Exploring Active Sites in Multi‐Heteroatom‐Doped Co‐Based Catalysts for Hydrogen Evolution Reactions. Issue 48 (25th July 2018) - Shahraei, Ali
Abstract: Today, metal–N‐ as well as metal–S‐doped carbon materials are known to catalyze the hydrogen evolution reaction (HER). However, especially N‐ and S‐co‐doped catalysts reach highest activity, but it remains unclear if the activity is related to MN x or MS y (M=metal) sites. In this work we apply a simple method for multi‐heteroatom doping and investigate the effect of cobalt content on the HER in acidic medium. The CoN x and CoS y sites were evidenced on the basis of structural characterization by Raman, X‐ray induced photoelectron spectroscopy, and TEM. The presence of sulfur enables the formation of a larger number of CoN x sites. Structure–performance relationship proves that the HER activity is dominated by CoN x rather than CoS y sites. The most active catalysts also exhibit an excellent stability under galvanostatic conditions making them of interest for electrolyser application. Abstract : The use of PANIevap as nitrogen, carbon, sulfur and oxygen precursor enables a simple route for the preparation of multi‐heteroatom‐doped Co‐based catalysts. The presence of sulfur enables the formation of larger quantities of CoNx moieties. Based on structure activity correlation it is shown that these CoNx moieties dominate the hydrogen evolution reaction active while cobalt sulfides or cobalt nanoparticles contribute only minor.