Recent Advances in Direct Synthesis of Value‐Added Aromatic Chemicals from Syngas by Cascade Reactions over Bifunctional Catalysts

Value‐added aromatic monomers such as benzene, toluene, and xylenes (BTX) are very important building‐block chemicals for the production of plastics, polymers, solvents, pesticides, dyes, and adhesives. Syngas‐to‐aromatics (STA) is a very promising approach for the synthesis of aromatic monomers, and is catalyzed via bifunctional catalysts in a single reactor, wherein methanol/dimethyl ether and/or olefins intermediates formed from syngas on metal components are converted into aromatic monomers exclusively on the HZSM‐5 by cascade reactions. Since an optimal Fischer–Tropsch synthesis (FTS) temperature of Fe‐based catalysts is very close to an aromatization temperature of HZSM‐5, Fe‐based catalysts have been frequently used/modified for the synthesis of aromatic monomers from hydrogenation of carbon oxides (CO and CO₂). The nature of metal components and amounts of Brönsted acid sites on HZSM‐5, and their mesoporosity and intimacy, significantly alter the selectivity for aromatics by tuning BTX distibution and catalyst stability. Although many developments have been achieved regarding the STA process in recent years, no reviews have been published in this flourishing research area over the last two decades. Here, the recent advances and forthcoming challenges in the progress of syngas (CO+H₂) chemistry and hydrogenation of CO₂ toward the value‐added aromatic monomers through cascade reactions are highlighted.     

Single-atom catalysts with bimetallic centers for high-performance electrochemical CO2 reduction

The electrochemical CO₂ reduction reaction (CO₂RR) is a promising approach to alleviating global warming while concomitantly producing synthesis gas. Simultaneously achieving high current densities and tunable CO/H₂ (syngas) ratios remains a highly desired yet difficult challenge. Herein, we developed a 3D carbon-based material exhibiting bimetallic centers (NiNC and FeNC) with synergistic effects for the CO₂RR. The molar CO/H₂ ratio (∼1:3 to ∼4:1) was altered by varying the configuration structures of the metal-N sites and tuning the applied potential for industrial applications of syngas. Density functional theory calculations verified these experimental results. Additionally, varying the configuration structures of bimetallic centers changed the rate-limiting steps of FePc@NiNC(+0.95 eV), NiNC/FeNC (+1.25 eV) and NiPc@FeNC (+1.37 eV) for CO₂RR, while maintaining high catalytic activity with tunable syngas production. The reported materials system in this work represents a significant advancement of the CO₂RR towards practical applications.     

Reductive Transformation of Layered‐Double‐Hydroxide Nanosheets to Fe‐Based Heterostructures for Efficient Visible‐Light Photocatalytic Hydrogenation of CO

Conversion of syngas (CO, H₂) to hydrocarbons, commonly known as the Fischer–Tropsch (FT) synthesis, represents a fundamental pillar in today's chemical industry and is typically carried out under technically demanding conditions (1–3 MPa, 300–400 °C). Photocatalysis using sunlight offers an alternative and potentially more sustainable approach for the transformation of small molecules (H₂O, CO, CO₂, N₂, etc.) to high‐valuable products, including hydrocarbons. Herein, a novel series of Fe‐based heterostructured photocatalysts (Fe‐x) is successfully fabricated via H₂ reduction of ZnFeAl‐layered double hydroxide (LDH) nanosheets at temperatures (x) in the range 300–650 °C. At a reduction temperature of 500 °C, the heterostructured photocatalyst formed (Fe‐500) consists of Fe⁰ and FeO_x nanoparticles supported by ZnO and amorphous Al₂O₃. Fe‐500 demonstrates remarkable CO hydrogenation performance with very high initial selectivities toward hydrocarbons (89%) and especially light olefins (42%), and a very low selectivity towards CO₂ (11%). The intimate and abundant interfacial contacts between metallic Fe⁰ and FeO_x in the Fe‐500 photocatalyst underpins its outstanding photocatalytic performance. The photocatalytic production of high‐value light olefins with suppressed CO₂ selectivity from CO hydrogenation is demonstrated here.     

Synergistic Catalysis over Iron‐Nitrogen Sites Anchored with Cobalt Phthalocyanine for Efficient CO2 Electroreduction

Simultaneously achieving high Faradaic efficiency, current density, and stability at low overpotentials is essential for industrial applications of electrochemical CO₂ reduction reaction (CO₂RR). However, great challenges still remain in this catalytic process. Herein, a synergistic catalysis strategy is presented to improve CO₂RR performance by anchoring Fe‐N sites with cobalt phthalocyanine (denoted as CoPc©Fe‐N‐C). The potential window of CO Faradaic efficiency above 90% is significantly broadened from 0.18 V over Fe‐N‐C alone to 0.71 V over CoPc©Fe‐N‐C while the onset potential of CO₂RR over both catalysts is as low as ?0.13 V versus reversible hydrogen electrode. What is more, the maximum CO current density is increased ten times with significantly enhanced stability. Density functional theory calculations suggest that anchored cobalt phthalocyanine promotes the CO desorption and suppresses the competitive hydrogen evolution reaction over Fe‐N sites, while the *COOH formation remains almost unchanged, thus demonstrating unprecedented synergistic effect toward CO₂RR.     

Co‐Based Catalysts Derived from Layered‐Double‐Hydroxide Nanosheets for the Photothermal Production of Light Olefins

Solar‐driven Fischer–Tropsch synthesis represents an alternative and potentially low‐cost route for the direct production of light olefins from syngas (CO and H₂). Herein, a series of novel Co‐based photothermal catalysts with different chemical compositions are successfully fabricated by H₂ reduction of ZnCoAl‐layered double‐hydroxide nanosheets at 300–700 °C. Under UV–vis irradiation, the photothermal catalyst prepared at 450 °C demonstrates remarkable CO hydrogenation performance, affording an olefin (C_2–4⁼) selectivity of 36.0% and an olefin/paraffin ratio of 6.1 at a CO conversion of 15.4%. Characterization studies using X‐ray absorption fine structure and high‐resolution transmission electron microscopy reveal that the active catalyst comprises Co and Co₃O₄ nanoparticles on a ZnO–Al₂O₃ mixed metal oxide support. Density functional theory calculations further demonstrate that the oxide‐decorated metallic Co nanoparticle heterostructure weakens the further hydrogenation ability of the corresponding Co, leading to the high selectivity to light olefins. This study demonstrates a novel solar‐driven catalyst platform for the production of light olefins via CO hydrogenation.     

Electroreduction of Carbon Dioxide Driven by the Intrinsic Defects in the Carbon Plane of a Single Fe–N4 Site

Manipulating the in‐plane defects of metal–nitrogen–carbon catalysts to regulate the electroreduction reaction of CO₂ (CO₂RR) remains a challenging task. Here, it is demonstrated that the activity of the intrinsic carbon defects can be dramatically improved through coupling with single‐atom Fe–N₄ sites. The resulting catalyst delivers a maximum CO Faradaic efficiency of 90% and a CO partial current density of 33 mA cm^?2 in 0.1 m KHCO_3. The remarkable enhancements are maintained in concentrated electrolyte, endowing a rechargeable Zn–CO₂ battery with a high CO selectivity of 86.5% at 5 mA cm^?2. Further analysis suggests that the intrinsic defect is the active sites for CO₂RR, instead of the Fe–N₄ center. Density functional theory calculations reveal that the Fe–N₄ coupled intrinsic defect exhibits a reduced energy barrier for CO₂RR and suppresses the hydrogen evolution activity. The high intrinsic activity, coupled with fast electron‐transfer capability and abundant exposed active sites, induces excellent electrocatalytic performance.     

Highly Efficient Electroreduction of CO2 on Nickel Single‐Atom Catalysts: Atom Trapping and Nitrogen Anchoring

Construction of single atom catalysts (SACs) with high activity toward electroreduction of CO₂ still remains a great challenge. A very simple and truly cost‐effective synthetic strategy is proposed to prepare SACs via a impregnation–pyrolysis method, through one‐step pyrolysis of graphene oxide aerogel. Compared with other traditional methods, this process is fast and free of repeated acid etching, and thus it has great potential for facile operation and large‐scale manufacturing. Both X‐ray absorption fine structure and high‐angle annular dark‐field scanning transmission electron microscopy images confirm the presence of isolated nickel atoms, with a high Ni loading of ≈2.6 wt%. The obtained 3D porous Ni‐ and N‐codoped graphene aerogel exhibits excellent activity toward electroreduction of CO₂ to CO, in particular exhibiting a remarkable CO Faradaic efficiency of 90.2%. Density functional theory calculations reveal that free energies for the formation of intermediate *COOH on coordinatively unsaturated Ni? N sites are significantly lower than that on Ni? N₄ site, suggesting the outstanding activities of CO₂ electroreduction originate from coordinatively unsaturated Ni? N sites in catalysts.     

Metal–Organic‐Framework‐Based Catalysts for Photoreduction of CO2

Photoreduction of CO₂ into reusable carbon forms is considered as a promising approach to address the crisis of energy from fossil fuels and reduce excessive CO₂ emission. Recently, metal–organic frameworks (MOFs) have attracted much attention as CO₂ photoreduction‐related catalysts, owing to their unique electronic band structures, excellent CO₂ adsorption capacities, and tailorable light‐absorption abilities. Recent advances on the design, synthesis, and CO₂ reduction applications of MOF‐based photocatalysts are discussed here, beginning with the introduction of the characteristics of high‐efficiency photocatalysts and structural advantages of MOFs. The roles of MOFs in CO₂ photoreduction systems as photocatalysts, photocatalytic hosts, and cocatalysts are analyzed. Detailed discussions focus on two constituents of pure MOFs (metal clusters such as Ti–O, Zr–O, and Fe–O clusters and functional organic linkers such as amino‐modified, photosensitizer‐functionalized, and electron‐rich conjugated linkers) and three types of MOF‐based composites (metal–MOF, semiconductor–MOF, and photosensitizer–MOF composites). The constituents, CO₂ adsorption capacities, absorption edges, and photocatalytic activities of these photocatalysts are highlighted to provide fundamental guidance to rational design of efficient MOF‐based photocatalyst materials for CO₂ reduction. A perspective of future research directions, critical challenges to be met, and potential solutions in this research field concludes the discussion.     

Achieving the Widest Range of Syngas Proportions at High Current Density over Cadmium Sulfoselenide Nanorods in CO2 Electroreduction

Electroreduction of CO₂ is a sustainable approach to produce syngas with controllable ratios, which are required as specific reactants for the optimization of different industrial processes. However, it is challenging to achieve tunable syngas production with a wide ratio of CO/H₂, while maintaining a high current density. Herein, cadmium sulfoselenide (CdS_xSe_1?x) alloyed nanorods are developed, which enable the widest range of syngas proportions ever reported at the current density above 10 mA cm^?2 in CO₂ electroreduction. Among CdS_xSe_1?x nanorods, CdS nanorods exhibit the highest Faradaic efficiency (FE) of 81% for CO production with a current density of 27.1 mA cm^?2 at ?1.2 V vs. reversible hydrogen electrode. With the increase of Se content in CdS_xSe_1?x nanorods, the FE for H₂ production increases. At ?1.2 V vs. RHE, the ratios of CO/H₂ in products vary from 4:1 to 1:4 on CdS_xSe_1?x nanorods (x from 1 to 0). Notably, all proportions of syngas are achieved with current density higher than ≈25 mA cm^?2. Mechanistic study reveals that the increased Se content in CdS_xSe_1?x nanorods strengthens the binding of H atoms, resulting in the increased coverage of H* and thus the enhanced selectivity for H₂ production in CO₂ electroreduction.     

Hydration-Effect-Promoting Ni–Fe Oxyhydroxide Catalysts for Neutral Water Oxidation

Oxygen evolution reaction (OER) catalysts that function efficiently in pH-neutral electrolyte are of interest for biohybrid fuel and chemical production. The low concentration of reactant in neutral electrolyte mandates that OER catalysts provide both the water adsorption and dissociation steps. Here it is shown, using density functional theory simulations, that the addition of hydrated metal cations into a Ni–Fe framework contributes water adsorption functionality proximate to the active sites. Hydration-effect-promoting (HEP) metal cations such as Mg²⁺ and hydration-effect-limiting Ba²⁺ into Ni–Fe frameworks using a room-temperature sol–gel process are incorporated. The Ni–Fe–Mg catalysts exhibit an overpotential of 310 mV at 10 mA cm⁻² in pH-neutral electrolytes and thus outperform iridium oxide (IrO₂) electrocatalyst by a margin of 40 mV. The catalysts are stable over 900 h of continuous operation. Experimental studies and computational simulations reveal that HEP catalysts favor the molecular adsorption of water and its dissociation in pH-neutral electrolyte, indicating a strategy to enhance OER catalytic activity.     

Guest-Induced Multilevel Charge Transport Strategy for Developing Metal-Organic Frameworks to Boost Photocatalytic CO2 Reduction

Encapsulating photogenerated charge-hopping nodes and space transport bridges within metal–organic frameworks (MOFs) is a promising method of boosting the photocatalytic performance. Herein, this work embeds electron transfer media (9,10-bis(4-pyridyl)anthracene (BPAN)) in MOF cavities to build multi-level electron transfer paths. The MOF cavities are accurately regulated to investigate the significance of the multi-level electron transfer paths in the process of CO₂ photoreduction by evaluating the difference in the number of guest media. The prepared MOFs, {[Co(BPAN)(1,4-dicarboxybenzene)(H₂O)₂]·BPAN·2H₂O} and {[Co(BPAN)₂(4,4′-biphenyldicarboxylic acid)₂(H₂O)₂]·2BPAN·2H₂O} (denoted as BPAN-Co-1 and BPAN-Co-2), exhibit efficient visible-light-driven CO₂ conversion properties. The CO photoreduction efficacy of BPAN-Co-2 (5598 µmol g⁻¹ h⁻¹) is superior to that of most reported MOF-based catalysts. In addition, the enhanced CO₂ photoreduction ability is supported by density functional theory (DFT). This work illustrates the feasibility of realizing charge separation characteristics in MOF catalysts at the molecular level, and provides new insight for designing high-performance MOFs for artificial photosynthesis.     

Solar-CO2-to-Syngas Conversion Enabled by Precise Charge Transport Modulation

The rational design of the directional charge transfer channel represents an important strategy to finely tune the charge migration and separation in photocatalytic CO₂-to-fuel conversion. Despite the progress made in crafting high-performance photocatalysts, developing elegant photosystems with precisely modulated interfacial charge transfer feature remains a grand challenge. Here, a facile one-pot method is developed to achieve in situ self-assembly of Pd nanocrystals (NYs) on the transition metal chalcogenide (TMC) substrate with the aid of a non-conjugated insulating polymer, i.e., branched polyethylenimine (bPEI), for photoreduction of CO₂ to syngas (CO/H₂). The generic reducing capability of the abundant amine groups grafted on the molecular backbone of bPEI fosters the homogeneous growth of Pd NYs on the TMC framework. Intriguingly, the self-assembled TMCs@bPEI@Pd heterostructure with bi-directional spatial charge transport pathways exhibit significantly boosted photoactivity toward CO₂-to-syngas conversion under visible light irradiation, wherein bPEI serves as an efficient hole transfer mediator, and simultaneously Pd NYs act as an electron-withdrawing modulator for accelerating spatially vectorial charge separation. Furthermore, in-depth understanding of the in situ formed intermediates during the CO₂ photoreduction process are exquisitely probed. This work provides a quintessential paradigm for in situ construction of multi-component heterojunction photosystem for solar-to-fuel energy conversion.     

Hybridization of Defective Tin Disulfide Nanosheets and Silver Nanowires Enables Efficient Electrochemical Reduction of CO2 into Formate and Syngas

Integrating the defect engineering and conductivity promotion represents a promising way to improve the performance of CO₂ electrochemical reduction. Herein, the hybridized composite of defective SnS₂ nanosheets and Ag nanowires is developed as an efficient catalyst for the production of formate and syngas toward CO₂ electrochemical reduction. The Schottky barrier in Ag‐SnS₂ hybrid nanosheets is negligible due to the similar Fermi level of SnS₂ nanosheets and Ag nanowires. Accordingly, the free electrons of Ag nanowires participate in the electronic transport of SnS₂ nanosheets, and thus give rise to a 5.5‐fold larger carrier density of Ag‐SnS₂ hybrid nanosheets than that of SnS₂ nanosheets. In CO₂ electrochemical reduction, the Ag‐SnS₂ hybrid nanosheets display 38.8 mA cm^?2 of geometrical current density at –1.0 V vs reversible hydrogen electrode, including 23.3 mA cm^?2 for formate and 15.5 mA cm^?2 for syngas with the CO/H₂ ratio of 1:1. A mechanistic study reveals that the abundant defect sites and carrier density not only promote the conductivity of the electrocatalyst, but also increase the binding strength for CO₂, which account for the efficient CO₂ reduction.     

Toward Activity Origin of Electrocatalytic Hydrogen Evolution Reaction on Carbon‐Rich Crystalline Coordination Polymers

The fundamental understanding of electrocatalytic active sites for hydrogen evolution reaction (HER) is significantly important for the development of metal complex involved carbon electrocatalysts with low kinetic barrier. Here, the MS_x N_y (M = Fe, Co, and Ni, x /y are 2/2, 0/4, and 4/0, respectively) active centers are immobilized into ladder‐type, highly crystalline coordination polymers as model carbon‐rich electrocatalysts for H₂ generation in acid solution. The electrocatalytic HER tests reveal that the coordination of metal, sulfur, and nitrogen synergistically facilitates the hydrogen ad‐/desorption on MS_x N_y catalysts, leading to enhanced HER kinetics. Toward the activity origin of MS₂N₂, the experimental and theoretical results disclose that the metal atoms are preferentially protonated and then the production of H₂ is favored on the M? N active sites after a heterocoupling step involving a N‐bound proton and a metal‐bound hydride. Moreover, the tuning of the metal centers in MS₂N₂ leads to the HER performance in the order of FeS₂N₂ > CoS₂N₂ > NiS₂N₂. Thus, the understanding of the catalytic active sites provides strategies for the enhancement of the electrocatalytic activity by tailoring the ligands and metal centers to the desired function.     

A Highly Active Star Decahedron Cu Nanocatalyst for Hydrocarbon Production at Low Overpotentials

The electrochemical carbon dioxide reduction reaction (CO₂RR) presents a viable approach to recycle CO₂ gas into low carbon fuels. Thus, the development of highly active catalysts at low overpotential is desired for this reaction. Herein, a high‐yield synthesis of unique star decahedron Cu nanoparticles (SD‐Cu NPs) electrocatalysts, displaying twin boundaries (TBs) and multiple stacking faults, which lead to low overpotentials for methane (CH₄) and high efficiency for ethylene (C₂H₄) production, is reported. Particularly, SD‐Cu NPs show an onset potential for CH₄ production lower by 0.149 V than commercial Cu NPs. More impressively, SD‐Cu NPs demonstrate a faradaic efficiency of 52.43% ± 2.72% for C₂H₄ production at ?0.993 ± 0.0129 V. The results demonstrate that the surface stacking faults and twin defects increase CO binding energy, leading to the enhanced CO₂RR performance on SD‐Cu NPs.     

Semiconductor Quantum Dots: An Emerging Candidate for CO2 Photoreduction

As one of the most critical approaches to resolve the energy crisis and environmental concerns, carbon dioxide (CO₂) photoreduction into value‐added chemicals and solar fuels (for example, CO, HCOOH, CH₃OH, CH₄) has attracted more and more attention. In nature, photosynthetic organisms effectively convert CO₂ and H₂O to carbohydrates and oxygen (O₂) using sunlight, which has inspired the development of low‐cost, stable, and effective artificial photocatalysts for CO₂ photoreduction. Due to their low cost, facile synthesis, excellent light harvesting, multiple exciton generation, feasible charge‐carrier regulation, and abundant surface sites, semiconductor quantum dots (QDs) have recently been identified as one of the most promising materials for establishing highly efficient artificial photosystems. Recent advances in CO₂ photoreduction using semiconductor QDs are highlighted. First, the unique photophysical and structural properties of semiconductor QDs, which enable their versatile applications in solar energy conversion, are analyzed. Recent applications of QDs in photocatalytic CO₂ reduction are then introduced in three categories: binary II–VI semiconductor QDs (e.g., CdSe, CdS, and ZnSe), ternary I–III–VI semiconductor QDs (e.g., CuInS₂ and CuAlS₂), and perovskite‐type QDs (e.g., CsPbBr₃, CH₃NH₃PbBr₃, and Cs₂AgBiBr₆). Finally, the challenges and prospects in solar CO₂ reduction with QDs in the future are discussed.     

Carburization of Fe/Ni Catalyst for Efficient Growth of Single‐Walled Carbon Nanotubes

Scale‐up production of single‐walled carbon nanotubes (SWNTs) with high quality and purity is in pursuit, since the subsequent post purification treatment of residual metal or amorphous carbon is complicated and restricts further applications. Here, a compatible method to efficiently synthesize pure SWNTs on various supporters by using the precarburized Fe/Ni catalysts is reported. The preparation of catalysts is achieved by gas phase deposition together with CO gas at proper temperature, and the carburization of metal particles occurring simultaneously contributes to the size limitation of catalysts. By using micro‐quartz sand as a recyclable supporter, high‐quality SWNTs with a yield of 50 mg h^?1 are prepared with 60% metal precursor utilization, 81% carbon source utilization, and only 0.12% (m/m) metal residues. Taking advantage of carburized Fe/Ni catalysts and appropriate supports makes it possible to balance the quantity, purity, and quality among SWNTs growth. Furthermore, this method provides a straightforward pathway to strongly combine SWNTs and diverse composite materials for further potential applications.     

Photocatalytic CO<Subscript>2</Subscript> conversion over Au/TiO<Subscript>2</Subscript> nanostructures for dynamic production of clean fuels in a monolith photoreactor

Global economic development intensifies the consumption of fossil fuels which results in increase of carbon dioxide (CO₂) concentration in the atmosphere. The technologies for carbon capture and utilization to produce cleaner fuels are of great significance. However, phototechnology provides one perspective for economical CO₂ conversion to cleaner fuels. In this study, CO₂ conversion with H₂ to selective fuels over Au/TiO₂ nanostructures using environment friendly continuous monolith photoreactor has been investigated. Crystalline nanoparticles of anatase TiO₂ were obtained in the Au-doped TiO₂ samples. The Au deposited over TiO₂ in metal state produced plasmonic resonance. CO₂ was efficiently converted to CO as the main product over Au/TiO₂ with a maximum yield rate of 4144 µmol g-catal.^?1 h^?1, 345 fold-higher than using un-doped TiO₂ catalyst. The significantly enhanced photoactivity of Au/TiO₂ catalyst was due to hindered charges recombination rate and Au metallic-interband transition. The photon energy in the UV range was high enough to excite the d-band electronic transition in the Au to produce CO, CH₄, and C₂H₆. The quantum efficiency over Au/TiO₂ catalyst for CO was considerably improved in the continuous monolith photoreactor. At higher space velocity, the yield rates of CO gradually reduced, but the initial rates of hydrocarbon yields increased. The stability of the recycled Au/TiO₂ catalyst was sustained in cyclic runs. Thus, Au-doped TiO₂ supported over monolith channels is promising for enhanced CO₂ photoreduction to high energy products. This provides pathway that phototechnology to be explored further for cleaner and economical fuels production.     

Achieving Tunable Selectivity and Activity of CO2 Electroreduction to CO via Bimetallic Silver–Copper Electronic Engineering

Limited comprehension of the reaction mechanism has hindered the development of catalysts for CO₂ reduction reactions (CO₂RR). Here, the bimetallic AgCu nanocatalyst platform is employed to understand the effect of the electronic structure of catalysts on the selectivity and activity for CO₂ electroreduction to CO. The atomic arrangement and electronic state structure vary with the atomic ratio of Ag and Cu, enabling tunable d-band centers to optimize the binding strength of key intermediates. Density functional theory calculations confirm that the variation of Cu content greatly affects the free energy of *COOH, *CO (intermediate of CO), and *H (intermediates of H₂), which leads to the change of the rate-determining step. Specifically, Ag₉₆Cu₄ reduces the free energy of the formation of *COOH while maintaining a relatively high theoretical overpotential for hydrogen evolution reaction(HER), thus achieving the best CO selectivity. While Ag₇₀Cu₃₀ shows relatively low formation energy of both *COOH and *H, the compromised thermodynamic barrier and product selectivity allows Ag₇₀Cu₃₀ the best CO partial current density. This study realizes the regulation of the selectivity and activity of electrocatalytic CO₂ to CO, which provides a promising way to improve the intrinsic performance of CO₂RR on bimetallic AgCu.     

Highly Enhancing CO2 Photoreduction by Metallization of an Imidazole-linked Robust Covalent Organic Framework

Converting CO₂ into value-added chemicals to solve the issues caused by carbon emission is promising but challenging. Herein, by embedding metal ions (Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺) into an imidazole-linked robust photosensitive covalent organic framework (PyPor-COF), effective photocatalysts for CO₂ conversion are rationally designed and constructed. Characterizations display that all of the metallized PyPor-COFs (M-PyPor-COFs) display remarkably high enhancement in their photochemical properties. Photocatalysis reactions reveal that the Co-metallized PyPor-COF (Co-PyPor-COF) achieves a CO production rate as high as up to 9645 µmol g⁻¹ h⁻¹ with a selectivity of 96.7% under light irradiation, which is more than 45 times higher than that of the metal-free PyPor-COF, while Ni-metallized PyPor-COF (Ni-PyPor-COF) can further tandem catalyze the generated CO to CH₄ with a production rate of 463.2 µmol g⁻¹ h⁻¹. Experimental analyses and theory calculations reveal that their remarkable performance enhancement on CO₂ photoreduction should be attributed to the incorporated metal sites in the COF skeleton, which promotes the adsorption and activation of CO₂ and the desorption of generated CO and even reduces the reaction energy barrier for the formation of different intermediates. This work demonstrates that by metallizing photoactive COFs, effective photocatalysts for CO₂ conversion can be achieved.