Room-Temperature Preparation of Cobalt-Based Electrocatalysts through Simple Solution Treatment for Selectively High-Efficiency Hydrogen Evolution Reaction in Alkaline or Acidic Medium

Figure 2

TEM images of (a) the Co-P precursor, (b) Co-Pi/CoP catalyst, and (c) Co_xO_y catalyst. Element mapping images of Co, O, and P in (d) the Co-P precursor, (e) Co-Pi/CoP catalyst, and (f) Co_xO_y catalyst.

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