Nickel Species Research Articles

Catalytic hydrogenation of CO2 by composite nickel species supported on KCl-doped graphitic carbon nitride under normal temperature and atmospheric pressure

CO2 can be used as a cheap C1 feedstock to produce value-added chemical products and fuels. In this work, it was proposed for the first time that potassium chloride-doped graphitic carbon nitride-supported composite nickel species (CNS/KCl-g-C3N4) was prepared to catalyze CO2 hydrogenation with potassium borohydride (KBH4) as a hydrogen donor to produce formate at normal temperature and atmospheric pressure. The catalytic activity of CNS/KCl-g-C3N4 reached the best when the nickel loading was optimized as 15 wt%. By using CNS/KCl-g-C3N4, the hydrogen production volume and rate of KBH4 hydrolysis were reduced by 49 % and 32 %, respectively, while the formate concentration was increased by 43 %. It was speculated that the catalytic hydrogenation of CO2 was enhanced due to the chemical adsorption of CO2 on the catalyst surface by interacting with the K-N bonds and -NH2 groups, and the formation of BH4-n(OH)n- (n=0–3) with higher activity from BH4- on the Ni0 sites.

A Rechargeable Urea‐Assisted Zn‐Air Battery With High Energy Efficiency and Fast‐Charging Enabled by Engineering High‐Energy Interfacial Structures

AbstractElectrochemical urea oxidation reaction (UOR) offers a promising alternative to the oxygen evolution reaction (OER) in clean energy conversion and storage systems. Nickel‐based catalysts are regarded as highly promising electrocatalysts for the UOR. However, their effectiveness is significantly hindered by the unavoidable self‐oxidation reaction of nickel species during UOR. To address this challenge, we proposed an interface chemistry modulation strategy to boost UOR kinetics by creating a high‐energy interfacial heterostructure. This heterostructure incorporates Ag at the CoOOH@NiOOH heterojunction interface, where strong interactions significantly promote the electron exchanges at the heterojunction interface between ‐OH and ‐O groups. Consequently, the improved electron delocalization leads to the formation of stronger bonds between Co sites and urea CO(NH2)2, promoting a preference for urea to occupy Co active sites over OH*. The resulting catalyst, Ag−CoOOH@NiOOH, demonstrates ultrahigh UOR activity with a low potential of 1.33 V at 100 mA cm−2. The fabricated catalyst exhibits a mass activity over 11.9 times greater than the initial cobalt oxyhydroxide. The rechargeable urea‐assisted zinc‐air batteries (ZABs) achieve a record‐breaking energy efficiency of 74.56 % at 1 mA cm−2, remarkable durability (1000 hours at a current density of 50 mA cm−2), and quick charge performances.

A Rechargeable Urea-Assisted Zn-Air Battery With High Energy Efficiency and Fast-Charging Enabled by Engineering High-Energy Interfacial Structures.

Electrochemical urea oxidation reaction (UOR) offers a promising alternative to the oxygen evolution reaction (OER) in clean energy conversion and storage systems. Nickel-based catalysts are regarded as highly promising electrocatalysts for the UOR. However, their effectiveness is significantly hindered by the unavoidable self-oxidation reaction of nickel species during UOR. To address this challenge, we proposed an interface chemistry modulation strategy to boost UOR kinetics by creating a high-energy interfacial heterostructure. This heterostructure incorporates Ag at the CoOOH@NiOOH heterojunction interface, where strong interactions significantly promote the electron exchanges at the heterojunction interface between -OH and -O groups. Consequently, the improved electron delocalization leads to the formation of stronger bonds between Co sites and urea CO(NH2)2, promoting a preference for urea to occupy Co active sites over OH*. The resulting catalyst, Ag-CoOOH@NiOOH, demonstrates ultrahigh UOR activity with a low potential of 1.33 V at 100 mA cm-2. The fabricated catalyst exhibits a mass activity over 11.9 times greater than the initial cobalt oxyhydroxide. The rechargeable urea-assisted zinc-air batteries (ZABs) achieve a record-breaking energy efficiency of 74.56 % at 1 mA cm-2, remarkable durability (1000 hours at a current density of 50 mA cm-2), and quick charge performances.

Bifunctional MoNi4/nickel foam electro-catalyst for ultra-efficient oxidation of high-concentration 5-hydroxymethylfurfural and HER.

The electro-catalytic oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) provides an attractive route to produce 2, 5-furandicarboxylic acid (FDCA) as a substitute for terephthalic acid used in the plastics industry. Herein, we prepared MoNi4 alloy on nickel foam (NF) using a simple hydrothermal method followed by hydrogen reduction. Applied MoNi4/NF as the bifunctional electrodes for the electro-catalytic HMF oxidation reaction (HMFOR) and HER, 98.7% FDCA yield and 97.3% Faraday efficiency (FE) can be achieved even with HMF concentration as high as 200 mM. Notably, no obvious deactivation was observed after ten consecutive cycles. In-situ Raman, XANES and EXAFS results show that the nickel species of MoNi4/NF is first oxidized to Ni3+ species under the applied voltage, and after undergoing the electro-catalytic HMFOR, then reduced to Ni2-δ state (with a valence between 0 and +2) due to the electron-donating effect from Mo. MoNi4/NF with more than one electron transfer between Ni3+ and Ni2-δ during the HMFOR enables it to have excellent electro-catalytic oxidation ability toward HMFOR.

Ni-based compounds in multiwalled graphitic shell for electrocatalytic oxygen evolution reactions

Here, we report a general strategy for designing a metal/carbon system, via a facile and environmentally friendly one-step approach, from metal acetate as an active electrocatalyst in oxygen evolution reaction (OER) during water decomposition. As a demonstration, a nanostructured Ni/C composite induced from nickel acetate is revealed in great detail. The resulting material is composed of: metallic nickel (Ni), nickel(II) oxide (NiO), and nickel carbide (Ni3C) coated with a graphitic shell and deposited on a carbon platform. Our findings underscore the prominent role of nickel species, including Ni0, Ni2+, and Ni3+, in driving the catalytic activity. Notably, the catalyst exhibits an overpotential of 170 mV, a Tafel slope of 49 mV·dec−1, an electrocatalytic surface area (ECSA) of 964.7 cm2, and a turnover frequency (TOF) value of 52.8 s−1, surpassing RuO2. The Raman spectra also suggest a graphitic "self-healing" phenomenon post-OER, attributed to the reduction of oxygen-containing groups. Carbon in the system (i) facilitates electron transfer, (ii) allows homogeneous distribution of Ni nanoparticles avoiding their agglomeration, and (iii) promotes durability of the electrocatalyst by serving as a protective barrier, shielding the core metal compounds. What is more, density functional theory (DFT) calculations allowed to optimized geometry of the model cluster Ni8O8(OH)8 describing two different sites on the β-NiOOH surface (001) and two different intermediates, (i)L-OOH and (ii)L-OOH. This facilitated to propose the reaction mechanisms involving both hydroxide ions and water molecules as reducers. Therefore, the chemisorption of OH− and H2O molecules at the NiOOH active center accompanied by bond breakage and the formation of a lattice hydroperoxide as an important intermediate is presumed. What is more, the proposed fabrication method for electroactive metal/carbon composites was validated with an iron and iron/nickel mixture.

Preparation of a finely dispersion nickel-based in-situ pyrolysis catalyst: Influence of lignocellulosic constituents

Metal/biochar catalysts could be synthesized via directly subjecting biomass impregnated with metal salts to pyrolysis. The properties of biochar are intricately linked to the inherent composition of the raw material, which in turn could influence the degree of metal dispersion and its catalytic impact. The poplar sawdust and its fractioned proportion was employed for the preparation of Ni-based biochar catalysts. The work mainly focuses on the impact of lignocellulosic material with diverse compositions on the dispersion of nickel particles during the calcination-pyrolysis co-process. Given that cellulose and holocellulose constituted the majority of the material, the matching catalyst support may encourage the migration of nickel species to produce substantial amounts of particles, perhaps as a result of several reactions such as dehydration and aromatization. In contrast, the utilization of sawdust as a support demonstrated a remarkable effect in dispersing nickel particles, nickel particle size and H2 uptake were 7.0nm and 19.8 μmol/g, respectively, while also displaying exceptional catalytic activity in the hydrogenation of vanillin, with the maximum conversion and 2-methoxy-4-methylphenol (MMP) yield of 99.7% and 69.0%. It has been determined that the presence of lignin in the system has a beneficial impact on the dispersion of nickel and its catalytic activity.

Nickel-Catalyzed Secondary Benzylic C-O Bond Borylation.

A remote steric hindrance ligand (m-tBu)2C6H3PCy2 (L1) was synthesized to promote Ni-catalyzed C-O bond activation. The reaction achieved high yields for secondary benzylic C(sp3)-O borylation in non-π-extended systems under mild conditions. Mechanistic studies indicate that the nickel complex containing 1 equiv of L1 serves as the active catalyst, while increased loading of L1 gives the inactive bisligated Ni species. Acetanilide is crucial for the cross-coupling reaction, which facilitates generation of the monoligated nickel species.

Electrochemical Behaviour of Nickel(II)-Rhenium(VII) And Electrodeposition of Nickel-Rhenium Alloy from Choline Chloride - Urea Deep Eutectic Solvent

The electrochemical behaviour of nickel(II)-rhenium(VII) and the electrodeposition of nickel-rhenium alloy using choline chloride: 2 Urea deep eutectic solvent (Reline DES) is reported. Speciation of nickel(II)-rhenium(VII) in Reline DES was studied using UV -Visible spectroscopy. Cyclic voltammetry of Ni2+-ReO4 − in Reline indicates the simultaneous reduction of two metal ions at glassy carbon electrode controlled by non-reversible diffusion process. Chronoamperograms obtained for the reduction of Ni2+-ReO4 − suggests nucleation and three-dimensional growth of bimetallic phase on electrode surface followed progressive nucleation. Electrodeposition of nickel—rhenium alloy was carried out on copper substrates under galvanostatic and potentiostatic conditions. Smooth and uniform deposits were obtained by galvanostatic deposition. X-ray diffraction analysis of the deposit confirmed it to be nickel-rhenium alloy (at −1.2 V) in amorphous form which upon annealing at 1000 °C crystallizes into hexagonal phase with concurrent morphology change from spherical particles to irregular polygons.

Impact of Nickel Toxicity on Growth, Fruit Quality and Antioxidant Response in Zucchini Squash (Cucurbita pepo L.).

The impact of trace metal elements (TMEs) on plants is one current pollution problem, the severity of which is increasing with industrial development, population growth and inappropriate agricultural practices. The latter can have irreversible effects on ecosystems, including species extinction, trophic chain contamination and altered human health, particularly in the case of consumed plants such as zucchini squash (Cucurbita pepo L.). This study aims to investigate the effects of nickel on various physiological and biochemical parameters of zucchini growth, with a particular focus on how this toxic metal impacts the quality of fruit that is consumed by humans. To achieve this, plants aged 45 days were grown for one month on solid media loaded with different concentrations of Ni (0, 100, 300 and 500 µM). The results showed that exposure of plants to Ni resulted in significantly altered growth and higher accumulation of Ni in the shoots (1314 µg·g-1 DW) than in roots and fruits. Concerning non-enzymatic antioxidants, the results showed that Ni toxicity significantly increased total polyphenols, especially in shoots at 300 µM Ni, while flavonoid content decreased in the roots and shoots in response to Ni treatment. Our results also show that nickel tolerance in C. pepo is ensured by a combination of several mechanisms such as an increase in the content of proline. This species can survive and tolerate, to different degrees, toxic cations at concentrations up to 500 µM but with visible symptoms of toxicity such as chlorosis of the leaves. Indeed, based on thresholds of hyperaccumulation, we can qualify Cucurbita pepo as a hyperaccumulator species of nickel.

Nickel(II)/BINOL-catalyzed enantioselective C–H activation via desymmetrization and kinetic resolution

The field of nickel catalysis has witnessed remarkable growth in recent years. However, the use of nickel catalysts in enantioselective C–H activation remains a daunting challenge because of their variable oxidation states, intricate coordination chemistry, and unpredictable reactivity patterns. Herein, we report an enantioselective C–H activation reaction catalyzed by commercially available and air-stable nickel(II) catalyst. Readily available and simple (S)-BINOL is used as a chiral ligand. This operationally simple protocol enables the synthesis of planar chiral metallocenes in high yields with excellent enantioselectivity through desymmetrization and kinetic resolution. Air-stable planar chiral nickelacycle intermediates are first synthesized via enantioselective C–H nickelation and shown to be possible intermediates of the reaction. Deuterium-labeling studies, alongside the characterization and transformation of chiral nickel(II) species, suggest that C–H cleavage is the enantio-determining step. Moreover, the large-scale synthesis and diverse synthetic transformations underscore the practicality of this protocol.

Self-dispersion of photocatalysts at oil-water interface accelerates H2O2 production and separation

Enhancing the efficiency of photocatalytic charge transfer for H2O2 production and in situ separation of H2O2 from aqueous suspension are crucial, especially when sacrificial agents are involved, for the advancement of this environmental-friendly process. In this study, we propose that the production and separation of H2O2 can be significantly enhanced at a self-assembled tri-phase system (water/photocatalyst/benzyl alcohol) compared to the suspension system. To prove this, we have employed titania nanotube (TNT) as a representative photocatalyst with efficient oxygen adsorption and modified it with organic ligand (octadecyl phosphate, OPA) and nickel species to modulate its hydrophobicity and dispersity at the interface, resulting in improved H2O2 yield. The modified TNT photocatalyst demonstrates efficient H2O2 production reaching a concentration of 5.1 mM after 75 mins under optimized conditions and an initial rate of 7500 μmol/g/h within first 6 h that even exceeding reported noble metals modified TiO2 photocatalysts. This enhanced activity is attributed to multiple effects including homogeneous dispersion of photocatalyst at the oil-water interface, efficient O2 adsorption and transfer, separated redox reactions at different phases, timely diffusion of H2O2 into bulk aqueous solution, and potential solvent-induced polarization effect on charge transfer, which result from the special oil-water interface that stabilizing photocatalysts and inducing photocatalytic O2 reduction. As proof-of-concept demonstrations show successful photosynthesis of H2O2 using natural solar light followed by utilizing the generated pure H2O2 solution for bacteria inactivation, indicating that interfacial photocatalytic systems offer promising potential for green H2O2 synthesis and application.

Hyperaccumulation of nickel but not selenium drives floral microbiome differentiation: A study with six species of Brassicaceae.

Intraspecific variation in flower microbiome composition can mediate pollination and reproduction, and so understanding the community assembly processes driving this variation is critical. Yet the relative importance of trait-based host filtering and dispersal in shaping among-species variation in floral microbiomes remains unknown. Within two clades of Brassicaceae, we compared diversity and composition of floral microbiomes in natural populations of focal nickel and selenium hyperaccumulator species and two of their non-accumulating relatives. We assessed the relative strengths of floral elemental composition, plant phylogenetic distance (host filtering), and geography (dispersal) in driving floral microbiome composition. Species in the nickel hyperaccumulator clade had strongly divergent floral microbiomes, the most of that variation driven by floral elemental composition, followed by geographic distance between plant populations and, lastly, phylogenetic distance. Conversely, within the selenium hyperaccumulator clade, floral microbiome divergence was much lower among the species and elemental composition, geography, and plant phylogeny were far weaker determinants of microbiome variation. Our results show that the strength of elemental hyperaccumulation's effect on floral microbiomes differs substantially among plant clades, possibly due to variation in elements as selective filters or in long-distance dispersal probability in different habitats.

Solar H2O2 production with carbon dots and nickel co-modified titania nanotube photocatalyst stabilized at water/benzyl alcohol interface

An interfacial reaction system with the advantage of in situ H2O2 production and separation has been developed, in which titania nanotube (TNT) photocatalyst modified by nickel species and carbon dots (CDs) can self-stabilize at interface of water/benzyl alcohol. Under visible light irradiation, the CDs/Ni-TNT yields H2O2 with an initial rate of 385.6 μmol/g/h. The improved activity could be attributed to multiple effects such as sufficient oxygen adsorption and mass transfer, separated reduction and oxidation sites at different phases, and rapid diffusion of H2O2 from the interfacial region into bulk aqueous solution.

Preparation of Ni2P with a Surface Nickel Phosphosulfide Layer by Reduction of Mixtures of Na4P2S6 and NiCl2

AbstractA series of physical mixtures of Na4P2S6 and NiCl2 (P‐NiPS(x), where x represents the P/Ni molar ratio) were employed for the preparation of Ni2P. For comparison, a sulfur‐containing Ni2P catalyst (Ni2P‐S) and a sulfur‐free Ni2P catalyst (Ni2P‐TPR) were prepared by reduction of Ni2P2S6 and a nickel phosphate precursor, respectively. The reduction of the P‐NiPS(x) precursors with P/Ni ratios above 2/3 yielded Ni2P catalysts with a distinct nickel phosphosulfide layer (NiPS(x)), and the Ni2P phase started to form at ca. 200 °C. The reduction of Ni2P2S6 to Ni2P most likely follows a disproportionation mechanism. The P3+ species in Ni2P2S6 disproportionate to PH3 and P5+ during the reduction, and PH3 further reacts with nickel and sulfur species to form Ni2P and the surface nickel phosphosulfide layer. The sulfur atoms in the nickel phosphosulfide phase were in the form of S2−. The introduction of sulfur to Ni2P favored the hydrogenation pathway of the hydrodesulfurization (HDS) of dibenzothiophene (DBT), but hardly affected the direct desulfurization (DDS) pathway and inhibited the hydrogenation of biphenyl. The DDS pathway rate constants of DBT HDS over the Ni2P‐TPR and NiPS(x) catalysts were observed to increase linearly with the increase in their surface Ni atomic concentrations.

Nickel Single‐Atoms Modified Organic Anodes with Enhanced Reaction Kinetics for Stable Potassium‐Ion Batteries

AbstractThe redox‐active organic compounds including potassium 1,1′‐biphenyl‐4,4′‐dicarboxylate (K‐BPDC) are attracting considerable attention as anodes for potassium‐ion batteries (PIBs). Nevertheless, the practical applications of K‐BPDC organic anodes are severely hindered by short cycle life due to their relatively sluggish redox kinetics and instability. In this work, Ni single atoms (up to 6 wt.%) are implanted into K‐BPDC (NiSA@K‐BPDC) by using an electrochemical‐induced reconstruction (EIR) strategy to enhance the reaction kinetics and stability of PIBs. During the EIR process, Ni‐based metal‐organic framework (Ni‐BPDC) is in situ reconstructed into K‐BPDC by replacing Ni2+ with K+ to make the rest nickel species exist in the form of single atoms in K‐BPDC. By kinetic analysis and theoretical calculations, it is uncovered that the Ni single atoms supported on K‐BPDC efficiently redistribute the local charge of K‐BPDC to accelerate the K+ transport rate, and thermodynamically reduce the redox energy barrier. As a result, the NiSA@K‐BPDC anode exhibits outstanding cycle stability with 88.5% capacity retention during 4000 cycles at 1 A g−1 and an excellent rate capability (114 mAh g−1 at 2 A g−1). This study opens up a new door to the design of organic anodes with single atoms for high‐performance PIBs.

Investigating the Metal-TiO2 Influence for Highly Selective Photocatalytic Oxidation of Methane to Methanol.

Methane conversion to valuable chemicals is a highly challenging and desirable reaction. Photocatalysis is a clean pathway to drive this chemical reaction, avoiding the high temperature and pressure of the syngas process. Titanium dioxide, being the most used photocatalyst, presents challenges in controlling the oxidation process, which is believed to depend on the metal sites on its surface that function as heterojunctions. Herein, we supported different metals on TiO2 and evaluated their activity in methane photooxidation reactions. We showed that Ni-TiO2 is the best photocatalyst for selective methane conversion, producing impressively high amounts of methanol (1.600 μmol·g-1) using H2O2 as an oxidant, with minimal CO2 evolution. This performance is attributed to the high efficiency of nickel species to produce hydroxyl radicals and enhance H2O2 utilization as well as to induce carrier traps (Ti3+ and SETOVs sites) on TiO2, which are crucial for C-H activation. This study sheds light on the role of catalyst structure in the proper control of CH4 photoconversion.

Effect of Active Phase Precursor on Structural, Textural and Catalytic Properties of the Model NiOx/CeO2 System Active in Dry Reforming of Methane

The current paper is devoted to the synthesis of ceria-supported nickel-based catalysts starting from different precursors of the nickel active phase. Thermal decomposition of metal-containing precursors, deposited onto stable supports by dry impregnation, belongs to the industrially preferred, simple ways of catalyst preparation. The synthesized series of NiOx/CeO2 catalysts have been tested in dry methane reforming (DMR), in which two greenhouse gases, i.e., CO2 and CH4, are simultaneously converted into syngas. Both reaction progress and stability of the catalyst strongly depend on nickel speciation, which in turn can be determined by the nature of the chosen precursor. Contrary to relatively many studies focused on the importance of synthetic methods and conditions on nickel speciation, the effect of precursor nature on structural, textural, and functional properties of catalytic systems has neither been discussed much nor fully understood. The main goal of this paper was to elucidate the effect of precursors on the properties of NiOx/CeO2. Consequences of the use of various nickel precursors (simple inorganic salts, organometallic complexes, and chelates) have been analyzed in detail from the viewpoint of their beneficial influence on the catalytic performance of NiOx/CeO2 system (containing 3 wt. % of Ni) tested in DMR.

Trisodium Citrate as a Double-Edged Sword: Selective Etching Prussian Blue Analog Nanocubes into Orthogonal Frustums and Their Derivatives for Supercapacitors.

The construction of novel structured Prussian blue analogs (PBAs) by chemical etching has attracted the most attention to PBA derivatives with outstanding performance. In this work, the unprecedented PBA orthogonal frustums are first prepared from nanocubes through a selective chemical etching approach using trisodium citrate as an etchant. The citrate ions can chelate with nickel species from the edges/corners of NiCo-PBA nanocubes and then disintegrate NiCo-PBAs resulting in the generation of NiCo-PBA orthogonal frustums. The derived CoNi2S4/Co0.91S composites still inherit the original orthogonal frustum structure and possess outstanding supercapacitor performance. This study develops a popularized method to construct novel structured PBAs and brings inspiration for designing PBA-based electrodes with advanced electrochemical performance.

Dual Nickel- and Photoredox-Catalyzed Asymmetric Reductive Cross-Couplings: Just a Change of the Reduction System?

ConspectusIn recent years, nickel-catalyzed asymmetric coupling reactions have emerged as efficient methods for constructing chiral C(sp3) carbon centers. Numerous novel approaches have been reported to rapidly construct chiral carbon-carbon bonds through nickel-catalyzed asymmetric couplings between electrophiles and nucleophiles or asymmetric reductive cross-couplings of two different electrophiles. Building upon these advances, our group has been devoted to interrogating dual nickel- and photoredox-catalyzed asymmetric reductive cross-coupling reactions.In our endeavors over the past few years, we have successfully developed several dual Ni-/photoredox-catalyzed asymmetric reductive cross-coupling reactions involving organohalides. While some probably think that this system is just a change of the reduction system from traditional metal reductants to a photocatalysis system, a question that we also pondered at the beginning of our studies, both the achievable reaction types and mechanisms suggest a different conclusion: that this dual catalysis system has its own advantages in the chiral carbon-carbon bond formation. Even in certain asymmetric reactions where the photocatalysis regime functions only as a reducing system, the robust reducing capability of photocatalysts can effectively accelerate the regeneration of low-valent nickel species, thus expanding the selectable scope of chiral ligands. More importantly, in many transformations, besides reducing nickel catalysts, the photocatalysis system can also undertake the responsibility of alkyl radical formation, thereby establishing two coordinated, yet independent catalytic cycles. This catalytic mode has been proven to play a crucial role in achieving diverse asymmetric coupling reactions with great challenges.In this Account, we elucidate our understanding of this system based on our experience and findings. In the Introduction, we provide an overview of the main distinctions between this system and traditional Ni-catalyzed asymmetric reductive cross-couplings with metal reductants and the potential opportunities arising from these differences. Subsequently, we outline various chiral carbon-carbon bond-forming types obtained by this dual Ni/photoredox catalysis system and their mechanisms. In terms of chiral C(sp3)-C(sp2) bond formation, extensive discussion focuses on the asymmetric arylations of α-chloroboronates, α-trifluoromethyl alkyl bromides, α-bromophosphonates, and so on. In the realm of chiral C(sp3)-C(sp) bond formation, asymmetric alkynylations of α-bromophosphonates and α-trifluoromethyl alkyl bromides have been presented herein. Regarding C(sp3)-C(sp3) bond formation, we take the asymmetric alkylation of α-chloroboronates as a compelling example to illustrate the great efficiency of this dual catalysis system. This summary would enable a better grasp of the advantages of this dual catalysis system and clarify how the photocatalysis regime facilitates enantioselective transformations. We anticipate that this Account will offer valuable insights and contribute to the development of new methodologies in this field.

Regulating the redox cycle of nickel species for efficient seawater electrolysis

Promoting the self-reconstruction of NiFe-based catalysts represents a promising approach to facilitate seawater splitting, albeit with significant challenges. Herein, the redox cycle of Ni species is subtly regulated by decorating NiFe hydroxides with vanadium. Both experimental and theoretical studies demonstrate that the incorporation of V boosts the self-reconstruction of NiFe hydroxides and allows a superior OER performance on account of diminished propensity for chlorine adsorption and optimized binding energy of oxygen-containing intermediates. Consequently, the NiFeV/NF catalyst delivers 2.0 A cm−2 at an ultralow overpotential of 369 mV in 1.0 M KOH and exhibits exceptional stability for 720 h at 20 A in an alkaline membrane electrode assembly (MEA) electrolyzer. In alkaline seawater, it achieves prolonged stability, surpassing 240 h at 500 mA cm−2 with OER selectivity of 99 %. This work significantly advances the field of seawater electrolysis powered by marine renewables, paving the way for on-site hydrogen production.