Self‐Powered Hydrogen Production From Seawater Enabled by Trifunctional Exfoliated PtTe Nanosheet Catalysts

Seawater electrolysis (SWE) is proposed to be a promising approach to green hydrogen (H2) production but its large‐scale deployment faces challenges because of the anodic competing chlorine evolution reaction (CER) and high energy consumption. To address these challenges, innovative hybrid SWE systems have recently emerged, able to mitigate the interference of CER and substantially reduce the electrical energy needed. Herein, the preparation of 2D layered PtTe nanosheets (e‐PtTe NSs) using the liquid‐phase exfoliation method is reported, which show outstanding electrocatalytic performance for the hydrogen evolution (HER), hydrazine oxidation (HzOR), and oxygen reduction reactions (ORR) in seawater. Using e‐PtTe NSs as trifunctional catalysts, two hybrid SWE systems are demonstrated: 1) a hydrazine‐assisted acid‐alkaline dual‐electrolyte seawater electrolyzer enabled by a bipolar membrane (BPM‐OHzSWE), which can simultaneously produce H2 and generate electricity through harvesting the electrochemical neutralization energy and leveraging the advantage of the HzOR over the oxygen evolution reaction (OER) in terms of anodic potentials; 2) a hydrazine‐assisted SWE system powered by a direct hydrazine fuel cell (DHzFC), which can realize self‐powered H2 production. These novel hybrid SWE systems show substantial promise for energy‐saving and cost‐effective production of H2 from seawater. Exfoliated PtTe nanosheets can serve as trifunctional electrocatalysts showing outstanding performance toward the hydrogen evolution, hydrazine oxidation, and oxygen reduction reactions in alkaline‐saline water, which enable chlorine‐free seawater electrolysis with significantly reduced energy consumption and even self‐powered hydrogen production.