Acidic electrocatalytic CO2 reduction to high-value multicarbon (C2+) products is an effective way to achieve high CO2 utilization, where a high concentration of K+ is necessary to suppress hydrogen evolution and promote C-C coupling. However, the high concentration of K+ often leads to salt precipitation, which compromises the stability of catalytic systems. Herein, we develop a K+ capture strategy to increase the local K+ concentration of the Cu nanosheet (CuNS) surface by modifying 4 '-aminobenzo-18-crown-6 (AB18C6), which serves as a trap to capture K+ via coordination and confinement. As a result, the modified CuNS achieves high-performance CO2 electroreduction in acid electrolyte with low concentration of K+. At a current density of-400 mA cm-2, the faraday efficiency of the C2+ products exceeds 82.3% with a single-pass carbon efficiency of 66.4%, much higher than that of pristine CuNS. Moreover, the constructed electrocatalytic CO2 reduction system can stably work for over 100 h. The results of in-situ spectro-electrochemical tests and density functional theory calculations reveal that the AB18C6 really enriches K+ on the CuNS, which facilitates C-C coupling by promoting CO2 activation and stabilizing *CO intermediates, thereby enabling the preferential conversion of CO2 to C2+ products.

Efficient adsorbents for organic dyes and iodine capture are critical to mitigate environmental hazards and safeguard public health. Herein, two structurally robust lanthanide MOFs (LCUH-126 and LCUH-127) were solvothermally synthesized with anthracene-based dicarboxylate ligands. Both samples adopt 2D layered structures, which further assemble into 3D supramolecular networks through intermolecular π···π stacking interactions of anthracene moieties, endowing the materials with prominent chemical and thermal stability. The large conjugated π-systems of anthracene together with interlayer -NH- groups endow the two MOFs with excellent adsorption capacity toward organic dyes and iodine. Abundant active sites originating from conjugated skeletons, -NH- moieties and coordinated solvent molecules strengthen the intermolecular interactions between iodine guests and the framework, affording high iodine vapor uptakes of 1.68 and 2.18 g/g at 80 °C. Appropriate interlayer spacing and hydrogen-bonding environments further favor the intercalation of dye molecules and the formation of weak intermolecular interactions. The two MOFs exhibit high adsorption capacities toward methylene blue (MB) and rhodamine B(RhB), and realize selective separation of mixed dye systems driven by electrostatic interaction and size matching. Combined with GCMC simulations, the adsorption mechanisms were elucidated. This work offers a rational strategy and theoretical basis for developing dual-functional adsorbents toward dye and iodine remediation.

Interfacial water structure critically affects the hydrogen evolution reaction (HER) in neutral and alkaline media, where sluggish water dissociation limits the Volmer step. Here, we report a distance-programmed metal-organic layer (MOLs) that is laid directly on metal electrode surfaces to regulate the near-surface microenvironment in HER. The vertical separation between the Hf6(μ3-O)4(μ3-OH)4 building units of the MOLs and the underlying metal surface can be systematically tuned by post-synthetic ligand exchange on the MOLs surface. Under operating conditions, deprotonation of μ3-OH on the Hf6(μ3-O)4(μ3-OH)4 cluster generates arrays of μ3-O− groups that can electrostatically enrich hydrated alkali cations at the metal-electrolyte interface. In situ Infrared spectroscopy showed that interfacial water reorganized after MOLs loading, from strongly hydrogen-bonded networks toward weakly bound, H-down configurations favorable for O–H bond cleavage. Shorter MOLs-metal distances markedly amplify this effect, leading to accelerated hydrogen evolution kinetics. On Pt electrodes, optimized spacing reduces the overpotential at 10 mA cm−2 by over 100 mV relative to bare metal. The enhancement persists across a broad pH range (3–9) and generalizes across multiple metal substrates, including Cu, Au, W, Co, and Ni. These results establish surface-laid, distance-defined MOLs as an interesting tool to study interfacial water structure and electrochemical kinetics through spatially programmed electrostatics.

This review summarizes the current research progress as well as challenges and future opportunities of newly emerging π frameworks in photocatalysis.

The performance of photocatalytic CO2 reduction is highly dependent on the electronic structures of active sites, while achieving delicate regulation of electronic states to enhance the catalytic performance remains challenging. Herein, we designed and synthesized four salen cobalt complexes with different functional groups in organic ligands (Co-X, X = -NO2, -COOMe, -tBu, and -OMe) for photocatalytic CO2 reduction. Impressively, by changing the -X groups of the organic ligands, the electronic structures of Co ions in Co-X can be regulated, which results in obviously different photocatalytic performance for the reduction of CO2 to CO, following the -X group sequence of -NO2 > -COOMe > -tBu > -OMe. The optimized Co-NO2 with the strongest electron-withdrawing ability of the -NO2 group achieves the largest turnover number (TON) and turnover frequency (TOF) values of 5727 and 0.32 s-1, respectively, 4.5 times higher than those of the Co-OMe. Theoretical calculations reveal that the spin populations of Co in Co-NO2 are the largest among the four cobalt complexes, which is the most beneficial for absorbing and activating the CO2 molecule, thereby accounting for its highest photocatalytic activity.

Developing highly efficient photocatalysts to achieve near-infrared (NIR) light-driven CO2 reduction is of great significance yet remains a great challenge. In this article, we found that BODIPY-based π frameworks can serve as good NIR photocatalysts, achieving highly efficient CO2 reduction to HCOO- coupled with benzyl alcohol oxidation to benzaldehyde in pure water. More impressively, the photocatalytic performance of these π frameworks can be improved by regulating π-π stacking interactions, among which the optimized π-pyrenyl (π-PY) framework with the most π-π stacking interactions exhibits HCOO- production rates of 4045 and 1693 µmol g-1 h-1 in >99% and 15% CO2 atmospheres, respectively. π-PY, thus, stands for the current state-of-the-art photocatalyst in NIR-light-driven CO2 reduction. Experiments together with theoretical calculations demonstrated that the high photocatalytic activity of π-PY could be due to the abundant π-π stacking interactions, which accelerates charge separation and transfer, as well as prolongs carrier lifetime and reduces energy gap. This work gives new insights in understanding the contribution of π-π stacking interactions to photocatalysis, and introduces a new strategy for developing efficient photocatalysts for NIR-light-driven CO2 reduction.

Metal-organic frameworks (MOFs) have sparked interest in photocatalysis. Unfortunately, they usually exhibit insufficient charge separation and catalytic efficiencies for artificial photosynthesis. Herein, the encapsulation of CsPbBr3 quantum dots (QDs) into the pores of dual-metal sites MOFs (MOF-919-Cu2M, M = Cu, Co, Zn) has been achieved to fabricate a series of CsPbBr3@MOF-919-Cu2M heterojunctions for CO2 photoreduction to HCOOH coupled with H2O oxidation to O-2. The close contact of CsPbBr3 QDs and MOF-919-Cu2M shortens the photo-induced electron transfer distance, which dramatically facilitates the charge separation. Meanwhile, the Cu and M dual-metal sites within the Cu2M clusters exhibit synergistic catalysis effect, which significantly enhances catalytic efficiency of active sites. As a result, CsPbBr3@MOF-919-Cu2Co achieves the highest photocatalytic performance with an electron consumption rate of 669.6 mu mol g(-1) h(-1) (selectivity, similar to 100 %) for HCOOH production, which is 64, 56 and 5 times higher than those of pristine CsPbBr3 QDs, MOF-919-Cu-3, and the physical mixture of CsPbBr3 QDs/MOF-919-Cu2Co, respectively. Experiments and theoretical calculations reveal that the Cu and Co dual-metal sites of CsPbBr3@MOF-919-Cu2Co show the optimal synergistic effect due to the strongest binding strength between Cu/Co and HCOO* intermediate, which can drastically decrease reaction energy barrier of the rate-determining step, thus explaining the enhanced photocatalytic activity.

The electrocatalytic carbon dioxide reduction reaction (CO2RR) provides a promising and feasible approach for utilizing CO2 as a resource and transforming the energy structure of the chemical industry. Compared with alkaline/neutral electrocatalytic systems, acidic environments not only effectively inhibit product crossover but also reduce the energy consumed for reactant regeneration. However, the dominant hydrogen evolution reaction (HER) and acid corrosion in an acidic solution seriously threaten the selectivity and stability of the CO2RR. To address these challenges, an efficient CO2RR can be achieved by regulating the mass transfer process and microenvironment through gas–solid–liquid three-phase interface engineering. This review summarizes the recent progress in acidic CO2RR research and focuses on optimization strategies for gas–liquid, gas–solid, and solid–liquid interfaces. We discuss the key challenges associated with each phase interface and outline innovative research directions to optimize the selectivity, activity, and stability of the acidic electrocatalytic CO2RR for industrial application.

Combining organic photosensitive center with dinuclear-metal catalytic center through covalent bonds to synthesize supramolecular catalysts for photocatalytic hydrogen evolution is a cost-efficient approach to convert solar to hydrogen energy, while it has been rarely explored. Herein, we constructed a self-photosensitizing pyrene-decorated dinuclear cobalt(II) molecular photocatalyst [Co2(pyrene-L)2] via covalent bonds, which can accelerate photogenerated electron transfer from pyrene center to dinuclear cobalt(II) center, achieving efficiently photocatalytic hydrogen evolution in the absence of any noble metal photosensitizers. The photocatalytic activity of Co2(pyrene-L)2 is more than 3-fold over that of the physically mixed sample. Moreover, owing to the synergistic effect of dinuclear cobalt(II) centers, the activity of Co2(pyrene-L)2 is 10-fold higher than that of mononuclear counterpart (Co(pyrene-L)2). As the first example of self-photosensitizing pyrene-decorated dinuclear metal molecular catalyst, it not only features multi-functions of photosensitivity, photoreduction and photooxidation, but also possesses synergistic dinuclear metal centers to improve catalytic activity, which gives new insights for researchers in designing high-performance photocatalysts for hydrogen evolution. (c) 2026, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

The direct electroreduction of CO2 at an electrolyte-free cathode to generate liquid chemical products with high concentration, selectivity and stability is highly desired, yet extremely challenging, and such systems are lacking. Here we report a high-flux membrane electrode assembly design that uses core-shell structural Cu/Bi nanowires grown on three-dimensional Cu foam with a mean pore size of 190 mu m (3D-Cu/Bi) as the cathode. Benefiting from the abundant active sites and high permeability of 3D-Cu/Bi, the catholyte-free membrane electrode assembly-based electrolyser can directly convert CO2 into formate with a high concentration of 4.5 M and maintain a high Faradaic efficiency of similar to 90% for 8,000 h at 200 mA cm(-2). We further demonstrate the continuous production of concentrated formate solution with a scaled-up 100 cm(2) electrolyser at 20 A for over 2,000 h.

Metal-coordinated covalent organic frameworks have attracted extensive attention in the field of CO2 photoreduction to CO due to their high electron affinity and tunable structure. However, achieving efficient CO2 activation requires overcoming the challenges of multi-electron transfer and intermediate stabilization, necessitating multifactorial optimization such as metal site cooperation, photosensitizer anchoring, and spatial alignment. Herein, we designed and fabricated a hydroxyl-functionalized COF featuring dinuclear Co/Zn sites and incorporated [Ru(phen)3](PF6)2 as the photosensitizer for photocatalytic reduction of CO2 to CO. When the ratio of Co(II) and Zn(II) in the dinuclear COF was 1:2, the obtained isostructural COF-Co1Zn2 showed enhanced CO production, with the CO conversion rate reached 46062 µmol g Co −1 h−1, which was three times higher than the CO production of the single metal COF (COF-Co: 15309 µmol g Co −1 h−1). DFT calculation and photoelectrochemical results supported the enhanced photocatalytic CO2 reduction performance of COF-Co1Zn2. This work shows that multi-site synergistic catalysis is an effective way to optimize the catalytic performance of COF catalysts for photochemical CO2 reduction.

With the escalating complexity of composite contamination in industrial wastewater, exploring high-efficiency and robust photocatalysts has become a research hotspot in environmental remediation. Herein, five isostructural rare-earth metal-organic frameworks (RE-MOFs, LCUH-128-132) were solvothermally assembled via the coordination of anthracene chromophore ligand 9,10-anthracenedicarboxylic acid (H2ADC) with five rare-earth metal ions (RE = Y, Eu, Gd, Tb, Dy). Remarkably, LCUH-129 (Eu-MOF) presents outstanding multifunctional photocatalytic activity without any additional photosensitizers or cocatalysts. It delivers a Cr(VI) reduction rate constant of 0.49 min-1, along with RhB and MB degradation rate constants of 0.23 min-1 and 0.026 min-1, respectively. The anthracene moiety serves as a light antenna to efficiently capture visible light; photogenerated electrons are rapidly transferred to rare-earth catalytic centers via ligand-to-metal charge transfer, which effectively inhibits electron-hole recombination. Radical trapping experiments and EPR characterization verify that ·OH, ·O2- radicals, and photogenerated electrons dominate the pollutant elimination processes. Furthermore, LCUH-129 exhibits excellent recyclability. This work affords a facile strategy for fabricating high-performance RE-MOF photocatalysts and reveals their promising prospects in the practical remediation of water composite pollution.

Semiconductor quantum dots (QDs) have emerged as promising materials for artificial photosynthesis, owing to their exceptional light-harvesting capabilities, efficient exciton generation, and tunable surface properties. However, challenges still remain in enhancing their solar-to-chemical conversion efficiency, reaction selectivity, long-term stability, and diversification of redox reactions. A promising strategy to address these limitations involves the precise confinement of QDs within porous matrices (either flexible or rigid frameworks), which offers new opportunities for advanced artificial photosynthetic systems. Furthermore, recent progress in nanomaterial synthesis and advanced characterization techniques has enabled innovative approaches for encapsulating QDs in porous matrices. This review systematically summarizes recent advancements in this field, covering fabrication strategies, charge carrier dynamics, and emerging functionalities. First, the predominant synthetic approaches is discussed, including "ship-in-a-bottle" and "bottle-around-the-ship" methods, along with the benefits and challenges of QD encapsulation in porous matrices. Next, key applications is highlighted, such as photocatalytic H2 evolution, CO2 photoreduction, and organic photoredox catalysis, providing mechanistic insights and performance comparisons. Finally, current challenges is outlined and future study directions to inspire the rational design of QD/porous material composites for large-scale, practical photochemical applications and beyond.

Hydrophilic-hydrophobic properties exert a vital influence on the reaction process of photocatalytic CO2 reduction. However, systematic study on revealing the relationship between photocatalytic activity and hydrophilicity-hydrophobicity has not been reported. Herein, based on covalent organic frameworks (COFs) with well-defined structures and structural tunability, we tentatively built the above relationship. Specifically, we designed and synthesized four isostructural COFs (Cu3–COOH–COF, Cu3–H–COF, Cu3–CH3–COF and Cu3–CF3–COF) with distinct hydrophilicity-hydrophobicity via Schiff base condensation reactions between trinuclear copper complex and p-phenylenediamine derivatives bearing different functional groups. We found that the most hydrophilic Cu3–COOH–COF achieved the highest photocatalytic activity for CO2 reduction, with the formic acid generation rate of 353.5 μmol g−1 h−1, 2.9, 4.7, and 6.0 folds over that of Cu3–H–COF, Cu3–CH3–COF, and Cu3–CF3–COF, respectively. Mechanistic studies demonstrate that enhanced hydrophilicity can optimize the interfacial wettability of the catalysts, accelerate interfacial electron transfer and proton transfer, and thereby significantly boost the photocatalytic activity for CO2 reduction. In contrast, hydrophobic catalysts impede the aforementioned processes, leading to a decline in catalytic performance. This study systematically uncovers the structure-activity relationship between the photocatalytic activity for CO2 reduction and the hydrophilic-hydrophobic properties of the catalyst.

Photocatalytic CO2 reduction represents a sustainable strategy to convert greenhouse gases into fuels and value‐added chemicals driven by solar energy, showing great potential for carbon recycling. However, the inherent inertness of CO2 poses a significant challenge to achieving efficient photocatalytic CO2 reduction. Among various catalysts, dinuclear metal catalysts (DMCs) have attracted increasing attention in this field owing to dinuclear metal synergistic catalysis (DMSC) effect, which can lower reaction energy barriers to enhance CO2 photoreduction activity. In this review, we summarize recent progress of molecule‐based DMCs in photocatalytic CO2 reduction, involving homogeneous molecule systems and corresponding heterogeneous composites integrating with crystalline framework materials or other semiconductors. This review centers on the construction strategies and synergistic catalytic mechanisms of DMC‐based catalytic systems. Further, we discuss the challenges and opportunities in this field, including the scalable preparation of DMC‐based catalysts and programmable improvement of activity, stability, and selectivity for photocatalytic CO2 reduction. These insights provide scientific guidance for the rational design of efficient DMCs and are expected to advance the development of carbon neutrality strategies.

Photocatalytic hydrogen evolution using solar energy is a promising approach for sustainable energy conversion, yet homogeneous metal cluster catalysts often suffer from instability and inefficient charge separation. Herein, we report a confinement strategy by embedding bimetallic trinuclear Fe2M (M = Co, Ni, Zn) clusters into a thiazole-based covalent organic framework (COF). The resulting COF@Fe2M hybrids combine the redox activity of metal clusters with the photoactive and porous architecture of COFs. Among them, COF@Fe2Co exhibits the highest activity, achieving 93.16 mmol g co −1 h−1 of H2 in a 10 h irradiation, 5.8 times that of the physical mixture. Spectroscopic and electrochemical studies reveal efficient interfacial charge transfer, while density functional theory (DFT) calculations show that the Fe2Co cluster has the most favorable electronic structure and hydrogen adsorption energy. This work offers a rational platform for designing efficient hybrid photocatalysts.

Activity-selectivity trade-off remains a grand challenge and crucial issue in artificial photosynthesis. As for the natural enzyme system, bimetallic clusters confined in protein-folding chains enable regulating the activity-selectivity equilibrium for photosynthesis. However, current artificial photocatalysts lack the precisely synergistic control over active site configuration and catalytic microenvironments, causing the compromised trade-off between activity and specificity. Herein, we developed a "ship-in-bottle" strategy to confine well-defined dual-metal-site pairs (DMSPs) Co2L2 in the cage of amino-functionalized metal-organic framework UiO-67-(NH2)2, aiming at synergistic regulation of selectivity and activity for photocatalytic CO2 reduction. The as-synthesized Co2L2@UiO-67-(NH2)2 realized the highest syngas yield with CO/H2 ≈ 1/1, whereas only H2 but no CO was detected for original Co2L2. It was demonstrated that the tailored microenvironment around DMSPs enhanced the specific adsorption of CO2 like that in enzymes. Furthermore, the electron consumption rate of Co2L2@UiO-67-(NH2)2 (11078.00 μmol·gDMSP-1·h-1) was 63-fold higher than that of the Co2L2+UiO-67-(NH2)2 physical mixture counterpart (174.30 μmol·gDMSP-1·h-1), ascribing to the synergistic catalytic effect of DMSPs and improved charge transfer. As a proof of concept, this work integrates dual-metal-site catalysts with local microenvironment engineering to suppress the kinetically favored hydrogen evolution pathway and accelerate the CO2 reduction reaction process, providing a novel and feasible approach for optimizing artificial photosynthesis.

H2O2 photosynthesis, as a gas-liquid-solid reaction, faces two giant challenges, i.e., charge recombination and sluggish oxygen transport. For improving efficiency, it is a feasible strategy to construct a robust triphase interface with optimized charge kinetics. Herein, we constructed a self-floating covalent-organic framework (COF)-based film with Janus heterostructure, i.e., COF-[NH2-GO]. In overall H2O2 photosynthesis, COF-[NH2-GO] exhibited the highest yield among COF film and powder, signifying improved separation and transfer of photogenerated carriers. The photocatalytic triphase system achieved 5,306.6 mu mol center dot m-2 center dot h-1 H2O2 yield, higher than that of diphase counterpart, ascribed to the promoted O2 delivery. It was demonstrated that excellent photocatalytic performance was attributed to the improved charge kinetics and mass transfer. A prototypical film-based device was designed for photosynthesis and collection of H2O2, which exhibited bactericidal activity against Escherichia coli. More importantly, this strategy could be extended to other COFs and functional nanomaterials. This work provides new insights for challenging triphase photocatalysis.

Capturing CO2 from natural gas and flue gas is of critical importance for energy conservation and achieving carbon-neutrality goals, yet it remains a significant challenge. Herein, we report two novel and stable 3D lanthanide MOFs, LCUH-123 and LCUH-124, which demonstrate remarkably selective CO2 adsorption over CH4 and N2, exhibiting excellent separation performance for both CO2/CH4 and CO2/N2 gas mixtures. LCUH-123's channel is obstructed by two coordinated DMF molecules, leading to near-complete blockage and a significantly reduced adsorption capacity. In contrast, LCUH-124's micropores are enriched with H2O-coordinated sites and free [(CH3)2NH2]+ cations, enabling superior gas adsorption and separation performance. Compared to LCUH-123, LCUH-124 exhibits significantly improved gas adsorption and separation performance, achieving higher selectivity coefficients for CO2/N2 and CO2/CH4 at zero coverage. Breakthrough experiments confirm that LCUH-124 serves as an efficient adsorbent for high-purity separation of CH4 and N2 from binary CO2/CH4 and CO2/N2 mixtures. Furthermore, its cost-effective synthetic process offers substantial economic advantages for large-scale applications. Theoretical calculations have elucidated the distinct adsorption and separation mechanisms of CO2/CH4 and CO2/N2 mixtures in LCUH-124. The exceptional performance of LCUH-124 stems from its rationally engineered pore architecture and cavity-directed coordination of water molecules with [NH2(CH3)2]+ cations within the channel.