A Novel Heterostructure Based on RuMo Nanoalloys and N‐doped Carbon as . . . Accordingly, the as-made RuMo-nanoalloys-embedded hexagonal porous carbon nanosheets are promising for the hydrogen evolution reaction (HER), resulting in an extremely small overpotential (18 mV), an ultralow Tafel slope (25 mV dec −1), and a high turnover frequency (3 57 H 2 s −1) in alkaline media, outperforming current Ru-based