Asymmetric Charge Distribution Research Articles

Asymmetric Charge Distribution in Atomically Precise Metal Nanoclusters for Boosted CO2 Reduction Catalysis.

Recently, atomically precise metal nanoclusters (NCs) have been widely applied in CO2 reduction reaction (CO2RR), achieving exciting activity and selectivity and revealing structure-performance correlation. However, at present, the efficiency of CO2RR is still unsatisfactory and cannot meet the requirements of practical applications. One of the main reasons is the difficulty in CO2 activation due to the chemical inertness of CO2. Constructing symmetry-breaking active sites is regarded as an effective strategy to promote CO2 activation by modulating electronic and geometric structure of CO2 molecule. In addition, in the subsequent CO2RR process, asymmetric charge distributed sites can break the charge balance in adjacent adsorbed C1 intermediates and suppress electrostatic repulsion between dipoles, benefiting for C-C coupling to generate C2+ products. Although compared to single atoms, metal nanoparticles, and inorganic materials the research on the construction of asymmetric catalytic sites in metal NCs is in a newly-developing stage, the precision, adjustability and diversity of metal NCs structure provide many possibilities to build asymmetric sites. This review summarizes several strategies of construction asymmetric charge distribution in metal NCs for boosting CO2RR, concludes the mechanism investigation paradigm of NCs-based catalysts, and proposes the challenges and opportunities of NCs catalysis.

Dual Active Sites with Charge‐asymmetry in Organic Semiconductors Promoting C−C Coupling for Highly Efficient CO2 Photoreduction to Ethanol

AbstractSelective CO2 photoreduction into high‐energy‐density and high‐value‐added C2 products is an ideal strategy to achieve carbon neutrality and energy shortage, but it is still highly challenging due to the large energy barrier of the C−C coupling step and severe exciton annihilation in photocatalysts. Herein, strong and localized charge polarization is successfully induced on the surface of melon‐based organic semiconductors by creating dual active sites with a large charge asymmetry. Confirmed by multiscale characterization and theoretical simulations, such asymmetric charge distribution, originated from the oxygen dopants and nitrogen vacancies over melon‐based organic semiconductors, reduces exciton binding energy and boosts exciton dissociation. The as‐formed charge polarization sites not only donate electrons to CO2 molecules but also accelerate the coupling of asymmetric *CO*CO intermediates for CO2 photoreduction into ethanol by lowering the energy barrier of this process. Consequently, an exceptionally high selectivity of up to 97 % for C2H5OH and C2H5OH yield of 0.80 mmol g−1 h−1 have been achieved on this dual active sites organic semiconductor. This work, with its potential applicability to a variety of non‐metal multi‐site catalysts, represents a versatile strategy for the development of advanced catalysts tailored for CO2 photoreduction reactions.

Dual Active Sites with Charge-asymmetry in Organic Semiconductors Promoting C-C Coupling for Highly Efficient CO2 Photoreduction to Ethanol.

Selective CO2 photoreduction into high-energy-density and high-value-added C2 products is an ideal strategy to achieve carbon neutrality and energy shortage, but it is still highly challenging due to the large energy barrier of the C-C coupling step and severe exciton annihilation in photocatalysts. Herein, strong and localized charge polarization is successfully induced on the surface of melon-based organic semiconductors by creating dual active sites with a large charge asymmetry. Confirmed by multiscale characterization and theoretical simulations, such asymmetric charge distribution, originated from the oxygen dopants and nitrogen vacancies over melon-based organic semiconductors, reduces exciton binding energy and boosts exciton dissociation. The as-formed charge polarization sites not only donate electrons to CO2 molecules but also accelerate the coupling of asymmetric *CO*CO intermediates for CO2 photoreduction into ethanol by lowering the energy barrier of this process. Consequently, an exceptionally high selectivity of up to 97 % for C2H5OH and C2H5OH yield of 0.80 mmol g-1 h-1 have been achieved on this dual active sites organic semiconductor. This work, with its potential applicability to a variety of non-metal multi-site catalysts, represents a versatile strategy for the development of advanced catalysts tailored for CO2 photoreduction reactions.

Building Asymmetric Zn-N3 Bridge between 2D Photocatalyst and Co-catalyst for Directed Charge Transfer toward Efficient H2O2 Synthesis.

Two-dimensional (2D) polymeric semiconductors are a class of promising photocatalysts; however, it remains challenging to facilitate their interlayer charge transfer for suppressed in-plane charge recombination and thus improved quantum efficiency. Although some strategies, such as π-π stacking and van der Waals interaction, have been developed so far, directed interlayer charge transfer still cannot be achieved. Herein, we report a strategy of forming asymmetric Zn-N3 units that can bridge nitrogen (N)-doped carbon layers with polymeric carbon nitride nanosheets (C3N4-Zn-N(C)) to address this challenge. The symmetry-breaking Zn-N3 moiety, which has an asymmetric local charge distribution, enables directed interfacial charge transfer between the C3N4 photocatalyst and the N-doped carbon co-catalyst. As evidenced by femtosecond transient absorption spectroscopy, charge separation can be significantly enhanced by the interfacial asymmetric Zn-N3 bonding bridges. As a result, the designed C3N4-Zn-N(C) catalyst exhibits dramatically enhanced H2O2 photosynthesis activity, outperforming most of the reported C3N4-based catalysts. This work highlights the importance of tailoring interfacial chemical bonding channels in polymeric photocatalysts at the molecular level to achieve effective spatial charge separation.

Building Asymmetric Zn−N3 Bridge between 2D Photocatalyst and Co‐catalyst for Directed Charge Transfer toward Efficient H2O2 Synthesis

AbstractTwo‐dimensional (2D) polymeric semiconductors are a class of promising photocatalysts; however, it remains challenging to facilitate their interlayer charge transfer for suppressed in‐plane charge recombination and thus improved quantum efficiency. Although some strategies, such as π–π stacking and van der Waals interaction, have been developed so far, directed interlayer charge transfer still cannot be achieved. Herein, we report a strategy of forming asymmetric Zn−N3 units that can bridge nitrogen (N)‐doped carbon layers with polymeric carbon nitride nanosheets (C3N4−Zn−N(C)) to address this challenge. The symmetry‐breaking Zn−N3 moiety, which has an asymmetric local charge distribution, enables directed interfacial charge transfer between the C3N4 photocatalyst and the N‐doped carbon co‐catalyst. As evidenced by femtosecond transient absorption spectroscopy, charge separation can be significantly enhanced by the interfacial asymmetric Zn−N3 bonding bridges. As a result, the designed C3N4−Zn−N(C) catalyst exhibits dramatically enhanced H2O2 photosynthesis activity, outperforming most of the reported C3N4‐based catalysts. This work highlights the importance of tailoring interfacial chemical bonding channels in polymeric photocatalysts at the molecular level to achieve effective spatial charge separation.

Point-defect-induced electronic polarization to enhance H* generation for removal of bisphenol A

Intrinsic point defects in metal core-shell materials can regulate electron redistribution, thereby reducing catalytic energy barriers and enhancing their ORR activity. However, their specific contributions to electron transfer and mass transport pathways remain unclear. In this study, defect-rich hollow OCo@Co3O4 nanoparticles were successfully synthesized using ZIF-67(Co) as a sacrificial template through controlled annealing and internal electric field substitution reactions. High-resolution electron microscopy analysis and density functional theory (DFT) calculations co-revealed the growth mechanism of Co and O vacancies, as well as antisite defects. The formation of oxygen vacancies significantly lowered the energy barrier for Co vacancy formation, playing a crucial bridging role in the development of antisite defects. The electric field polarization induced by Co-O atomic displacement resulted in asymmetric charge distribution, optimizing the adsorption of active hydrogen (H*) and oxygen atoms and facilitating the generation and release of reactive oxygen species (ROS). Electrocatalytic experiments demonstrated that under the combined action of singlet oxygen (1O2) and H*, bisphenol A (BPA) can be efficiently degraded. This study successfully bridges the knowledge gap between atomic defects and advanced electrocatalysis, providing a new perspective and insight for the in-depth analysis of the structure-performance relationship of electrocatalyst materials in the future.

AuAg plasmonic nanoalloys with asymmetric charge distribution on CeO2 nanorods for selective photocatalytic CO2‐to‐CH4 conversion

AbstractConverting CO2 under mild conditions by employing semiconductor photocatalysts is promising to address global environmental issues. However, the current CO2 conversion efficiency is limited by the difficulty activating the thermodynamically stable CO2 molecules. Constructing plasmonic nanoalloy‐based photocatalytic systems with significant localized surface plasmon resonance (LSPR) is full of potential but remains a vast challenge. In this work, AuAg plasmonic nanoalloys were incorporated on CeO2 nanorods (designated as AuAg–CeO2) to achieve selective photoreduction of CO2. The result displays that Ag can serve as a superior electron modifier to promote the electron enrichment of Au, thus producing asymmetric charge distributions to boost the selective conversion of CO2. Furthermore, the improved LSPR effect on AuAg–CeO2 induces the generation of high‐energy hot electrons under irradiation, enhancing the reactivity of electrons for CO2 photoreduction. Due to the aforementioned effects, AuAg–CeO2 exhibits a high CO2‐to‐CH4 performance of 92.6 μmol g−1 through a 3‐h test and a high CH4 selectivity of 94.5%, up to 2.6, 8.7, and 17.1 times higher than the activity of Au–CeO2, pure CeO2, and Ag–CeO2, respectively. This work can provide a new perspective for constructing high‐performance catalysts for photocatalytic CO2 reduction.

Asymmetric Charge Distribution in One-dimensional Metal-Organic Assemblies to Promote Photocatalytic Hydrogen Evolution.

The local charge distribution of photocatalyst is crucial to the catalytic activity due to its influence on the charge separation process. Herein, we report two one-dimensional Ni-based metal-organic assemblies for efficient photocatalytic hydrogen evolution without using noble-metal cocatalysts. By adjusting the aromatic ring in the center of the tricarboxylic ligand, the photocatalytic hydrogen evolution activity was increased from 1715 to 2652 μmol h-1 g-1. The detailed mechanism study shows that the introduced nitrogen atoms in the ligands of the metal-organic coordination assembly could modulate the local charge distribution, and yielding a significant enhancement of the molecular dipole moment which engenders a propulsive force for the effective separation and transport of photoinduced charge carriers. This work provides insights into the local charge distribution via ligand modulation for enhancing the activity of photocatalysts.

Built-in electric field-driven electron transfer behavior at Ru-RuP2 heterointerface fosters efficient and CO-resilient alkaline hydrogen oxidation

Exploiting a cost-effective electrocatalyst for hydrogen oxidation reaction (HOR) with high-performance and CO poisoning resistance is essential for the widespread application of alkaline anion exchange membrane fuel cells (AEMFCs). Herein, we craft a unique Ru-RuP2 heterostructure within hollow mesoporous carbon sphere (Ru-RuP2@C) using phosphide-controlled phase-transition approach. Benefiting from the interfacial electron transfer from RuP2 to Ru, the Ru-RuP2@C electrocatalyst exhibits impressive HOR performance with a mass activity of 2.87 mA μgRu−1. Notably, Ru-RuP2@C demonstrates strong tolerance to 1000 ppm CO, a capability lacking in PtRu/C and Pt/C. When serves as an anode catalyst for AEMFC, it achieves a peak power density of 521 mW cm−2, comparable to Pt/C. Experimental and theoretical analyses reveal that the built-in electric field, resulting from work function differences, creates an asymmetric charge distribution that modulates the d-band center of Ru-RuP2@C. This optimizes the adsorption strength of hydrogen and hydroxide intermediates, thereby accelerating HOR catalytic kinetics.

In-Situ Anchoring of Co Single-Atom Synergistically with Cd Vacancy of Cadmium Sulfide for Boosting Asymmetric Charge Distribution and Photocatalytic Hydrogen Evolution.

In the context of reshaping the energy pattern, designing and synthesizing high-performance noble metal-free photocatalysts with ultra-high atomic utilization for hydrogen evolution reaction (HER) still remains achallenge. In a streamlined synthesis process, in-situ single atom anchoring is performed in parallel with HER by irradiating a precursory defect-state CdS/Co suspension (Co-DCdS-Ss) system under simulated sunlight and the in-situ synthesizing single-atom Co photocatalyst (Co5:DCdS) exhibits further improved catalytic performance (60.10 mmolg-1h-1) compared with Co-DCdS-Ss (18.09 mmolg-1h-1), reaching an apparent quantum yield of 57.6% at 500nm and a solar-chemical energy conversion efficiency (SCC) of 6.26% at AM 1.5G. In-depth characterization tests and density functional theory (DFT) calculations prove that the anchoring of Co single atom deepens the asymmetric charge distribution of the two-coordination S atom adjacent to the cadmium vacancy (VCd). The synergy between electron delocalization VCd and Co single atom on the catalyst surface is constructed, which bifunctional sites responsible for boosting water adsorption-dissociation and hydrogen evolution. This study advances the understanding of the underlying mechanisms of synergy between surface defects and metal single atoms and opens a new horizon for the development of advanced materials in the field of photocatalysis.

Synthesis, photophysical properties, and in-silico nonlinear optics of 3-hydroxy-N-phenyl-2-naphthamide and its acetate, acrylate, and benzoate derivative

In this study, we report the successful growth of single crystals of 3-hydroxynaphthalene-2-carboxanilides (NAS) with a monoclinic structure in the P21/c space group and space group number of 14 for the first time. We have developed a yield and time-effective modified synthetic procedure using a synthetic reactor by replacing the traditional microwave method. Additionally, acylated derivatives of NAS, including novel acryloyl derivative (NAS AC), are synthesized with a modified procedure, replacing pyridine with triethylamine.We investigate the structural, photophysical, and quantum chemical properties of N-(4-acetylphenyl)-2-oxo-2H-chromene-3-carboxamide (NAS) and its acylated derivatives (NAS AC, NAS ACT, NAS BZ). Photophysical studies reveal significant Stokes shifts observed in different solvents, including time-enhanced fluorescence in DMSO, attributed to solvent relaxation processes. Natural bond orbital (NBO) analysis, molecular electrostatic potential (MEP) maps, and frontier molecular orbital (FMO) provide insights into electronic interactions and asymmetric charge distribution. Low-lying LUMO values of these compounds (-2.31 eV to -1.95 eV) support candidature for the electron acceptor applications. Nonlinear optical properties were thoroughly investigated, with NAS displaying the highest static first-order hyperpolarizability (17.89 × 10−30 esu) and NAS BZ exhibiting the highest second-order hyperpolarizability (113.09 × 10−36 esu), indicating significant nonlinear optical responses. Thermal stability (TGA and DTA) highlights the significant range of temperatures for the NLO applications.

Dynamic Control of Asymmetric Charge Distribution for Electrocatalytic Urea Synthesis.

Constructing dual catalytic sites with charge density differences is an efficient way to promote urea electrosynthesis from parallel and CO2 reduction yet still challenging in static system. Herein, a dynamic system is constructed by precisely controlling the asymmetric charge density distribution in an Au-doped coplanar Cu7 clusters-based 3D frameworkcatalyst (Au@cpCu7CF). In Au@cpCu7CF, the redistributed charge between Au and Cu atoms changed periodically with the application of pulse potentials switching between -0.2 and -0.6 V and greatly facilitated the electrosynthesis of urea. Compared with the static condition of pristine cpCu7CF (FEurea = 5.10%), the FEurea of Au@cpCu7CF under pulsed potentials is up to 55.53%. Theoretical calculations demonstrated that the high potential of -0.6V improved the adsorption of *HNO2 and *NH2 on Au atoms and inhibited the reaction pathways of by-products. While at the low potential of -0.2V, the charge distribution between Au and Cu atomic sites facilitated the thermodynamic C-N coupling step. This work demonstrated the important role of asymmetric charge distribution under dynamic regulation for urea electrosynthesis, providing a new inspiration for precise control of electrocatalysis.

Enhancing Built‐In Electric Field via Defect‐Mediated Interfacial Chemical Bond Construction in Chalcogenide Heterojunction for Alcohol Photooxidation Coupled with H2 Production

AbstractRationally designing nanostructures based on an adequate understanding of structure‐performance relationships is key for directional charge transfer regulation in heterojunction photocatalysts. A general strategy is developed for synthesizing bifunctional Sv‐chalcogenide/Ti3C2 Schottky junctions (Sv = sulfur vacancies, chalcogenides containing CdS, CdIn2S4, ZnIn2S4, ZnS, CuInS2) featuring a giant built‐in electric field (BIEF) via defect‐mediated heterocomponent anchorage, which consists of sulfur vacancy modulation of chalcogenides and Ti3C2 nanoparticle anchoring at defects via interfacial Metal─Oxygen (M─O) bonds. These heterojunctions have the distinctive interface structure of semicoherent phase boundaries and a directionally aligned BIEF pointing from chalcogenides to Ti3C2. The enhanced BIEF creates an asymmetrical charge distribution, which not only governs the charge migration behavior by enabling charge carrier localization and delocalized electron transport continuity but also regulates the molecular catalytic behavior by optimizing pivotal intermediate adsorption/activation (*Ar‐CH(R2)‐OH in dehydrogenation and H* in H2 evolution) in selective alcohol photooxidation coupled with H2 generation. Encouragingly, Sv‐chalcogenide/Ti3C2 exhibits unprecedented performance (up to 13.34‐fold higher efficiency than unmodulated chalcogenides) and good substrate compatibility for various alcohols. This work demonstrates the synergistic effects of surface electron density control and interfacial interaction modulation in regulating BIEFs, elucidating the substantial impact of reinforced BIEF on carrier transport properties and molecular catalytic behavior.

Precisely Regulating Asymmetric Charge Distribution by Single-Atom Central Doped Ag-Based Series Clusters for Enhanced Photoreduction of CO2 to Alcohol Fuels.

High efficiently photocatalytic CO2 reduction (CO2RR) into liquid fuels in pure water system remains challenged. Iron polyphthalocyanine (FePPc) with strong light harvesting, unique Fe-N4 structure, abundant pores, and good stability could serve as a promising catalyst for CO2 photoreduction. To further improve the catalytic efficiency, herein, symmetry-breaking Fe sites are constructed by coupling with atomically precise M1Ag24 (M=Ag, Au, Pt) series clusters. Especially, the introduction of Pt1Ag24 causes the most asymmetric charge distribution of Fe in FePPc (followed by Au1Ag24 and Ag25), leading to the favorable CO2 adsorption and activation. In addition, Pt1Ag24-FePPc exhibits the most effective photogenerated carriers transfer and separation. As a result, Pt1Ag24-FePPc shows the methanol/ethanol yield of 48.55/32.97 μmol·gcat-1·h-1 in H2O-CO2 system under visible light irradiation, ~ 1.65/1.25-fold, 1.83/1.37-fold, and 3.6/1.61-fold higher than that of Au1Ag24-FePPc, Ag25-FePPc, and FePPc, respectively. This work provides a concept for precisely construction and regulation symmetry-breaking sites of cluster-based catalysts for effective CO2 conversion.

Precisely Regulating Asymmetric Charge Distribution by Single‐Atom Central Doped Ag‐Based Series Clusters for Enhanced Photoreduction of CO2 to Alcohol Fuels

AbstractHigh efficiently photocatalytic CO2 reduction (CO2RR) into liquid fuels in pure water system remains challenged. Iron polyphthalocyanine (FePPc) with strong light harvesting, unique Fe‐N4 structure, abundant pores, and good stability could serve as a promising catalyst for CO2 photoreduction. To further improve the catalytic efficiency, herein, symmetry‐breaking Fe sites are constructed by coupling with atomically precise M1Ag24 (M=Ag, Au, Pt) series clusters. Especially, the introduction of Pt1Ag24 causes the most asymmetric charge distribution of Fe in FePPc (followed by Au1Ag24 and Ag25), leading to the favorable CO2 adsorption and activation. In addition, Pt1Ag24‐FePPc exhibits the most effective photogenerated carriers transfer and separation. As a result, Pt1Ag24‐FePPc shows the methanol/ethanol yield of 48.55/32.97 μmol ⋅ gcat−1 ⋅ h−1 in H2O‐CO2 system under visible light irradiation, ~1.65/1.25‐fold, 1.83/1.37‐fold, and 3.60/1.61‐fold higher than that of Au1Ag24‐FePPc, Ag25‐FePPc, and FePPc, respectively. This work provides a concept for precisely construction and regulation symmetry‐breaking sites of cluster‐based catalysts for effective CO2 conversion.

Electronic structure engineering of asymmetric coupled dual-cocatalysts on carbon nitride for synergistically enhancing photocatalytic H2 evolution

Photocatalytic hydrogen production is a promising strategy to solve the energy crisis and environmental issues. Herein, an efficient photocatalyst consisting of the MoP quantum dots and Pt nanoclusters dual cocatalysts anchored on polymeric carbon nitride matrix (denoted as Mo-Pt/CN) is designed for achieving boosted photocatalytic H2 production. Benefiting from the synergy of dual cocatalysts, Mo-Pt/CN photocatalyst delivers an impressive H2 evolution rate of 11.26 mmol·g−1·h−1, which is 6.43 and 25.02 times higher than those of the Pt/CN and Mo/CN photocatalyst, respectively. Systematic experiments combining with theoretical calculations reveal that the enhanced photocatalytic activity attributes to the synergy of asymmetrically geometrical deployment between MoP and Pt NCs dual cocatalysts, which induces asymmetric charge distributions and tailors the d-band center to optimize the adsorption behaviors of H2O* and H* intermediates on Mo-Pt dual sites, respectively, thus facilitating H2O* activation-dissociation and simultaneously achieving thermoneutral H* adsorption free energy (ΔGH*) for speeding up the H2 evolution kinetics.

Empowering lithium-ion storage: unveiling the superior performance of niobium-based oxide/perovskite heterojunction with built-in electric field

The increasing demand for high-performance electrode materials in lithium-ion batteries has driven significant attention towards Nb2O5 due to its high working voltage, large theoretical capacity, environmental friendliness, and cost-effectiveness. However, inherent drawbacks such as poor electrical conductivity and sluggish electrochemical reaction kinetics have hindered its lithium storage performance. In this study, we introduced KCa2Nb3O10 into Nb2O5 to form a heterojunction, creating a built-in electric field to enhance the migration and diffusion of Li+, effectively promoting electrochemical reaction kinetics. Under the regulation of the built-in electric field, the charge transfer resistance of the KCa2Nb3O10/Nb2O5 anode decreased by 3.4 times compared to pure Nb2O5, and the Li+ diffusion coefficient improved by two orders of magnitude. Specifically, the KCa2Nb3O10/Nb2O5 anode exhibited a high capacity of 276 mAh g−1 under 1 C, retaining a capacity of 128 mAh g−1 even at 100 C. After 3000 cycles at 25 C, the capacity degradation was only 0.012% per cycle. Through combined theoretical calculations and experimental validation, it was found that the built-in electric field induced by the heterojunction interface contributed to an asymmetric charge distribution, thereby improving the rates of charge and ion migration within the electrode, ultimately enhancing the electrochemical performance of the electrode material. This study provides an effective approach for the rational design of high-performance electrode materials.

Ion current rectification coupled with asymmetric temperature and surface charge in ultrashort conical nanopores

Ion current rectification (ICR) is one of the electrodynamic properties in asymmetric nanochannels, which has been utilized to develop biosensors, heavy metal ion detection, and ion diodes. Previous studies on ICR mainly focused on long nanopores (length >500 nm), and relatively few studies on ion rectification performance in short nanopores. Here, we use a finite element numerical solution to simulate the effect of coupling asymmetric temperature and surface charge distribution on the ion rectification performance of ultrashort conical nanopores (length = 100 nm). The results show that the ion rectification performance is significantly improved when the inner and outer surfaces of the nanopore are charged non-uniformly, which is more than three times that when the inner surface of the nanopore is charged non-uniformly or the outer surface is charged non-uniformly. In addition, the positive temperature difference enhances the ion enrichment and dissipation and improves the ion rectification performance of nanopores. On the contrary, negative temperature difference inhibits ion enrichment and dissipation in pores, which is not conducive to improving ion rectification performance. Abnormal behavior is observed for nanopores non-uniform charged only on the outer wall surface, where the negative temperature gradient enhances the accumulation and dissipation of ions within the pores, thereby increasing the rectification ratio. In addition, in order to more clearly understand the ion transport behavior in the ultrashort nanopore under asymmetric temperature conditions, we further investigated the influence of the tip radius of the nanopore, the solution volume concentration, and the charge type of each surface charge distribution on the ion current rectification performance. The results reveal the ion transport mechanism of ultrashort conical nanopores and provide practical guidance for designing and optimizing nanofluidic devices.

Built-in electric field construction and lattice oxygen activation for boosting alkaline electrochemical water/seawater oxidation

Oxygen evolution reaction (OER) remains a bottleneck for hydrogen production by water-alkali electrolysis at high industrial current density, but the structure–activity relationship of the catalyst and the underlying catalytic mechanism are still debated, which always limits the design of efficient catalysts. Herein, we report a proof-of-concept hierarchical hydroxide/sulfide (NiFe LDH/Ni3S2) heterostructure as model catalyst to simultaneously adjust the electronic states and activate lattice oxygen. As-activated NiFe LDH/Ni3S2 electrode displays promising OER capability with an ultra-low overpotential of 295 mV at the industrial current density of 500 mA·cm−2. The interface-induced built-in electric field effect promotes the asymmetric charge distribution on both sides. In-situ/ex-situ characterization demonstrates the adjusted intermediates adsorption/desorption and accelerated OER kinetics due to rapid electron transfer. A series of electrochemical probe experiments reveal that the OER mechanism of NiFe LDH/Ni3S2 follows the lattice oxygen mechanism. Especially, the super-strong wettability electrode design and structural advantages effectively enhance mass transfer and promote O2 desorption in alkaline water/seawater splitting systems. This work provides an avenue to break through OER limitations for efficient electrocatalytic water oxidation.

Asymmetric Atomic Dual-Sites for Photocatalytic CO2 Reduction.

Atomically dispersed active sites in a photocatalyst offer unique advantages such as locally tuned electronic structures, quantum size effects, and maximum utilization of atomic species. Among these, asymmetric atomic dual-sites are of particular interest because their asymmetric charge distribution generates a local built-in electric potential to enhance charge separation and transfer. Moreover, the dual sites provide flexibility for tuning complex multielectron and multireaction pathways, such as CO2 reduction reactions. The coordination of dual sites opens new possibilities for engineering the structure-activity-selectivity relationship. This comprehensive overview discusses efficient and sustainable photocatalysis processes in photocatalytic CO2 reduction, focusing on strategic active-site design and future challenges. It serves as a timely reference for the design and development of photocatalytic conversion processes, specifically exploring the utilization of asymmetric atomic dual-sites for complex photocatalytic conversion pathways, here exemplified by the conversion of CO2 into valuable chemicals.