Seawater electrolysis to produce hydrogen is a critical technology in marine energy projects; however, the severe anode corrosion caused by the highly concentrated chloride is a key issue should be addressed. In this work, we discover that the addition of sulfate in electrolyte can effectively retard the corrosion of chloride ions to the anode. We take nickel foam as the example and observe that the addition of sulfate can greatly improve the corrosion resistance, resulting in prolonged operating stability. Theoretical simulations and in situ experiments both demonstrate that sulfate anions can be preferentially adsorbed on anode surface to form a negative charge layer, which repulses the chloride ions away from the anode by electrostatic repulsion. The repulsive effect of the adsorbed sulfate is also applicable in highly-active catalyst (nickel iron layered double hydroxide) on nickel foam, which shows ca. 5 times stability of that in traditional electrolyte.
The lack of characterizations of the adsorption capability toward intermediates during reactions causes difficulties in determining the structural optimization principle of the catalysts for the 2-electron oxygen reduction reaction (2e − ORR). Here, a Tafel−θ method is proposed to evaluate the surface coverage (θ) of important intermediates (*OOH and *OH) on the material surface and further help optimize the catalyst. With the assistance of Tafel−θ analysis, a Zn nanoparticle incorporated oxygen-doped carbon (Zn NP -O-C) catalyst with high 2e − ORR performance (onset of ∼0.57 V and selectivity of >90.4%) in neutral media was achieved. Both the theoretical calculation and characterization results are consistent with the Tafel−θ deduction, revealing that an appropriate ratio of Zn nanoparticles and bridging O can optimize the *OOH adsorption/desorption strength of the adjacent carbon site. This study not only provides an advanced Zn NP -O-C catalyst for electrochemical H 2 O 2 production but also proposes a fast and precise method for the comprehensive assessment of future catalysts.
Electrochemical hydrogen evolution reaction (HER) with cost‐effectiveness, high performance, and repeatable scale‐up production hold promises for large‐scale green hydrogen generation technology. Herein, a convenient method for scaling up Cu2S@NiS@Ni/NiMo electrocatalysts on Cu foam with high geometric area over 100 cm2 is presented. The hybrid electrode exhibits high hydrogen evolution activity with 190 and 250 mV overpotential at 1000 mA cm−2 and superior stability with negligible overpotential loss after over 2000 h at 500 mA cm−2 under steady‐state conditions in both artificial seawater and real seawater. Detailed characterizations and simulations demonstrate that high intrinsic activity resulting from the unique boundary interface, enhance mass transport resulting from superaerophobic nanoarray architecture, and corrosion resistance resulting from polyanion‐rich passivating layers together lead to the outstanding performance. The practicability is also demonstrated in an alkaline seawater electrolyzer coupling with the hybrid electrode and stable commercial anode.
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