O 2(g) + 2H 2 O + 4e -= 4OH - (4) in acidic media. While HER and OER take place in water electrolysis systems, HOR and ORR occur in the fuel cell anode and cathode, respectively. However, proper electrocatalysts are needed in order to proceed with any of these reactions. In acidic media, catalyst corrosion is very prominent; thus, noble metal catalysts are used. On the other hand, in alkaline media, non-noble materials are used because the corrosion is less pronounced. In practice, nickel and nickel-based electrocatalysts are most commonly used in alkaline media . The catalytic activity of pure nickel can be tuned by morphology and the active surface area . Further strategies to improve the catalytic activity of Ni are alloying with noble and non-noble metals, like Mo , Cu , and Co . Additionally, the interfacial effects could enhance H2 production via improved water splitting or the facilitated recombination of adsorbed hydrogen intermediates into H2 .