Mo–CoP/Yb₂O₃ Heterostructure for Boosted Alkaline Hydrogen Evolution Reaction and Urea/Hydrazine Oxidation-Assisted Processes

The development of highly efficient nonprecious metal electrocatalysts for hydrogen evolution reaction (HER) is important and urgent. Herein, a heterostructured electrocatalyst Mo–CoP/Yb₂O₃ was fabricated between Mo-doped CoP and rare-earth oxide Yb₂O₃. Mo–CoP/Yb₂O₃ not only displays outstanding HER activity but also exhibits outstanding urea oxidation and hydrazine oxidation activity, for which the HER activity is indicated by the low overpotential values of 33 mV at 10 mA cm^–2 and 100 mV at 100 mA cm^–2, the urea oxidation performance with the potential of 1.449 V vs RHE at 100 mA cm^–2, and the hydrazine oxidation performance with the potential of 0.153 V vs RHE at 100 mA cm^–2. Further, when Mo–CoP/Yb₂O₃ was used as both the cathode and anode for urea-assisted hydrogen production (cell voltage of 1.513 V at 100 mA cm^–2) and hydrazine oxidation-assisted hydrogen production (cell voltage of 0.253 V at 100 mA cm^–2), it is economically advantageous. The results show that Mo-doped CoP plays a significant role in the catalytic process, while the incorporation of Yb₂O₃ can enhance the catalyst’s hydrophilicity and increase the water adsorption, potentially aiding in water splitting. Besides, the synergistic effect of Mo doping and heterostructure regulates the electronic structure and facilitates the electron transfer, thus improving the HER activity of Mo–CoP/Yb₂O₃.