Phosphorus doped nickel selenide for full device water splitting

Self-supported P doped NiSe2 and NiSe2 were synthesized through a selenylation process by using nickel foam as precursor. The P doping leads to the increase electrochemical activities for water splitting. [Display omitted] The lack of high active and stable electrocatalysts has impeded the development of electrochemical water splitting device, which is promising technique for renewable energy conversion system. Here, we report a one-step protocol to synthesize P doped NiSe2 (P-NiSe2) by selenylation process derived from nickel foam with assistant of NaH2PO2 and Se powder. The P-NiSe2 could be directly used as working electrode and shows the superior electrochemical activity, offering current density of 10 mA cm−2 with overpotential of 270 mV for OER and 71 mV for HER. The enhanced electrochemical activity can be ascribed to the P atom doping. The P atom doping leads to the high valence state of Ni active sites, which have high catalytic ability towards OER. Moreover, the P doping makes the d-band center of Ni atoms in P-NiSe2 move close to Fermi level, facilitating the HER kinetics with respect to proton adsorption and hydrogen desorption. When employed P-NiSe2 as both anodic and cathodic electrode in alkaline water electrolyzer, a current density of 10 mA cm−2 can be achieved at 1.58 V. Our work highlights the importance of P doping in determining the surface electron configuration for full device water splitting and the facile synthesis protocol would be promising for realistic applications.