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Biogeochemical reactions modulate the chemical composition of the oceans and atmosphere, providing feedbacks that sustain planetary habitability over geological time. Here, we mathematically evaluate a suite of biogeochemical processes to identify combinations of reactions that stabilize atmospheric carbon dioxide by balancing fluxes of chemical species among the ocean, atmosphere, and geosphere. Unlike prior modeling efforts, this approach does not prescribe functional relationships between the rates of biogeochemical processes and environmental conditions. Our agnostic framework generates three types of stable reaction combinations: closed sets, where sources and sinks mutually cancel for all chemical reservoirs; exchange sets, where constant ocean-atmosphere conditions are maintained through the growth or destruction of crustal reservoirs; and open sets, where balance in alkalinity and carbon fluxes is accommodated by changes in other chemical components of seawater or the atmosphere. These three modes of operation have different characteristic timescales and may leave distinct evidence in the rock record. To provide a practical example of this theoretical framework, we applied the model to recast existing hypotheses for Cenozoic climate change based on feedbacks or shared forcing mechanisms. Overall, this work provides a systematic and simplified conceptual framework for understanding the function and evolution of global biogeochemical cycles.
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BACKGROUND: Cyprinidae, the largest fish family, encompasses approximately 367 genera and 3006 species. While they exhibit remarkable adaptability to diverse aquatic environments, it is exceptionally rare to find them in seawater, with the Far Eastern daces being of few exceptions. Therefore, the Far Eastern daces serve as a valuable model for studying the genetic mechanisms underlying seawater adaptation in Cyprinidae. RESULTS: Here, we sequenced the chromosome-level genomes of two Far Eastern daces (Pseudaspius brandtii and P. hakonensis), the two known cyprinid fishes found in seawater, and performed comparative genomic analyses to investigate their genetic mechanism of seawater adaptation. Demographic history reconstruction of the two species reveals that their population dynamics are correlated with the glacial-interglacial cycles and sea level changes. Genomic analyses identified Pseudaspius-specific genetic innovations related to seawater adaptation, including positively selected genes, rapidly evolving genes, and conserved non-coding elements (CNEs). Functional assays of Pseudaspius-specific variants of the prolactin (prl) gene showed enhanced cell adaptation to greater osmolarity. Functional assays of Pseudaspius specific CNEs near atg7 and usp45 genes suggest that they exhibit higher promoter activity and significantly induced at high osmolarity. CONCLUSIONS: Our results reveal the genome-wide evidence for the evolutionary adaptation of cyprinid fishes to seawater, offering valuable insights into the molecular mechanisms supporting the survival of migratory fish in marine environments. These findings are significant as they contribute to our understanding of how cyprinid fishes navigate and thrive in diverse aquatic habitats, providing useful implications for the conservation and management of marine ecosystems.
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Cyprinidae , Ecossistema , Animais , Filogenia , Cyprinidae/genética , Genômica , Água do Mar , Adaptação Fisiológica/genéticaRESUMO
Photosynthesis of H2O2 from seawater represents a promising pathway to acquire H2O2, but it is still restricted by the lack of a highly active photocatalyst. In this work, we propose a convenient strategy of regulating the number of benzene rings to boost the catalytic activity of materials. This is demonstrated by ECUT-COF-31 with adding two benzene rings as the connector, which can result in 1.7-fold enhancement in the H2O2 production rate relative to ECUT-COF-30 with just one benzene ring as the connector. The reason for enhancement is mainly due to the release of *OOH from the surface of catalyst and the final formation of H2O2 being easier in ECUT-COF-31 than in ECUT-COF-30. Moreover, ECUT-COF-31 provides a stable photogeneration of H2O2 for 70 h, and a theoretically remarkable H2O2 production of 58.7 mmol per day from seawater using one gram of photocatalyst, while the cost of the used raw material is as low as 0.24 $/g.
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An interfacial solar steam generation evaporator for seawater desalination has attracted extensive interest in recent years. Nevertheless, challenges still remain in relatively low evaporation rate, unsatisfactory energy conversion efficiency, and salt accumulation. Herein, we have demonstrated a biomimetic bilayer composite aerogel consisting of bottom hydrophilic and vertically aligned EVOH channels and an upper hydrophobic conical Fe3O4 array. Thanks to the design merits, the 3D Fe3O4/V-EVOH evaporator exhibits a high evaporation rate of â¼2.446 kg m-2 h-1 and an impressive solar energy conversion efficiency of â¼165.5% under 1 sun illumination, which is superior to those of state-of-the-art evaporators reported so far. Moreover, the asymmetrical wettability not only allows the evaporator to self-float on the water but also facilitates the salt ion diffusion in the channels; thus, the evaporator shows no salt crystals on its surface and only a 6% decrease in evaporation performance even after the salt concentration increases from 0 to 10.0 wt %.
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Photothermal membrane distillation (PMD) has emerged as a promising and sustainable approach for seawater desalination and wastewater purification. However, the wide application of the technique is severely impeded by low freshwater production and membrane fouling/wetting issues. Herein, we developed an advanced hydrogel-engineered membrane with simultaneously enhanced photothermal conversion capacity and desired fouling and wetting resistance for PMD. By the synergies of photothermal Ti3C2Tx MXene nanosheets and the tannic acid-Fe3+ network in the hydrogel, the membrane was endowed with excellent surface self-heating ability, yielding the highest freshwater production rate (1.71 kg m-2 h-1) and photothermal efficiency among the fabricated hydrogel composite membranes under 1 sun irradiation. Meanwhile, the PMD membrane could robustly resist oil-induced fouling and surfactant-induced wetting, significantly extending the membrane lifespan in treating contaminated saline water. Furthermore, when desalinating real seawater, the membrane exhibited superior durability with a stable vapor flux and excellent ion rejection (e.g., 99.24% for boron) for 100 h.
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A significant challenge in direct seawater electrolysis is the rapid deactivation of the cathode due to the large scaling of Mg(OH)2. Herein, we synthesized a Pt-coated highly disordered NiCu alloy (Pt-NiCu alloy) electrode with superior solidophobic behavior, enabling stable hydrogen generation (100 mA cm-2, >1000 h durability) and simultaneous production of Mg(OH)2 (>99.0% purity) in electrolyte enriched with Mg2+ and Ca2+. The unconventional solidophobic property primarily stems from the high surface energy of the NiCu alloy substrate, which facilitates the adsorption of surface water and thereby compels the bulk formation of Mg(OH)2 via homogeneous nucleation. The discovery of this solidophobic electrode will revolutionarily simplify the existing techniques for seawater electrolysis and increase the economic viability for seawater electrolysis.
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Salinity impacts crop growth and productivity and lowers the activities of rhizosphere microbiota. The identification and utilization of habitat-specific salinity-adapted plant growth-promoting rhizobacteria (PGPR) are considered alternative strategies to improve the growth and yields of crops in salinity-affected coastal agricultural fields. In this study, we characterize strain L1I39T, the first Aquabacter species with PGPR traits isolated from a salt-tolerant pokkali rice cultivated in brackish environments. L1I39T is positive for 1-aminocyclopropane-1-carboxylate deaminase activity and nitrogen fixation and can promote pokkali rice growth by supplying fixed nitrogen under a nitrogen-deficient seawater condition. Importantly, enhanced plant growth and efficient root colonization were evident in L1I39T-inoculated plants grown under 20% seawater but not in zero-seawater conditions, identifying brackish conditions as a key local environmental factor critical for L1I39T-pokkali rice symbiosis. Detailed physiological studies revealed that L1I39T is well-adapted to brackish environments. In-depth genome analysis of L1I39T identified multiple gene systems contributing to its plant-associated lifestyle and brackish adaptations. The 16S rRNA-based metagenomic study identified L1I39T as an important rare PGPR taxon. Based on the polyphasic taxonomy analysis, we established strain L1I39T as a novel Aquabacter species and proposed Aquabacter pokkalii sp nov. Overall, this study provides a better understanding of a marine-adapted PGPR strain L1I39T that may perform a substantial role in host growth and health in nitrogen-poor brackish environments.
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Fixação de Nitrogênio , Oryza , Filogenia , Raízes de Plantas , Oryza/microbiologia , Oryza/genética , Oryza/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Rizosfera , Salinidade , Adaptação Fisiológica/genética , Simbiose , RNA Ribossômico 16S/genéticaRESUMO
Fine-tuning nanoscale structures, morphologies, and electronic states are crucial for creating efficient water-splitting electrocatalysts. In this study, a method for electronic structure engineering to enhance overall water splitting in a corrosion-resistant electrocatalyst matrix by integrating Pt, P dual-doped Ni4Mo electrocatalysts onto a Ti4O7 nanorod grown on carbon cloth (Pt, P-Ni4Mo-Ti4O7/CC) is introduced. By optimizing platinum and phosphorus concentrations to 1.18% and 2.42%, respectively, low overpotentials are achieved remarkably: 24 mV at 10 mA cm-2 for the hydrogen evolution reaction and 290 mV at 20 mA cm-2 for the oxygen evolution reaction in 1.0 m KOH. These values approach or surpass those of benchmark Pt-C and IrO2 catalysts. Additionally, the Pt, P-Ni4Mo-Ti4O7/CC bifunctional electrocatalyst displays low cell potentials across various mediums, maintaining excellent current retention (96% stability after 40 h in mimic seawater at 20 mA cm-2) and demonstrating strong corrosion resistance and suitability for seawater electrolysis. As a cathode in magnesium/seawater batteries, it achieves a power density of 7.2 mW cm-2 and maintains stability for 100 h. Density functional theory simulations confirm that P, Pt doping-assisted electronic structure modifications augment electrical conductivity and active sites in the hybrid electrocatalysts.
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Renewable electricity-driven seawater splitting presents a green, effective, and promising strategy for building hydrogen (H2)-based energy systems (e.g., storing wind power as H2), especially in many coastal cities. The abundance of Cl- in seawater, however, will cause severe corrosion of anode catalyst during the seawater electrolysis, and thus affect the long-term stability of the catalyst. Herein, seawater oxidation performances of NiFe layered double hydroxides (LDH), a classic oxygen (O2) evolution material, can be boosted by employing tungstate (WO4 2-) as the intercalated guest. Notably, insertion of WO4 2- to LDH layers upgrades the reaction kinetics and selectivity, attaining higher current densities with ≈100% O2 generation efficiency in alkaline seawater. Moreover, after a 350 h test at 1000 mA cm-2, only trace active chlorine can be detected in the electrolyte. Additionally, O2 evolution follows lattice oxygen mechanism on NiFe LDH with intercalated WO4 2-.
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The development of efficient, high-performance catalysts for hydrogen evolution reaction (HER) remains a significant challenge, especially in seawater media. Here, RuIr alloy catalysts are prepared by the polyol reduction method. Compared with single-metal catalysts, the RuIr alloy catalysts exhibited higher activity and stability in seawater electrolysis due to their greater number of reactive sites and solubility resistance. The RuIr alloy has an overpotential of 75 mV@10 mA cm-2, which is similar to that of Pt/C (73 mV), and can operate stably for 100 hours in alkaline seawater. Density functional theory (DFT) calculations indicate that hydrogen atoms adsorbed at the top sites of Ru and Ir atoms are more favorable for HER and are most likely to be the reactive sites. This work provides a reference for developing highly efficient and stable catalysts for seawater electrolysis.
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Seawater electrolysis is a promising but challenging strategy to generate carbon-neutral hydrogen. A grand challenge for hydrogen evolution reaction (HER) from alkaline seawater electrolysis is the development of efficient and stable electrocatalysts to overcome the limitation of sluggish kinetics. Here, a 3D nanorod hybrid catalyst is reported, which comprises heterostructure MoO2@NiMoO4 supported Ru nanoparticles (Ru/ MoO2@NiMoO4) with a size of ≈5 nm. Benefitting from the effect of strongly coupled interaction, Ru/MoO2@NiMoO4 catalyst exhibits a remarkable alkaline seawater hydrogen evolution performance, featured by a low overpotential of 184 mV at a current density of 1.0 A cm-2, superior to commercial Pt/C (338 mV). Experimental observations demonstrate that the heterostructure MoO2@NiMoO4 as an electron-accepting support makes the electron transfer from the Ru nanoparticles to MoO2, and thereby implements the electron redistribution of Ru site. Mechanistic analysis elucidates that the electron redistribution of active Ru site enhances the ability of hydrogen desorption, thereby promoting alkaline seawater HER kinetics and finally leading to a satisfactory catalysis performance at ampere-level current density of alkaline seawater electrolysis.
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The role of tannins (TA), a well-known abundant and ecologically friendly chelating ligand, in metal capture has long been studied. Different kinds of TA-containing adsorbents are synthesized for uranium capture, while most adsorbents suffer from unfavorable adsorption kinetics. Herein, the design and preparation of a TA-containing 2D crosslinked network adsorbent (TANP) is reported. The ≈1.8-nanometer-thick TANP films curl up into micrometer-scale pores, which contribute to fast mass transfer and full exposure of active sites. The coordination environment of uranyl (UO2 2+) ions is explored by integrated analysis of U L3-edge XANES and EXAFS. Density functional theory calculations indicate the energetically favorable UO2 2+ binding. Consequently, TANP with excellent adsorption kinetics presents a high uranium capture capacity (14.62 mg-U g-Ads-1) and a high adsorption rate (0.97 mg g-1 day-1) together with excellent selectivity and biofouling resistance. Life cycle assessment and cost analysis demonstrate that TANP has tremendous potential for application in industrial-scale uranium extraction from seawater.
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Solar-driven interfacial evaporation is recognized as a sustainable and effective strategy for desalination to mitigate the freshwater scarcity issue. Nevertheless, the challenges of oil contamination, salt accumulation, and poor long-term stability of the solar desalination process limit its applications. Herein, a 3D biomass-based multifunctional solar aerogel evaporator is developed for water production with fabricated chitosan/lignin (CSL) aerogel as the skeleton, encapsulated with carbonized lignin (CL) particles and Ti3C2TiX (MXene) nanosheets as light-absorbing materials. Benefitting from its super-hydrophilic wettability, interconnected macropore structure, and high broadband light absorption (ca. 95.50%), the prepared CSL-C@MXene-20 mg evaporator exhibited a high and stable water evaporation flux of 2.351 kg m-2 h-1 with an energy conversion efficiency of 88.22% under 1 Sun (1 kW m-2) illumination. The CSL-C@MXene-20 mg evaporator performed excellent salt tolerance and long-term solar vapor generation in a 3.5 wt.% NaCl solution. Also, its super-hydrophilicity and oleophobicity resulted in superior salt resistance and anti-fouling performance in high salinity brine (20 wt.% NaCl) and oily wastewater. This work offers new insight into the manufacture of porous and eco-friendly biomass-based photothermal aerogels for advanced solar-powered seawater desalination and wastewater purification.
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Direct electrolysis of seawater to generate hydrogen is an attractive approach for storing renewable energy. However, direct seawater splitting suffers from low current density and limited operating stability, which severely hinders its industrialization. Herein, a promising strategy is reported to obtain a nano needle-like array catalyst-CDs-Mn-CoxP on nickel foam, in which the MnâOâC bond tightly binds Mn, Carbon dots (CDs), and CoxP together. The coordination engineering of CDs and Mn not only effectively regulates the electronic structure of CoxP, but also endows the as-prepared catalyst with selectivity and marked long-term stability at ampere-level current density. Low overpotentials of 208 and 447 mV are required to achieve 1000 mA cm-2 for hydrogen evolution reaction (HER) and Oxygen evolution reaction (OER) in simulated seawater, respectively. Cell potentials of 1.78 and 1.86 V are needed to reach 500 and 1000 mA cm-2 in alkaline seawater along with excellent durability for 350 h. DFT studies have verified that the introduction of Mn and CDs effectively shifts the d-band center of Co-3d toward higher energy, thereby strengthening the adsorption of intermediates and enhancing the catalytic activity. This study sheds light on the development of highly effective and stable catalysts for large-scale seawater electrolysis.
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Efficient and sustainable seawater electrolysis is still limited due to the interference of chloride corrosion at the anode. The designing of suitable electrocatalysts is one of the crucial ways to boost electrocatalytic activity. However, the approach may fall short as achieving high current density often occurs in chlorine evolution reaction (CER)-dominating potential regions. Thereby, apart from developing an OER-active high-entropy alloy-based electrocatalyst, the present study also offers a unique way to protect anode surface under high current density or potential by using MoO4 2- as an effective inhibitor during seawater oxidation. The wide variation of d-band center of high-entropy alloy-based electrocatalyst allows great oxygen evolution reaction (OER) proficiency exhibiting an overpotential of 230 mV at current density of 20 mA cm-2. Besides, the electrocatalyst demonstrates impressive stability over 500 h at high current density of 1 A cm-2 or at a high oxidation potential of 2.0 V versus RHE in the presence of a molybdate inhibitor. Theoretical and experimental studies reveal MoO4 2- electrostatically accumulated at anode surface due to higher adsorption ability, thereby creating a protective layer against chlorides without affecting OER.
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Structural regulation is of primary importance in structure-property/application studies of dealloyed nanoporous metals. Three aspects are mainly considered to affect the microstructure of nanoporous metals: design of precursor alloy, choosing of dealloying parameter, and annealing treatment. Herein, through the combination of the above three strategies, the regulation of structure, composition and phase in nanoporous metals are simultaneously achieved. With a dilute Cu99Ag0.75Au0.25 as the precursor, three kinds of nanoporous films are fabricated, including bi-phase nanoporous Cu-Ag-Au (B-NP-CuAgAu), hierarchically nanoporous Au (H-NPG) and single-phase homogeneously nanoporous Au (S-NPG). In situ X-ray diffraction and ex situ characterizations are utilized to reveal the structure/composition/phase evolutions during dealloying of Cu99Ag0.75Au0.25, as well as the macroscopic changes of the dealloyed samples. Notably, the ultrafine ligaments/channels of B-NP-CuAgAu and the two-level nanoporous structure of H-NPG endow them with good broadband light absorption and excellent hydrophilicity, which contribute to their outstanding solar steam generation (SSG) performances. Specially, the B-NP-CuAgAu film shows a more efficient SSG performance with water evaporation rate of 1.49 kg m-2 h-1 and photothermal efficiency of 93.6% at 1 kW m-2, and good seawater desalination ability.
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The seawater electrolysis to produce hydrogen is a significant topic on alleviating the energy crisis. Here, the Fe, Nb-Ni3S2 catalyst is prepared by metal-doping strategy, and it shows high oxygen evolution reaction (OER) activity in alkaline medium, and only needs 1.491 V to deliver a current density of 100 mA cm-2 in simulated seawater. Using Fe, Nb-Ni3S2 as a bifunctional catalyst, the two-electrode electrolyzer only requires a voltage of 1.751 V (without impedance compensation) to drive the current density of 50 mA cm-2, and can run over 150 h stably in the simulated seawater. Importantly, In situ Raman test demonstrates that the outstanding performance of Fe, Nb-Ni3S2 in simulated seawater is ascribed to the in situ formed sulfate protective layer induced by Nb doping, which can effectively inhibit the corrosion of chloride ion, while the protective layer is absent for Fe-Ni3S2. The stable operation of simulated seawater electrolysis under industrial current density further confirms the stability improvement mechanism of forming protective layer. In short, this study provides a new strategy of using Nb dopants inducing the formation of protective layer to enhance the stability of seawater electrolysis.
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The photocatalytic U(VI) reduction is regarded as an effective strategy for recovering uranium. However, its application in seawater uranium extraction poses challenges due to limited reactivity in the presence of carbonate and under atmospheric conditions. In the present study, a photoactive hydrogel made of carboxyl-functionalized g-C3N4/CdS (CCN/CdS) is designed for extracting uranium. The carboxyl groups on g-C3N4 enhance the affinity toward uranyl ions while CdS facilitates the activation of dissolved oxygen. Under atmospheric conditions, the prepared hydrogel catalyst achieves over 80% reduction rate of 0.1 mM U(VI) within 150 min in the presence of carbonate, without the assistance of any electron donors. During the photocatalytic process, U(VI) is reduced to form UO2+x. The hydrogel catalyst exhibits a high uranium extraction capacity of >434.5 mg gâ»1 and the products can be effectively eluted using a 0.1 M NaCO3 solution. Furthermore, this hydrogel catalyst offers excellent stability, good recyclability, outstanding antifouling activity, and ease of separation, all of which are desirable for seawater uranium extraction. Finally, the test in real seawater demonstrates the successful extraction of uranium from seawater using the prepared hydrogel catalyst.
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Efficient and durable electrocatalysts for the hydrogen evolution reaction (HER) in alkaline seawater environments are essential for sustainable hydrogen production. Zeolitic imidazolate framework-8 (ZIF-8) is synthesized through pulsed laser ablation in liquid, followed by pyrolysis, producing N-doped porous carbon (NC). NC matrix serves as a self-template, enabling Pt nanocluster decoration (NC-Pt) via pulsed laser irradiation in liquid. NC-Pt exhibits a large surface area, porous structure, high conductivity, N-rich carbon, abundant active sites, low Pt content, and a strong NC-Pt interaction. These properties enhance efficient mass transport during the HER. Remarkably, the optimized NC-Pt-4 catalyst achieves low HER overpotentials of 52, 57, and 53 mV to attain 10 mA cm-2 in alkaline, alkaline seawater, and simulated seawater, surpassing commercial Pt/C catalysts. In a two-electrode system with NC-Pt-4(-)ÇÇIrO2(+) as cathode and anode, it demonstrates excellent direct seawater electrolysis performance, with a low cell voltage of 1.63 mV to attain 10 mA cm-2 and remarkable stability. This study presents a rapid and efficient method for fabricating cost-effective and highly effective electrocatalysts for hydrogen production in alkaline and alkaline seawater environments.
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Acquiring a highly efficient electrocatalyst capable of sustaining prolonged operation under high current density is of paramount importance for the process of electrocatalytic water splitting. Herein, Fe-doped phosphide (Fe-Ni5P4) derived from the NiFc metal-organic framework (NiFc-MOF) (Fc: 1,1'-ferrocene dicarboxylate) shows high catalytic activity for overall water splitting (OWS). Fe-Ni5P4||Fe-Ni5P4 exhibits a low voltage of 1.72 V for OWS at 0.5 A cm-2 and permits stable operation for 2700 h in 1.0 m KOH. Remarkably, Fe-Ni5P4||Fe-Ni5P4 can sustain robust water splitting at an extra-large current density of 1 A cm-2 for 1170 h even in alkaline seawater. Theoretical calculations confirm that Fe doping simultaneously reduces the reaction barriers of coupling and desorption (O*âOOH*, OOH*âO2 *) in the oxygen evolution reaction (OER) and regulates the adsorption strength of the intermediates (H2O*, H*) in the hydrogen evolution reaction (HER), enabling Fe-Ni5P4 to possess excellent dual functional activity. This study offers a valuable reference for the advancement of highly durable electrocatalysts through the regulation derived from coordination frameworks, with significant implications for industrial applications and energy conversion technologies.