To further reveal the trend of substances used as electrocatalysts, herein we selected substances whose CAS indexed role is catalyst. Figure shows that the top two substances are carbon and platinum. Carbon based materials are utilized as support to produce non-noble metal electrodes, while platinum based electrodes are used as a benchmark for comparison. Nickel, graphene, cobalt, nitrogen, and iron are also frequently used for electrocatalyst research. Nitrogen is present in N-doped carbon materials which possess active sites for catalytic reactions. Single atom catalysts of transition metals such as iron, copper, and manganese loading on nitrogen doped carbon supports perform efficiently as oxygen reduction reaction catalysts in fuel cells. Cobalt, nickel, copper containing core-shell catalysts made of Co-Ni carbonate hydroxides (CoNiCH) and Cu(OH)2[Cu(OH)2@CoNiCH] was found to be efficient for oxygen evolution reaction. Copper, nickel, and phosphorus composites enable urea electrolysis to produce hydrogen at low overpotentials. Similar to platinum ruthenium dioxide (RuO2) and iridium oxide (IrO2) are used as benchmark for comparison with non-noble metalbased electrocatalysts for oxygen evolution reaction applications.