NiCo-LDH@NiCoP composite as bifunctional catalyst exhibiting excellent full water splitting performance

Transition metal phosphides, owing to their hydrogenase-like structure, are theoretically expected to exhibit excellent electrocatalytic performance. However, in practice, their performance often falls short due to the phosphorus loss and the insufficient active sites in the electrochemical processes. In this study, the NiCo-LDH nanosheet coating was applied to the NiCoP nanorod array, which not only prevented the loss of phosphorus during electrochemical processes but also provided abundant active sites, thereby significantly enhancing its electrocatalytic performance. Specially The phosphorus mass loss in NiCoP was 8.3% during the electrochemical processes, whereas in the NiCo-LDH@NiCoP composite, it dropped to 1.12%.The as-prepared NiCo-LDH@NiCoP/NF composite exhibited excellent catalytic activity for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). At 10 mA cm −2 in 1.0 M KOH, its HER overpotentials was only 59 mV, very close to that of Pt/C (58 mV). However, when the current density exceeded 192 mA cm −2 , the HER performance of the NiCo-LDH@NiCoP/NF surpassed that of Pt/C catalyst, with the HER overpotentials being to 233 mV at 200 mA cm −2 and 260 mV at 300 mA cm −2 , significantly lower than those of the Pt/C catalyst (236 mV@200 mA cm −2 and 295 mV @ 300 mA cm −2 ). It also demonstrated excellent OER capability 1.0 M KOH, with an OER overpotential of merely 190 mV at 10 mA cm −2 , much lower than that of RuO 2 catalyst (260 mV). Consequently, the electrolytic cell structured with the bifunctional electrodes (NiCo-LDH@NiCoP/NF||NiCo-LDH@NiCoP/NF) required only 1.4 V@10 mA cm −2 in 1.0 M KOH for full water electrolysis, significantly outperforming that of the cell using full noble metal cell (1.51 V for Pt/C||RuO 2 ).