Metal oxides supported cobalt nanoparticles: Active electrocatalysts for oxygen evolution reaction

• Cobalt NPs impregnated on metal oxides at room temperature by simple reduction. • Obtained catalysts used for oxygen evolution reaction in alkaline medium. • Co/MO 2 (M: Ti, Zr, Ce) display high electrocatalytic performance towards OER. • Effects of changing temperature and [OH − ] on the activity and mechanism were examined. Besides precious metal oxides, non-noble metal oxides are found to be promising materials especially, in the alkaline medium for OER. In this work, Co/MO 2 (M = Ti, Zr, and Ce) catalysts were synthesized without using any harsh steps such as pyrolization, annealing, calcination, and carbonization. Cobalt nanoparticles with ∼2.6 nm particle size were loaded on metal oxides by simple impregnation and reduction method. Considering the low onset and overpotential values, low Tafel slopes, high exchange current densities, high TOF values, as well as high Faradaic efficiency, Co/CeO 2 , Co/ZrO 2 , and Co/TiO 2 nanocatalysts show the remarkable electrocatalytic performance in 1 M KOH for OER. Moreover, no noticeable change in the performance of Co/MO 2 (M = Ti, Zr, and Ce) catalysts were observed after the stability test at 10 mA.cm −2 . This work will also shed light on other studies, in the preparation of inexpensive, earth abundant, and highly active OER electrocatalysts via changing impregnated metals or metal oxides supports.