fig4

Figure 4. Classification of Rh-based HER catalysts^{[37,95,100-103]}. Doping is reproduced from Ref.^[100] with permission. Copyright 2022, Wiley. Rh-metallene is reproduced from Ref.^[101] with permission. Copyright 2022, Wiley. Compound is reproduced from Ref.^[103] with permission. Copyright 2023, Wiley. Composite is reproduced from Ref.^[102] with permission. Copyright 2019, American Chemical Society. Alloy is reproduced from Ref.^[95] with permission. Copyright 2024, Springer. Cluster is reproduced from Ref.^[37] with permission. Copyright 2022, Springer.