Direct ethanol fuel cells are one of the most promising electrochemical energy conversion devices for portable electronics and electric vehicles. Highly efficient and robust electrocatalysts for the ethanol oxidation reaction are therefore desired. In this paper, we report a facile approach for synthesizing monodisperse PdSn/SnO_x core/shell nanoparticles as high-performance catalysts for electrochemical ethanol oxidation reaction (EOR). The mass current density of PdSn/SnO_x reached 3.2 A mg_Pd ⁻¹ at 0.85 V vs. RHE in 1 M KOH solution, which is 3.2 times higher than that of the commercial Pd catalyst. More importantly, these PdSn/SnO_x core/shell nanoparticles exhibit enhanced stability compared with the commercial Pd catalyst. Density functional theory calculations suggest that the strong d–p orbital coupling and sp-electron transfer in the PdSn alloy weaken the adsorption of carbonaceous species, e.g., the acetate-evolution intermediate *CH₃CO and the poisoning species *CO, at Pd sites. Consequently, the destabilization of these species facilitates their coupling with *OH, leading to enhanced EOR activity and poison resistance. Meanwhile, we found that amorphous SnO_x layers possess rich Sn–Sn ensembles with stronger adsorption of *OH, providing a shuttling path of hydroxide ions to surface sites.

Direct seawater electrolysis has recently emerged as a sustainable approach for green hydrogen production by harnessing abundant marine resources. However, its industrial deployment faces significant challenges due to the complex composition of seawater enriched in diverse ions and microorganisms which can induce severe chemical and physical degradation of electrolysis systems. Despite significant advances in the field, a comprehensive overview and analysis of seawater electrolysis remain relatively limited, particularly regarding electrochemical fundamentals, materials development and technological innovation. In this review, we provide a systematic overview of recent advances in electrocatalytic seawater electrolysis and offer insights into the major barriers to achieving stable hydrogen production. We discuss key aspects such as catalyst and electrode design, electrolyzer optimization, etc., to establish a roadmap for the commercialization of efficient, cost-effective and sustainable seawater electrolysis technology.

Article Wenjin Sun ^1,†, Bokki Min ^2,†, Maoyu Wang ³, Xue Han ⁴, Qiang Gao ¹, Sooyeon Hwang ⁵, Hua Zhou ³, and Huiyuan Zhu ^{1,2,* 1} Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA ² Department of Chemical Engineering, University of Virginia, Charlottesville, VA 22904, USA ³ Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA ⁴ Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA ⁵ Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA * Correspondence: kkx8js@virginia.com † These authors contributed equally to this work. Received: 22 October 2024; Revised: 25 November 2024; Accepted: 27 November 2024; Published: 4 December 2024 Abstract: The electrochemical CO₂ reduction reaction (CO₂RR) has attracted significant attention as a promising strategy for storing intermittent energy in chemical bonds while sustainably producing value-added chemicals and fuels. Copper-based bimetallic catalysts are particularly appealing for CO₂RR due to their unique ability to generate multi-carbon products. While substantial effort has been devoted to developing new catalysts, the evolution of bimetallic systems under operational conditions remains underexplored. In this work, we synthesized a series of Cu_xNi_1−x nanoparticles and investigated their structural evolution during CO₂RR. Due to the higher oxophilicity of Ni compared to Cu, the particles tend to become Ni-enriched at the surface upon air exposure, promoting the competing hydrogen evolution reaction (HER). At negative activation potentials, cathodic corrosion has been observed in Cu_xNi_1−x nanoparticles, leading to the significant Ni loss and the formation of irregularly shaped Cu nanoparticles with increased defects. This structural evolution, driven by cathodic corrosion, shifts the electrolysis from HER toward CO₂ reduction, significantly enhancing the Faradaic efficiency of multi-carbon products (C₂₊).