Abstract Achieving ampere-level CO2 electroreduction to multicarbon (C2+) products requires resolving the system-level mass-transport bottleneck inherent to conventional carbon-based gas-diffusion electrodes (GDEs)—namely, a sub-100 nm microporous layer (MPL) and electrowetting-induced flooding under alkaline, high-current-density conditions. Guided by mass-transport simulation, we design a composite GDE comprising a Nafion-coated Cu nanowire (NW) network catalyst layer (CL) and a hydrophobic, MPL-free polytetrafluoroethylene (PTFE) gas-diffusion layer (GDL). The macroporous Cu NW network is intrinsically conductive and enables independent optimization of GDL pore size and CL thickness within a coupled mass-transport architecture. The optimized configuration delivers a Faradaic efficiency of 88.1% and a partial current density of –1.19 A cm–2 for C2+ products while still retaining 71.9% C2+ selectivity with a dilute CO2 feed (15%). Advanced operando spectroscopy characterization reveals that accelerated CO2 flux elevates *CO surface coverage, lowering the C–C coupling onset by ∼60 mV. This work offers important insights into the role of mass transport in industry-relevant CO2-to-C2+ conversion.

As categories of promising semiconductor photocatalysts, the bismuth-based semiconductors still have some defects for influencing their extensive application in the photodegradation of refractory pollutants, such as limited light response capability, slow charge transport rate and severe carrier recombination probability. In this work, a novel BiOBr/CeMo8O14/r-GO (BCG) S-scheme heterojunction was synthesized via a continuous hydrothermal method and employed as a photocatalyst to activate peroxymonosulfate (PMS) for the photodegradation of levofloxacin (LFX). The photodegradation efficiency of LFX by the optimal BCG reaches up to 91.8%, which is approximately twice that of pure BiOBr (merely 46.4%). This can mainly be ascribed to the formation of the S-scheme heterojunction between BiOBr and CeMo8O14, finally promoting the transfer of photogenerated charges, prolonging the carrier lifetime, and offering abundant reactive sites for the activation of PMS. Furthermore, the r-GO serves as an additional electron transfer pathway for effectively accelerating the charge transfer rate within BCG. The free radical capture experiment and electron spin resonance (ESR) measurement verify that ·O2− and 1O2 are the main reactive oxygen species (ROS) for governing the photodegradation process. Density functional theory (DFT) calculation and Kelvin probe force microscopy (KPFM) measurement were performed to elucidate the charge transfer process in BCG and the existence of internal electric field (IEF) between monomers, finally verifying the successful construction of S-scheme heterojunction. Consequently, this research offers an effective approach for the rational fabrication of bismuth-based S-scheme heterojunction photocatalysts featuring efficient photocatalytic performance.

Cobalt disulfide (CoS2) features highly active catalytic sites and is regarded as a promising candidate for electrocatalytic hydrogen evolution. In this study, molybdenum-doped cobalt disulfide (CoS2:Mo) was synthesized via a facile hydrothermal approach. XRD analysis confirms that the obtained samples crystallize in a cubic pyrite structure, with diffraction peaks consistently shifting towards lower angles. SEM characterization reveals that the samples exhibit microrod-like morphologies with an average size of approximately 1 μm. Integrated analyses from XRD, XPS, and EDS mapping demonstrate that Mo is uniformly distributed across the surface and successfully doped into the CoS2 lattice. Electrochemical measurements indicate that the CoS2:Mo sample delivers a low overpotential of 122 mV and a Tafel slope of 128 mV dec−1 at a current density of 10 mA cm−2 in alkaline media, significantly surpassing the performance of pure CoS2 and MoS2. Moreover, the CoS2:Mo exhibits an enhanced double-layer capacitance, with a Cdl value of 2.72 mF cm−2, superior to that of pure CoS2 (1.63 mF cm−2) and MoS2 (0.31 mF cm−2). Mo doping enhances conductivity and active sites, thereby boosting electrocatalysis. This work presents an effective strategy for the development of cost-efficient and high-performance non-precious metal electrocatalysts.

Anion exchange membrane water electrolysis (AEMWE) is a promising technology for large-scale green hydrogen production, but its commercialization is still hindered by the lack of earth-abundant anode catalysts that combine high activity with long-term durability at industry-relevant high current densities. Herein, we report a Cu-MOF-feed-ratio-regulated strategy to construct a trace-Cu-containing FeCoNiCr-based layered double hydroxide, denoted as Cu-FeCoNiCr LDH, for efficient and durable alkaline oxygen evolution reaction (OER) and AEMWE operation. Systematic phase-evolution studies show that catalyst formation is governed by the competition between Cu-rich multimetallic oxide-like phases and Fe/Co/Ni/Cr hydroxide-derived LDH-type phases, rather than by the formation of a single-phase high-entropy oxide. Decreasing the Cu-MOF feed ratio shifts the synthesis toward an LDH-dominated structure, in which Fe, Co, Ni, and Cr constitute the major LDH framework while residual trace Cu acts as an electronic modulator. The optimized Cu-FeCoNiCr LDH catalyst requires an overpotential of only 236.2 mV to reach 10 mA cm−2 and sustaining alkaline OER catalysis at a high current density of 500 mA cm−2 for over 1000 h. Post-OER characterization indicates partial preservation of the nanosheet morphology and LDH/oxyhydroxide-related structural features under high-current-density operation, accompanied by selective compositional evolution and Cr leaching. Density functional theory calculations based on idealized representative activated LDH/oxyhydroxide-like models suggest that trace Cu modulates the electronic structure and OER intermediate adsorption of neighboring Ni-centered motifs. When employed as the anode catalyst in an AEMWE single cell, Cu-FeCoNiCr LDH delivers 1 A cm−2 at 1.733 V and maintains long-term operation for over 1000 h. This work provides a phase-regulation strategy for designing robust multimetallic LDH anodes for practical AEMWE applications.

The development of low-cost and highly active non-noble metal based bifunctional electrocatalysts for overall water splitting is quite crucial for advancing the effective utilization of hydrogen energy. Herein, on the basis of CeF3 monomer, a novel bifunctional electrocatalyst (Mn(BTC),Se-CeF3) with a nanosheet core-shell structure was successfully synthesized through Mn doping from the Mn-BTC deconstruction induced by strong F– coordination under hydrothermal conditions and Se doping during high-temperature annealing. The developed Mn(BTC),Se-CeF3 displays excellent electrocatalytic activities for oxygen evolution reaction and hydrogen evolution reaction (OER and HER) in alkaline conditions, delivering an overpotential of 259 and 98 mV for achieving a current density of 10 mA/cm2, respectively. Collectively, the Mn(BTC),Se-CeF3 based electrolytic cell confirms a superior overall water splitting performance, merely requiring an applied potential of 1.553 V for attaining a current density of 10 mA/cm2. Apart from this, it demonstrates remarkable stability during continuous electrolysis for over 100 h. Density functional theory (DFT) calculations reveal that Mn and Se co-doping effectively activates the Ce sites in CeF3, synergistically enhancing both HER and OER activities. Mn incorporation triggers electron redistribution around Ce sites and Se then synergizes with Mn to fine-tune the electron density of Ce, finally enhancing the HER and OER activity of CeF3 and lowering the electrochemical energy barrier in rate-determining steps (RDS). This work not only proposes a novel strategy but also provides valuable insights for designing high-performance rare earth metals-based bifunctional water-splitting electrocatalysts.

Ru-based catalysts are recognized as one of the most competitive candidates for hydrogen evolution reaction (HER). Nonetheless, reducing Ru loading and maximizing atomic utilization remain paramount priorities for achieving optimal cost efficiency. Herein, the ultrafine Ru nanoparticles loaded on a reduced graphene oxideLa2O3 binary support (Ru/La2O3-rGO) was rationally designed via a simple liquid impregnation method with a low-content Ru of 6.1 wt%. Benefitting from the synergistic interplay of the binary substrate, Ru/La2O3-rGO achieves a current density of 10 mA cm- 2 at an ultrasmall overpotential of 15.8 mV for alkaline HER, outperforming Pt/C, while also exhibiting good stability and high intrinsic activity. This work offers novel insights into the rational design of high-performance, stable, and cost-effective Ru-based HER catalysts.

Herein, a novel Z-scheme BiOBr/BiOF heterojunction was synthesized via one-step microwave-assisted hydrothermal method, which was integrated with peroxymonosulfate (PMS) to design a sulfate radical (center dot SO4- ) based advanced oxidation processes (AOPs) system through PMS activation (BiOBr/BiOF-PMS) toward Levofloxacin (LFX) photodegradation. In order to achieving an optimal degradation efficiency, the formed BiOBr/BiOF-PMS was systematically investigated and the operational parameters for LFX photodegradation were thoroughly optimized. Thereby, the optimal BiOBr/BiOF exhibits a higher photodegradation efficiency of 89.8 % toward LFX via PMS activation compared to others including PMS alone, BiOBr, BiOF and BiOBr/BiOF with varied ratios. Furthermore, the BiOBr/BiOF has superior stability for multiple cycles and universal applicability for degrading various contaminants. This can mainly be attributed that the formed heterojunction between BiOBr and BiOF and the enhanced concentration of oxygen vacancies (OVs) of BiOBr/BiOF heterojunction, which can synchronously promote the separation and transmission of the photogenerated charges (e- /h+) and thereby lead to more reactive oxygen species (ROS). As well, the expanded optical responsiveness and increased specific surface area of BiOBr/BiOF are also mainly responsible for the improved photodegradation capability. Free radical capture experiments and ESR technique verify that the center dot O2- is the primary ROS and center dot SO4- and center dot OH play subordinative role. The photodegradation pathways of LFX were unraveled based on the identified intermediates with a liquidchromatography-mass (LC-MS) technique. Consequently, this study offers a novel route by developing Bi-based heterojunction photocatalyst to activate PMS for refractory antibiotic photodegradation.

Electrocatalytic CO2 reduction into high-value multicarbon products offers a sustainable approach to closing the anthropogenic carbon cycle and contributing to carbon neutrality, particularly when renewable electricity is used to power the reaction. However, the lack of efficient and durable electrocatalysts with high selectivity for multicarbons severely hinders the practical application of this promising technology. Herein, a nanoporous defective Au1Cu single-atom alloy (De-Au1Cu SAA) catalyst is developed through facile low-temperature thermal reduction in hydrogen and a subsequent dealloying process, which shows high selectivity toward ethylene (C2H4), with a Faradaic efficiency of 52% at the current density of 252 mA cm-2 under a potential of -1.1 V versus reversible hydrogen electrode (RHE). In situ spectroscopy measurements and density functional theory (DFT) calculations reveal that the high C2H4 product selectivity results from the synergistic effect between Au single atoms and defective Cu sites on the surface of catalysts, where Au single atoms promote *CO generation and Cu defects stabilize the key intermediate *OCCO, which altogether enhances C-C coupling kinetics. This work provides important insights into the catalyst design for electrochemical CO2 reduction to multicarbon products.

The development of efficient and durable electrocatalysts for the oxygen evolution reaction (OER) is critical for advancing anion exchange membrane water electrolysis (AEMWE) technology for sustainable hydrogen production. Herein, we report the synthesis of multimetallic NiCrFeMo layered double hydroxides (LDHs) via a facile microwave-assisted hydrothermal approach, engineered as high-performance OER catalysts for AEMWE operating at industrially relevant current densities. Advanced X-ray absorption spectroscopy (XAS) studies demonstrate that the interplay of Ni, Cr, Fe, and Mo tailors the electronic structure and coordination environment. Consequently, the NiCrFeMo LDHs exhibit remarkable OER performance, achieving overpotentials of 236 and 387 mV at 10 and 500 mA cm-2, respectively, in 1.0 M KOH, as well as outstanding durability at 500 mA cm-2 for 1000 hours with negligible degradation. In situ differential electrochemical mass spectroscopy (DEMS) and density functional theory (DFT) analyses reveal that the OER taking place on NiCrFeMo LDHs follows the adsorbate evolution mechanism, with minimal lattice oxygen involvement, contributing to the catalyst's longevity. When integrated into a prototype AEM electrolyzer cell as the anode catalyst, the cell demonstrates a current density of 1 A cm-2 at a relatively low voltage of 1.87 V and operates at 0.5 A cm-2 for 100 hours without decay, highlighting the potential of NiCrFeMo LDHs for practical applications. This work elucidates the synergistic effects of multimetallic compositions in LDHs, offering a strategy for designing cost-effective, high-efficiency OER catalysts to support green hydrogen production on scale.

Converting CO2 into value-added chemicals and fuels through electrochemical CO2 reduction reaction (CO2RR) has been acknowledged as a disruptive technology for chemical industry and an important means to realizing carbon neutrality. However, it remains challenging to achieve high selectivity for C2+ products at a large current density with a low overpotential. Herein, we report a scandium (Sc) single-atom-doped CuO nanosheet (Sc1CuO NS) electrocatalyst for efficient and durable CO2-to-C2+ conversion. The optimal Sc1CuO NS catalyst achieves a maximal C2+ Faradaic efficiency of 73 +/- 1.8 % at 475.2 mA cm(-2) under an ultralow potential of -0.6 V versus the reversible hydrogen electrode (RHE) and maintains stable CO2-to-C2+ conversion at similar to 206 mA cm(-2) with a > 60 % Faradaic efficiency for 47 h without degradation. In-situ spectroscopy measurements combined with density functional theory (DFT) calculations reveal that the electron transfer from Sc to Cu enhances the activation of CO2 to *CO. Moreover, the in-situ electrochemical reduction of CuO generates abundant undercoordinated Cu-0 sites, featuring tensile-strained Sc-(O)-Cu motifs, which serve as active centers that reduce the reaction barrier for CC coupling. This work highlights the importance of rare-earth doping combined with in-situ electrochemical surface reconstruction of CuO as an effective catalyst design strategy to boost CO2-to-C2+ conversion performance.

The ultralow-potential hydrazine oxidation reaction (HzOR) can be integrated with hydrogen evolution reaction (HER) to construct the overall hydrazine splitting (OHzS) system, thus realizing energy-saving hydrogen production. Meanwhile, the real electrocatalytic processes normally involve the constantly changed pH and also need to operate under different pH conditions. Therefore, designing advanced pH-universal electrocatalysts with high compatibility for HER and HzOR is of greatly practical significance. Herein, ultrafine Ir nanoparticles embedding in B, N-codoped carbon (Ir/BNC) were facilely synthesized with one Ir-based complex and boric acid by simple mixing and pyrolysis. To reach the current density of 10 mA cm- 2, the bifunctional Ir/BNC merely demands the low potentials of -4.8/-6.3/-38.5 mV for HER, 7.5/157.8/330.1 mV for HzOR, and 19/236/358 mV for OHzS in the alkaline, neutral and acidic electrolytes, respectively, all greatly outperforming commercial Pt/C and displaying the huge energy-saving advantage for pH-universal hydrogen generation over the conventional water splitting. Underlyingly, the codoping of abundant B and N heteroatoms with different electronic modulation effects can play synergistical roles to Ir active sites, endowing with the pH-universal multifunctionality as well as the boosted intrinsic unit activity. Additionally, the large surface area, rich pores and highly graphitized carbon also collectively ensure the remarkable apparent performance for bifunctional HER and HzOR. This work supplies a promising strategy for exploiting pH-universal HER and HzOR bifunctional electrocatalysts, greatly potential to the practical energy-efficient hydrogen generation.

Hydrogen has been deemed as the ideal energy source and carrier due to its unmatched energy efficiency and sustainability. Nevertheless, there is a pressing need to develop cost-effective materials to replace costly Pt in the hydrogen evolution reaction (HER), and the electrocatalysts with low overpotential and robust stability under various conditions is a particularly significant concern. In this study, a straightforward and effective approach was proposed for the precise synthesis of RuP2 nanoparticles encapsulated in N, P, S-tridoped carbon, which involves utilizing zinc pyrithione, phytic acid and Ru salt as starting materials. The effect of different Ru loadings on the morphology and structures of the composite catalysts was examined carefully. The obtained composites exhibit superior alkaline activity surpassing commercial Pt/C and comparable acidic and neutral activity as well as excellent pH-wide stability. DFT computations reveal the integration of RuP2 with tridoped carbon can tailor the electronic structure of Ru active sites by interfacial electron transfer, thus optimizing the adsorption energy and promoting the HER activity. The benign graphitization of doped carbon and porous structures ensure the smooth charge and mass transfer during HER process. The cost-effective and straightforward synthesis methods presented in this work offer a promising alternative to commercial Pt/C for practical hydrogen-related applications.

•Resolving spatially and identifying chemical atoms in layered GeS material.•GeS nanosheets with a thickness of 2, 3 layers exhibit high optical nonlinearity.•Realizing a passively mode-locked fiber laser based on a GeS saturable absorber.•2D GeS is a promising nonlinear material for mid-infrared waveband applications.

Solar-driven semiconductor photocatalysts are highly appealing in applications of environmental remediation and energy conversion. However, photocatalytic reactions, particularly oxygen evolution reaction (OER), are often constrained by the swift recombination of electron-hole pairs, thereby resulting in low reaction efficiency. Although it is effective to separate charge carriers by constructing heterojunctions to form built-in electric field, the lattice mismatch and inefficient interlayer charge transfer of heterojunctions in the photocatalysts limit their further development. Here, we propose a new strategy by constructing an internal electric field for OER through an individual piezoelectric two-dimensional material. The results indicate that the piezoelectric effect regulates the electronic structure, reduces bandgap, improves light absorption efficiency, and that the displacement of positive and negative charge centers is the key factor in the enhanced OER. This research indicates the feasibility of combining piezoelectric properties of two-dimensional materials with OER (1.19 eV), providing new insights and guidance for applying the piezoelectric effect in the OER and opening up a way to promote efficient separation of charge carriers. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(https://creativecommons.org/licenses/by/4.0/).

Despite of urgent needs for highly stable and efficient electrochemical water-splitting devices, it remains extremely challenging to acquire highly stable oxygen evolution reaction (OER) electrocatalysts under harsh industrial conditions. Here, a successful in situ synthesis of FeCoNiMnCr high-entropy alloy (HEA) and high-entropy oxide (HEO) heterocatalysts via a Cr-induced spontaneous reconstruction strategy is reported, and it is demonstrated that they deliver excellent ultrastable OER electrocatalytic performance with a low overpotential of 320 mV at 500 mA cm-2 and a negligible activity loss after maintaining at 100 mA cm-2 for 240 h. Remarkably, the heterocatalyst holds outstanding long-term stability under harsh industrial condition of 6 m KOH and 85 °C at a current density of as high as 500 mA cm-2 over 500 h. Density functional theory calculations reveal that the formation of the HEA-HEO heterostructure can provide electroactive sites possessing robust valence states to guarantee long-term stable OER process, leading to the enhancement of electroactivity. The findings of such highly stable OER heterocatalysts under industrial conditions offer a new perspective for designing and constructing efficient high-entropy electrocatalysts for practical industrial water splitting.

The fluoroquinolone antibiotics, as a category of emerging refractory organic pollutants, have triggered intensive attention due to their persistent ecotoxicology for aquatic environments. Herein, a novel Ag/Bi2MoO6/ZnO (Ag/BMO/ZnO) heterojunction was prepared using a two-step microwave-assisted hydrothermal method for photocatalytic degradation of levofloxacin (LFX). The optimal Ag/BMO/ZnO delivers higher photocatalytic degradation efficiency toward LFX reaching 86.4 %, which is 3 times and 7 times higher than those of neat Bi2MoO6 and ZnO, respectively. This can mainly be attributed that the existence of heterojunction between Bi2MoO6 and ZnO promotes the transmission of photogenerated charges (e−/h+). Furthermore, the introduction of Ag nanoparticles serves as an electron accelerator pump, which can also effectively accelerate the transport and separation of the photogenerated e−/h+. Both of these indirectly retard the recombination of e−/h+. The radical capture assays demonstrate that 1O2, OH, h+ and O2– are responsible for the the degradation of LFX and the 1O2 is the primary reactive oxygen species (ROS). Moreover, based on the identification of degradation intermediates via the liquid-chromatography-mass spectrometry (LC-MS) technique, the possible degradation routes of LFX were plausibly inferred. In conclusion, this work provides a new perspective toward antibiotics removal by developing novel heterojunction photocatalysts anchored with precious nanoparticles.

The fluoroquinolone antibiotics, as a category of emerging refractory organic pollutants, have triggered intensive attention due to their persistent ecotoxicology for aquatic environments. Herein, a novel Ag/Bi2MoO6/ZnO 2 MoO 6 /ZnO (Ag/ BMO/ZnO) heterojunction was prepared using a two-step microwave-assisted hydrothermal method for photo- catalytic degradation of levofloxacin (LFX). The optimal Ag/BMO/ZnO delivers higher photocatalytic degradation efficiency toward LFX reaching 86.4 %, which is 3 times and 7 times higher than those of neat Bi2MoO6 2 MoO 6 and ZnO, respectively. This can mainly be attributed that the existence of heterojunction between Bi2MoO6 2 MoO 6 and ZnO promotes the transmission of photogenerated charges (e_/h+). _ /h + ). Furthermore, the introduction of Ag nanoparticles serves as an electron accelerator pump, which can also effectively accelerate the transport and separation of the photogenerated e_/h+. _ /h + . Both of these indirectly retard the recombination of e_/h+. _ /h + . The radical capture assays demonstrate that 1 O 2 , center dot OH, h+ + and center dot O 2 - are responsible for the the degradation of LFX and the 1 O 2 is the primary reactive oxygen species (ROS). Moreover, based on the identification of degradation intermediates via the liquid- chromatography-mass spectrometry (LC-MS) technique, the possible degradation routes of LFX were plausibly inferred. In conclusion, this work provides a new perspective toward antibiotics removal by developing novel heterojunction photocatalysts anchored with precious nanoparticles.

Pt-based materials are the benchmarked catalysts in the cathodic hydrogen evolution reaction (HER) of water splitting; the prohibitive cost and scarcity of Pt immensely impede the commercialization of hydrogen energy. Ru has aroused significant concern because of its Pt-like activity and much lower price. However, it’s still a top priority to minimize the Ru loading and pursue the most superior cost performance. Herein, N-rich covalent organic framework (COF) was employed to assist the preparation of ultrafine Ru, including nanoclusters and single atoms loaded onto porous N-doped carbon by a simple impregnation-pyrolysis process with a low Ru content of 6.60 wt

The development and exploration of electrocatalysts with the high reactive and abundant availability is still extremely crucial in electrocatalytic overall water splitting. Herein, a novel globular-flowers-like MnO2/ 2 / Co3(PO4)2 3 (PO 4 ) 2 (denoted as MnCoPi) electrocatalyst on nickel foam was successfully prepared through a simple onestep electrodeposition method. The MnCoPi electrocatalyst simultaneously delivers remarkable electrocatalytic activities for hydrogen evolution reaction (HER) with overpotentials (ti10) 10 ) reaching 102 mV and oxygen evolution reaction (OER) with overpotentials (ti10) 10 ) up to 225 mV in 1 M KOH solution. Furthermore, the assembled electrolyzer cell utilizing MnCoPi as the cathode and anode only requires a low voltage of 1.55 V to achieve a current density of 10 mA cm- 2 . Moreover, the developed MnCoPi electrocatalyst shows excellent stability during continuous operation for 48 h in OER, HER and overall water splitting process. Compared with the pristine MnO2, 2 , the significant electrocatalytic properties of MnCoPi can mainly be attributed to the improved physicochemical properties such as distinctive globular-flowers-like morphology, huge specific surface areas and abundant porosity structure, low electrochemical resistance, especially for the formed heterojunction between MnO2 2 and Co3(PO4)2, 3 (PO 4 ) 2 , which can provide abundant reactive sites and accelerated electron transfer, etc. Consequently, this work provides a new avenue for the development of efficient and stable bifunctional electrocatalysts for overall water splitting.

Seawater electrolysis (SWE) represents a promising approach to green hydrogen (H2) production but currently faces substantial challenges such as the interference of chlorine chemistry and high energy consumption. In this work, we demonstrate that by replacing the energy-demanding oxygen evolution reaction (OER) with the sulfion oxidation reaction (SOR) and by implementing the concept of bipolar membrane (BPM) electrolysis in an acidbase dual electrolyte system, not only can the notorious chlorine evolution reaction (CER) be completely circumvented, but the energy consumption of SWE be significantly reduced. To do so, we develop a sulfur and phosphorus co-doped FeCoNiCrMn high entropy alloy (HEA-SP) catalyst, which shows good electrocatalytic performance for the SOR in alkaline-saline water. This can be attributed to the abundant lattice defects and strains in HEA-SP, leading to a high density of active sites and an optimized electronic structure favorable for the SOR. Moreover, density functional theory calculations and in situ Raman spectroscopy characterization reveal the crucial role of imperfect sulfur coverage on the HEA in facilitating the formation of Sx clusters during the SOR. Using the HEA-SP as anode catalysts, the SOR-assisted SWE only needs electrical energy of 0.253 kWh to produce one cubic meter of H2 at 100 mA cm-2, in the presence of a BPM. Impressively, chlorine-free H2 production from seawater and upgrading of sulfions to valuable sulfur can occur simultaneously and spontaneously at 10 mA cm-2, highlighting the great potential of the HEA-SP catalysts and the asymmetric cell design to enable energyand cost-effective seawater electrolysis.