Atomically Dispersed Pt catalysts for Enhancing Electrochemical Chlorine Evolution Reaction

Abstract

Electrochemical chlorine evolution reaction (CER, 2 Cl− + 2 e− → Cl2) plays a pivotal role in a chlor-alkali process. The class of metal- and nitrogen-cooped carbon (M–N/C) catalysts comprising atomically dispersed M–Nx sites has been studied for many important electrocatalytic reactions, such as hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). However, to the best of our knowledge, the M–N/C catalysts have never been exploited as an active catalyst for the CER. In this work, we report a platinum- and nitrogen-codoped carbon nanotube (Pt–N/CNT) catalyst with high CER activity in acidic media, which allows for minimizing the usage of expensive Pt. The Pt–N/CNT catalysts exhibited a onset potential (~30 mV) and ca. 6 times higher mass activity for CER than those of Pt nanoparticles supported on CNT (PtNP/CNT) catalyst in 1.0 M NaCl electrolyte (pH ~1). The CER on the Pt–N/CNT catalyst followed the Volmer-Heyrovsky mechanism, as revealed by Tafel analysis. Furthermore, we also found that the activity of the Pt–N/CNT catalysts for the CER was dependent on the heat-treatment temperatures, with the sample treated at 700 ℃ showing the best performances.