Electronic regulation of Ce,F-Ni2P/CoP catalyst for efficient water splitting

• Efficient Ce,F-Ni 2 P/CoP catalyst with f-p-d orbital gradient coupling is fabricated. • Work function of the catalyst is significantly reduced by orbital gradient coupling. • The catalyst reveals outstanding full-pH HER and alkaline OER activities. Designing efficient non-precious-metal bifunctional electrocatalysts is still challenging at present. Herein, the efficient Ce,F-Ni 2 P/CoP electrocatalyst for water splitting was successfully fabricated. As shown from the present investigation, the codoping of Ce and F in Ni 2 P/CoP induced the f-p-d gradient orbital coupling in the Ce-F-metal structural unit of the catalyst, significantly reducing the work function of the catalyst, which accelerated the reaction kinetics and improved the intrinsic catalytic activity. The catalyst exhibited the outstanding hydrogen evolution reaction (HER) activity in the full pH range and, especially in alkaline electrolyte, an ultra-low oxygen evolution reaction (OER) overpotential of 243 mV at 50 mA·cm −2 and an excellent HER overpotential of 88 mV at 10 mA·cm −2 were achieved. Moreover, Ce,F-Ni 2 P/CoP displayed an excellent overall water splitting (OWS) performance with η 10 = 1.52 V. DFT theoretical calculations also showed that the gradient orbital coupling resulted in the reduction of the work function of the catalyst. Our work provides a new understanding of designing and constructing high-performance catalysts.