Cost efficient and long-term stable catalysts are in great demand for the oxygen evolution reaction (OER), a key process involved in water splitting cells and metal–air batteries. Here, we demonstrate that the ultrathin amorphous cobalt–vanadium hydr(oxy)oxide we synthesized is a highly promising electrocatalytic material for the OER with a low overpotential of 0.250 V (even lower down to 0.215 V when supported on Au foam) at 10 mA cm−2 and a long stable operation time (170 h) in alkaline media. In combination with in situ X-ray absorption spectral characterization and first-principles simulations, we reveal that the ultrathin, amorphous and alloyed structural characteristics have enabled its facile transformation to the desirable active phase, leading to a dramatically enhanced catalytic activity. Our finding highlights the remarkable advantages of the two-dimensional amorphous material and sheds new light on the design of high-performance electrocatalysts.
