Seawater electrolysis has attracted considerable attention in hydrogen production. However, the chloride ions (Cl⁻) in seawater can corrode metal sites and decrease the lifespans of the oxygen evolution reaction (OER). Herein, we report a reversed-active sites strategy, converting Cl⁻-affinitive metal sites to Cl⁻-repellent oxygen sites, for OER in alkaline seawater electrolysis. First, ex/in situ experiments confirm the effectiveness of such a strategy using typical perovskites following the adsorbate evolution mechanism (AEM) or lattice oxygen-mediated mechanism (LOM). Furthermore, the origins of the superior activity and durability of as-prepared La_0.3SrCo_0.5Fe_0.5O_x (La0.3) can be ascribed to higher participation of lattice oxygen in OER, rapid bulk oxygen diffusion, and excellent OH⁻ adsorption kinetics. Hence, an alkaline seawater electrolytic cell with La0.3 as the anode produces 10 mA cm⁻² at just 1.57 V and maintains near-constant activity over 150 hours. This work introduces novel concepts for the production of superactive and steady electrocatalysts for the electrolysis of seawater.

Electrochemical water splitting represents one of the most promising technologies to produce green hydrogen, which can help to realize the goal of achieving carbon neutrality. While substantial efforts on a laboratory scale have been made for understanding fundamental catalysis and developing high-performance electrocatalysts for the two half-reactions involved in water electrocatalysis, much less attention has been paid to doing relevant research on a larger scale. For example, few such researches have been done on an industrial scale. Herein, we review the very recent endeavors to bridge the gaps between fundamental research and industrial applications for water electrolysis. We begin by introducing the fundamentals of electrochemical water splitting and then present comparisons of testing protocol, figure of merit, catalyst of interest, and manufacturing cost for laboratory and industry-based water-electrolysis research. Special attention is paid to tracking the surface reconstruction process and identifying real catalytic species under different testing conditions, which highlight the significant distinctions of corresponding electrochemical reconstruction mechanisms. Advances in catalyst designs for industry-relevant water electrolysis are also summarized, which reveal the progress of moving the practical applications forward and accelerating synergies between material science and engineering. Perspectives and challenges of electrocatalyst design strategies are proposed finally to further bridge the gaps between lab-scale research and large-scale electrocatalysis applications.

Solid oxide electrolysis cells (SOECs), displaying high current density and energy efficiency, have been proven to be an effective technique to electrochemically reduce CO₂ into CO. However, the insufficiency of cathode activity and stability is a tricky problem to be addressed for SOECs. Hence, it is urgent to develop suitable cathode materials with excellent catalytic activity and stability for further practical application of SOECs. Herein, a reduced perovskite oxide, Pr_0.35Sr_0.6Fe_0.7Cu_0.2Mo_0.1O_3-δ (PSFCM0.35), is developed as SOECs cathode to electrolyze CO₂. After reduction in 10% H₂/Ar, Cu and Fe nanoparticles are exsolved from the PSFCM0.35 lattice, resulting in a phase transformation from cubic perovskite to Ruddlesden–Popper (RP) perovskite with more oxygen vacancies. The exsolved metal nanoparticles are tightly attached to the perovskite substrate and afford more active sites to accelerate CO₂ adsorption and dissociation on the cathode surface. The significantly strengthened CO₂ adsorption capacity obtained after reduction is demonstrated by in situ Fourier transform-infrared (FT-IR) spectra. Symmetric cells with the reduced PSFCM0.35 (R-PSFCM0.35) electrode exhibit a low polarization resistance of 0.43 Ω cm² at 850 ℃. Single electrolysis cells with the R-PSFCM0.35 cathode display an outstanding current density of 2947 mA cm⁻² at 850 ℃ and 1.6 V. In addition, the catalytic stability of the R-PSFCM0.35 cathode is also proved by operating at 800 ℃ with an applied constant current density of 600 mA cm⁻² for 100 h.

For protonic ceramic fuel cells, it is key to develop material with high intrinsic activity for oxygen activation and bulk proton conductivity enabling water formation at entire electrode surface. However, a higher water content which benefitting for the increasing proton conductivity will not only dilute the oxygen in the gas, but also suppress the O₂ adsorption on the electrode surface. Herein, a new electrode design concept is proposed, that may overcome this dilemma. By introducing a second phase with high-hydrating capability into a conventional cobalt-free perovskite to form a unique nanocomposite electrode, high proton conductivity/concentration can be reached at low water content in atmosphere. In addition, the hydronation creates additional fast proton transport channel along the two-phase interface. As a result, high protonic conductivity is reached, leading to a new breakthrough in performance for proton ceramic fuel cells and electrolysis cells devices among available air electrodes.

One of the critical challenges that limit broad commercialization of proton exchange membrane fuel cells (PEMFC) is to reduce the usage of Pt while maintaining high power output and sufficient durability. Herein, a novel bi-functional layer consisting of vertically aligned carbon nanotubes (VACNTs) and nanoparticles of Pt-Co catalysts (Pt-Co/VACNTs) is reported for high-performance PEMFCs. Readily prepared by a two-step process, the Pt-Co/VACNTs layer with a hydrophilic catalyst-loaded side and a hydrophobic gas diffusion side enables a PTFE-free electrode structure with fully exposed catalyst active sites and superior gas–water diffusion capability. When tested in a PEMFC, the bi-functional Pt-Co/VACNTs layer with ultralow Pt loading (~65 μg_cathode cm⁻²) demonstrates a power density of 19.5 kW g_{Pt cathode}⁻¹ at 0.6 V, more than seven times that of a cell with commercial Pt/C catalyst (2.7 kW g_{Pt cathode}⁻¹ at 0.6 V) at a loading of 400 μg_cathode cm⁻² tested under similar conditions. This remarkable design of VACNTs-based catalyst with dual functionalities enables much lower Pt loading, faster mass transport, and higher electrochemical performance and stability. Further, the preparation procedure can be easily scaled up for low-cost fabrication and commercialization.