Tailoring acidic microenvironment for enhanced electrocatalytic hydrogen generation from alkaline seawater
Shengjun Sun, Kai Wang, Xinxin Li, Zixiao Li, Chaoxin Yang, Shiyin Chen, Imran Shaki, Xuping Sun, Bo Tang
Abstract
Alkaline seawater electrolysis for hydrogen production powered by clean energy is increasingly driving the development of a low-carbon economy. However, the limited proton availability in the electrolyte leads to sluggish cathodic reaction kinetics and elevates energy consumption, which hinders its large-scale application. Herein, low Pt loaded NiCo phosphate-coated NiCoP nanoneedle arrays on Ni foam (Pt@NCPi@NCP/NF) using a spontaneous redox strategy is developed for efficient and durable electrocatalytic hydrogen production from alkaline seawater. <em>In situ</em> Raman spectroscopy confirms that a large number of hydrated hydrogen ion intermediates are generated on the surface of Pt@NCPi@NCP/NF during the hydrogen evolution reaction (HER) process, which successfully constructs a localized acidic microenvironment. Concurrently, the surface Pi layer functions as a proton buffer layer, effectively regulating proton supply to enhance the utilization efficiency of active sites. As a result, the catalyst exhibits excellent HER kinetics under alkaline conditions with a Tafel slope of only 39.65 mV·dec<sup>–1</sup> and a low overpotential of 136 mV to reach 1000 mA·cm<sup>–2</sup>.