Pt 1.8 Pd 0.2 CuGa Intermetallic Nanocatalysts with Enhanced Methanol Oxidation Performance for Efficient Hybrid Seawater Electrolysis.

Seawater electrolysis is a potentially cost-effective approach to green hydrogen production, but it currently faces substantial challenges for its high energy consumption and the interference of chlorine evolution reaction (ClER). Replacing the energy-demanding oxygen evolution reaction (OER) with the methanol oxidation reaction (MOR) represents a promising alternative, as the MOR occurs at a significantly low anodic potential, which cannot only reduces the voltage needed for electrolysis but also completely circumvents the ClER. To this end, developing high-performance MOR catalysts is a key. Herein, we report a novel quaternary Pt 1.8 Pd 0.2 CuGa/C intermetallic nanoparticles (i-NPs) catalyst, which shows a high mass activity (11.13 A mg PGM -1 ), a large specific activity (18.13 mA cm PGM -2 ), and outstanding stability toward alkaline MOR. Advanced in-situ surface-enhanced Raman spectroscopy (SERS), online differential mass spectrometry (DEMS) and density functional theory (DFT) calculations reveal that the introduction of atomically distributed Pd in Pt 2 CuGa intermetallic markedly promotes the oxidation of key reaction intermediates by enriching electron concentration around Pt sites, resulting in weak adsorption of carbon-containing intermediates and favorable adsorption of the synergistic OH - groups near Pd sites. Using Pt 1.8 Pd 0.2 CuGa/C i-NPs as anodic catalysts, we demonstrate MOR-assisted seawater electrolysis that continuously operates under 1.23 V for 240 h in simulated seawater and 120 h in natural seawater without notable degradation, showing great potential for energy-saving and cost-competitive hydrogen production from seawater. This article is protected by copyright. All rights reserved.