Rhodium is usually considered an extremely pricy metal, but its price is currently below that of iridium . As demonstrated, to significantly contribute to the catalysis of hydrogen and oxygen electrode reactions , further investigation of Rh-containing electrocatalysts is needed. In particular, the catalysts where only the surface layer is modified with small amounts of Rh could be especially attractive due to a low penalty in terms of the catalyst price. In our previous work, we have shown that Ni can be modified by small amounts of Rh by galvanic displacement according to the reaction 3Ni(s) + 2Rh 3+ = 3Ni 2+ + 2Rh(s) . When this reaction is performed in a highly acidic and concentrated Rh salt solution, it takes under one minute to significantly boost the HER activity of flat nickel surfaces and several minutes to improve the activity of nickel foam and electrodeposited nickel layers. The same approach works for polycrystalline cobalt electrodes and, besides HER, significantly improves OER .