Mn-doped nickel-copper phosphides as oxygen evolution reaction electrocatalyst in alkaline seawater solution.

Compared with traditional water electrolysis, electrolysis of seawater has larger resources and a brighter future. However, seawater contains more elements that have greater corrosive effects on electrodes; especially chloride ions (seawater contains more chloride ions) have the greatest impact. The existence of the corrosion problem creates greater difficulties in electrolyzing seawater, further limiting the efficiency of the electrocatalyst for electrolysis of seawater. In this paper, we report a Mn-doped Ni 2 P/Cu 3 P as an environmentally friendly monofunctional electrode for seawater electrolysis, which was made by a simple hydrothermal phosphatization operation method. The experimental results show that Mn-doped Ni 2 P/Cu 3 P presents overpotential of only 161 mV for oxygen evolution reaction (OER) at iR compensation of 90 and a current density of 10 mA cm−2. It has a small Tafel slope (25.15 mV dec−1) and a large capacitance (9.58 mF cm−2 on 1 × 1 nickel foam), which exceeds most reported oxygen evolution activities of non-precious metal-based electrocatalysts for electrolysis of alkaline seawater. The performance of Ni 2 P/Cu 3 P was probably significantly enhanced due to Mn doping by some characterization means. Through Density functional theory (DFT) analysis, it is known that the doping of Mn gives a large enhancement in the adsorption energy of water when Ni 2 P/Cu 3 P is electrolyzed with seawater. This paper provides train of thought for the exploration of excellent electrocatalysts for electrolysis of alkaline seawater. The experimental results show that Mn-dopedNi 2 P/Cu 3 P present overpotential of only 161 mV at i-R compensation of 90 for oxygen evolution reaction in alkaline seawater. [Display omitted] • Mn-doped Ni 2 P/Cu 3 P electrodes was synthesized for the first time through hydrothermal processes. • The overpotential of Mn-doped Ni 2 P/Cu 3 P electrode is only 161 mV at 10 mA cm−2 for OER. • The doping of Mn gives a large enhancement in the adsorption energy of water. [ABSTRACT FROM AUTHOR]