In silico discovery of new dopants for Fe-doped Ni oxyhydroxide (Ni_(1-x)Fe_xOOH) catalysts for oxygen evolution reaction

The oxygen evolution reaction (OER) is critical to efficient water splitting to produce the H_2 fuel for sustainable energy production. Currently, the best non-noble metal OER electrocatalyst in base conditions is the Fe-doped NiOOH (Ni_(1–x)Fe_xOOH), with an overpotential of η = 0.4, but much lower values are desired. We use density functional theory to determine the overall mechanism for the OER of Ni_(1–x)Fe_xOOH, concluding that promoting radical character on the metal–oxo bond is critical to efficient OER. Then we consider replacing Fe with 17 other transition metals of the Fe, Ru, and Os rows, where we find 3 new promising candidates: Co, Rh, and Ir, which we estimate to have η = 0.27, 0.15, and 0.02, respectively, all very much improved performance compared to Fe, making all three systems excellent candidates for experimental testing.