development of highly active and selective CER catalysts comprising minimal amounts of precious metals offers a pathway to reduce the Cl2 production cost and its energy requirement. In this work, we demonstrate that an atomically dispersed Pt−N4 sites on carbon nanotubes electrocatalyst (Pt1/CNT) exhibits excellent CER performances in terms of overpotential, Tafel slope, turnover frequency, and stability, surpassing that of Pt nanoparticles on CNT catalyst (PtNP/CNT) and a commercial Ru/Ir-based DSA catalyst. Moreover, the CER selectivity of Pt1/CNT was universally higher than that of DSA catalyst in the Cl− concentration as low as 0.1 M and neutral pH. In situ X-ray absorption spectroscopy and density functional theory calculations suggest PtN4C12 site as the most plausible active site structure. This work presents the first example of the atomically dispersed catalyst for the CER and is expected to provide an alternative for MMO catalysts.