Vanadium-doped Ni microspheres loaded with phosphatization of NiMoO contributing to enhanced electron transfer for stable overall water splitting.

At present, there are few reports on the micron-sized catalysts for overall water splitting. In this study, phosphating method were used to construct the self-supporting catalyst (V doped Ni microspheres coated by NiMoO/NiP) with microspherical structure, providing a short path and a stable structure to guarantee quick electron transfer and excellent catalytic performance. Hence, oxygen evolution reaction (OER) only needs 254 mV to reach a current density of 50 mA cm in 1.0 mol/L KOH, after 114 h without attenuation. The catalyst can achieve a current densitiy of 10 mA cm with a voltage of only 158 mV for hydrogen evolution reaction (HER). When micron scale V-Ni@NiMoO/NiP is used as both anode and cathode for overall water splitting, the device can operate at a current density of 10 mA cm for more than 200 h of good stability. Its superior catalytic performance can be attributed to the construction of micron size and phosphating. DFT calculations indicate that the introduction of P better activates the adsorbed OH and HO, reduces reaction the energy barrier, and improves the catalytic activity.