Phosphorus and Aluminum Codoped Porous NiO Nanosheets as Highly Efficient Electrocatalysts for Overall Water Splitting

We present a facile way to fabricate phosphorus and aluminum codoped nickel oxide-based nanosheets by using layered double hydroxide (AlNi-LDH) as precursors, which showed an overall water-splitting performance in alkaline solution. The codoping of phosphorus and aluminum into nickel oxide nanosheets leads to an optimum balance among surface chemical state, electrochemically active surface area, and density of active sites. As a result, it can afford a current density of 100 mA cm–2 at the overpotential of 310 mV for oxygen evolution reaction (OER) and a current density of 10 mA cm–2 at the overpotential of 138 mV for hydrogen evolution reaction (HER) in 1 M KOH. When it was used as a bifunctional catalyst in a two-electrode water-splitting device, a potential of 1.56 V was achieved at the current density of 10 mA cm–2