Urchin-like CoP with Controlled Manganese Doping toward Efficient Hydrogen Evolution Reaction in Both Acid and Alkaline Solution

Splitting water to produce hydrogen through an efficient and low-cost way requires the development of catalysts based on earth-abundant elements. Using d-band theory to modify the band structure, we verified Mn atoms to be potent dopants to greatly reinforce the activity of urchin-like CoP, and this catalyst could reach a current density of 10 mA/cm2 with overpotentials of only 65 and 100 mV in acid and alkaline, which were much superior to that of pristine CoP and close to that of Pt/C catalyst. Also, the outperformance of its durability was tested for 20 h to maintain a current density of 10 mA/cm2. The increments of overpotentials were 2.4 and 1.1 mV in acid and alkaline, respectively. After introducing partial Mn atoms, the density functional theory calculation revealed that the Gibbs free energies of hydrogen adsorption (ΔGads,H) of Mn-doped CoP (−0.07 eV) was much smaller than pristine CoP (−0.157 eV). Furthermore, density of state analysis indicated that the strong interaction between Co atoms and Mn atoms lead the d-band of Co atom to a negative shift, which weakens the forceful adsorption between the hydrogen and Mn-doped CoP and expedited the release of produced hydrogen efficiently.