Rechargeable Zn–CO2 Electrochemical Cells Mimicking Two‐Step Photosynthesis

Metal–CO₂ batteries represent a promising priority for sustainable energy and the environment. However, CO₂ utilization in nonaqueous electrolytes mostly involves difficult CO₂ electrochemistry, leading to poor selectivity and limited cycle performance. Herein, an aqueous rechargeable Zn–CO₂ electrochemical cell that tunably produced CO fuel gas (90% Faradaic efficiency) during cell discharge (cathodic reaction: CO₂ + 2e^? + 2H⁺ → CO + H₂O) and O₂ during cell charge at ≈2 V (cathodic reaction: H₂O → 1/2O₂ + 2e^? + 2H⁺), mimicking the separate steps of CO₂ fixation and water oxidation during photosynthesis while exhibiting the advantages of high efficiency, tunable products, and operation independent of sunlight is proposed and realized. The cell achieves a remarkable energy efficiency of 68% with fuel generation, providing an alternative for the green, efficient, and safe utilization of CO₂ by metal–CO₂ batteries.     

Grafting Hypercrosslinked Polymers on TiO2 Surface for Anchoring Ultrafine Pd Nanoparticles: Dramatically Enhanced Efficiency and Selectivity toward Photocatalytic Reduction of CO2 to CH4

Metal deposition with photocatalyst is a promising way to surmount the restriction of fast e^?/h⁺ recombination to improve the photocatalytic performance. However, the improvement remains limited by the existing strategies adopted for depositing metal particles due to the serious aggregation and large unconnected area on photocatalyst surface. Here, a strategy is proposed by directly grafting hypercrosslinked polymers (HCPs) on TiO₂ surface to construct Pd-HCPs-TiO₂ composite with uniform dispersion of ultrafine Pd nanoparticles on HCPs surface. This composite with surface area of 373 m² g^?1 exhibits improved photocatalytic CO₂ conversion efficiency to CH₄ with an evolution rate of 237.4 µmol g^?1 h^?1 and selectivity of more than 99.9%. The enhancement can be ascribed to the grafted porous HCPs with high surface area and N heteroatom on TiO₂ surface for the stabilization of Pd nanoparticles, favoring the electron transfer and CO₂ adsorption for selective CH₄ production. This strategy may hold the promise for design and construction of porous organic polymer with semiconductor for efficient photocatalytic conversion.     

Atomically Dispersed Electron Traps in Cu Doped BiOBr Boosting CO2 Reduction to Methanol by Pure H2O

Overall photocatalytic conversion of CO₂ and pure H₂O driven by solar irradiation into methanol provides a sustainable approach for extraterrestrial synthesis. However, few photocatalysts exhibit efficient production of CH₃OH. Here, BiOBr nanosheets supporting atomic Cu catalysts for CO₂ reduction are reported. The investigation of charge dynamics demonstrates a strong built-in electric field established by isolated Cu sites as electron traps to facilitate charge transfer and stabilize charge carriers. As result, the catalysts exhibit a substantially high catalytic performance with methanol productivity of 627.66 µmol g_catal⁻¹ h⁻¹ and selectivity of ≈90% with an apparent quantum efficiency of 12.23%. Mechanism studies reveal that the high selectivity of methanol can be ascribed to energy-favorable hydrogenation of *CO intermediate giving rise to *CHO. The unfavorable adsorption on Cu₁@BiOBr prevents methanol from being oxidized by photogenerated holes. This work highlights the great potential of single-atom photocatalysts in chemical transformation and energy storage reactions.     

Facile preparation of porous carbon nitride for visible light photocatalytic reduction and oxidation applications

In this work, we have employed melamine, cyanuric acid and thymine to fabricate triazine-based carbon nitrides (CNs) by supramolecular approach. The resultant CNs possess large specific surface area, hierarchical porous structure, better light absorption capacity and high separation rate of photoinduced carriers. Then, the photocatalytic reduction and oxidation performance has been evaluated. The obtained CNs exhibit enhanced photocatalytic reduction performance on water splitting to H₂, the largest hydrogen evolution rate can reach 8466.3 μmol g^?1 h^?1, which is 81.9 times as high as that of bulk CN. Simultaneously, the porous CNs show excellent photocatalytic reduction ability on the conversion of CO₂ to H₂, CO and CH₄. Of particular interest is that they have high selectivity for CO. It’s worth noting that the porous CNs also possess outstanding photocatalytic oxidation ability on high concentration nitric oxide (NO), and the highest NO conversion rate can reach 79.3% under visible light. The enhanced photocatalytic performance for the multifunctional porous CN can be ascribed to the synergic effect of large specific surface area, strong light absorption capacity and fast separation of photoinduced electron–hole pairs. Finally, the photocatalytic reduction and oxidation mechanism of the porous CN is also proposed and discussed.     

Advanced Catalyst for CO2 Photo-Reduction: From Controllable Product Selectivity by Architecture Engineering to Improving Charge Transfer Using Stabilized Au Clusters

Despite enormous progress and improvement in photocatalytic CO₂ reduction reaction (CO₂RR), the development of photocatalysts that suppress H₂ evolution reaction (HER), during CO₂RR, remains still a challenge. Here, new insight is presented for controllable CO₂RR selectivity by tuning the architecture of the photocatalyst. Au/carbon nitride with planar structure (p Au/CN) showed high activity for HER with 87% selectivity. In contrast, the same composition with a yolk@shell structure (Y@S Au@CN) exhibited high selectivity of carbon products by suppressing the HER to 26% under visible light irradiation. Further improvement for CO₂RR activity was achieved by a surface decoration of the yolk@shell structure with Au₂₅(PET)₁₈ clusters as favorable electron acceptors, resulting in longer charge separation in Au@CN/Au_c Y@S structure. Finally, by covering the structure with graphene layers, the designed catalyst maintained high photostability during light illumination and showed high photocatalytic efficiency. The optimized Au@CN/Au_c/G Y@S structure displays high photocatalytic CO₂RR selectivity of 88%, where the CO and CH₄ generations during 8 h are 494 and 198 µmol/gcat., respectively. This approach combining architecture engineering and composition modification provides a new strategy with improved activity and controllable selectivity toward targeting applications in energy conversion catalysis.     

A Hierarchical Z‐Scheme CdS–WO3 Photocatalyst with Enhanced CO2 Reduction Activity

The development of an artificial photosynthetic system is a promising strategy to convert solar energy into chemical fuels. Here, a direct Z‐scheme CdS–WO₃ photocatalyst without an electron mediator is fabricated by imitating natural photosynthesis of green plants. Photocatalytic activities of as‐prepared samples are evaluated on the basis of photocatalytic CO₂ reduction to form CH₄ under visible light irradiation. These Z‐scheme‐heterostructured samples show a higher photocatalytic CO₂ reduction than single‐phase photocatalysts. An optimized CdS–WO₃ heterostructure sample exhibits the highest CH₄ production rate of 1.02 μmol h^?1 g^?1 with 5 mol% CdS content, which exceeds the rates observed in single‐phase WO₃ and CdS samples for approximately 100 and ten times under the same reaction condition, respectively. The enhanced photocatalytic activity could be attributed to the formation of a hierarchical direct Z‐scheme CdS–WO₃ photocatalyst, resulting in an efficient spatial separation of photo‐induced electron–hole pairs. Reduction and oxidation catalytic centers are maintained in two different regions to minimize undesirable back reactions of the photocatalytic products. The introduction of CdS can enhance CO₂ molecule adsorption, thereby accelerating photocatalytic CO₂ reduction to CH₄. This study provides novel insights into the design and fabrication of high‐performance artificial Z‐scheme photocatalysts to perform photocatalytic CO₂ reduction.     

Ceo2/Cus Nanoplates Electroreduce Co2 to Ethanol with Stabilized Cu+ Species

Copper-based electrocatalysts effectively produce multicarbon (C₂₊) compounds during the electrochemical CO₂ reduction (CO₂RR). However, big challenges still remain because of the chemically unstable active sites. Here, cerium is used as a self-sacrificing agent to stabilize the Cu⁺ of CuS, due to the facile Ce³⁺/Ce⁴⁺ redox. CeO₂-modified CuS nanoplates achieve high ethanol selectivity, with FE up to 54% and FE_C2+ ≈ 75% in a flow cell. Moreover, in situ Raman spectroscopy and in situ Fourier-transform infrared spectroscopy indicate that the stable Cu⁺ species promote C C coupling step under CO₂RR. Density functional theory calculations further reveal that the stronger ^*CO adsorption and lower C C coupling energy, which is conducive to the selective generation of ethanol products. This work provides a facile strategy to convert CO₂ into ethanol by retaining Cu⁺ species.     

Boron Phosphide Nanoparticles: A Nonmetal Catalyst for High‐Selectivity Electrochemical Reduction of CO2 to CH3OH

Electrocatalysis has emerged as an attractive way for artificial CO₂ fixation to CH₃OH, but the design and development of metal‐free electrocatalyst for highly selective CH₃OH formation still remains a key challenge. Here, it is demonstrated that boron phosphide nanoparticles perform highly efficiently as a nonmetal electrocatalyst toward electrochemical reduction of CO₂ to CH₃OH with high selectivity. In 0.1 m KHCO₃, this catalyst achieves a high Faradaic efficiency of 92.0% for CH₃OH at ?0.5 V versus reversible hydrogen electrode. Density functional theory calculations reveal that B and P synergistically promote the binding and activation of CO₂, and the rate‐determining step for the CO₂ reduction reaction is dominated by *CO + *OH to *CO + *H₂O process with free energy change of 1.36 eV. In addition, CO and CH₂O products are difficultly generated on BP (111) surface, which is responsible for the high activity and selectivity of the CO₂‐to‐CH₃OH conversion process.     

Cu?C(O) Interfaces Deliver Remarkable Selectivity and Stability for CO2 Reduction to C2+ Products at Industrial Current Density of 500 mA cm−2

The electrocatalytic CO₂ reduction reaction (CO₂RR) is an attractive technology for CO₂ valorization and high-density electrical energy storage. Achieving a high selectivity to C₂₊ products, especially ethylene, during CO₂RR at high current densities (>500 mA cm⁻²) is a prized goal of current research, though remains technically very challenging. Herein, it is demonstrated that the surface and interfacial structures of Cu catalysts, and the solid–gas–liquid interfaces on gas-diffusion electrode (GDE) in CO₂ reduction flow cells can be modulated to allow efficient CO₂RR to C₂₊ products. This approach uses the in situ electrochemical reduction of a CuO nanosheet/graphene oxide dots (CuO C(O)) hybrid. Owing to abundant Cu O C interfaces in the CuO C(O) hybrid, the CuO nanosheets are topologically and selectively transformed into metallic Cu nanosheets exposing Cu(100) facets, Cu(110) facets, Cu[n(100) × (110)] step sites, and Cu⁺/Cu⁰ interfaces during the electroreduction step,  the faradaic efficiencie (FE) to C₂₊ hydrocarbons was reached as high as 77.4% (FE_ethylene ≈ 60%) at 500 mA cm⁻² . In situ infrared spectroscopy and DFT simulations demonstrate that abundant Cu⁺ species and Cu⁰/Cu⁺ interfaces in the reduced CuO C(O) catalyst improve the adsorption and surface coverage of *CO on the Cu catalyst, thus facilitating C C coupling reactions.     

Continuously Flow Photothermal Catalysis Efficiently CO2 Reduction Over S-Scheme 2D/0D Bi5O7I-OVs/Cd0.5Zn0.5S Heterojunction with Strong Interfacial Electric Field

Using CO₂, water, and sunlight to produce solar fuel is a very attractive process, which can synchronously reduce carbon and convert solar energy into hydrocarbons. However, photocatalytic CO₂ reduction is often limited by the low selectivity of reduction products and poor photocatalytic activity. In this study, S-scheme Bi₅O₇I-OVs/Cd_0.5Zn_0.5S (Bi₅O₇I-OVs/CZS-0.5) heterojunction with strong interfacial electric field (IEF) is prepared by in situ growth method. The performance of reduction CO₂ to CO is studied by continuous flow photothermal catalytic (PTC) CO₂ reduction platform. 12.5% Bi₅O₇I-OVs/CZS-0.5 shows excellent CO yield of 58.6 µmol g⁻¹ h⁻¹ and selectivity of 98.4%, which are 35.1 times than that of CZS-0.5 under visible light. The charge transfer path of the S-scheme through theoretical calculation (DFT), in situ irradiation Kelvin probe force microscope (ISI-KPFM) and in situ irradiation X-ray photoelectron spectroscopy (ISI-XPS) analysis, is verified. The study can provide useful guidance and reference for improving activity by oxygen vacancy induced strong IEF and the development of a continuous flow PTC CO₂ reduction system.     

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.     

Photocatalytic reduction of CO<Subscript>2</Subscript> with H<Subscript>2</Subscript>O over modified TiO<Subscript>2</Subscript> nanofibers: Understanding the reduction pathway

Nanosized metal (Pt or Pd)-decorated TiO₂ nanofibers (NFs) were synthesized by a wet impregnation method. CdSe quantum dots (QDs) were then anchored onto the metal-decorated TiO₂ NFs. The photocatalytic performance of these catalysts was tested for activation and reduction of CO₂ under UV-B light. Gas chromatographic analysis indicated the formation of methanol, formic acid, and methyl formate as the primary products. In the absence of CdSe QDs, Pd-decorated TiO₂ NFs were found to exhibit enhanced performance compared to Pt-decorated TiO₂ NFs for methanol production. However, in the presence of CdSe, Pt-decorated TiO₂ NFs exhibited higher selectivity for methanol, typically producing ～90 ppmg^?1·h^?1 methanol. The CO₂ photoreduction mechanism is proposed to take place via a hydrogenation pathway from first principles calculations, which complement the experimental observations.

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Hybrid Cu0 and Cux+ as Atomic Interfaces Promote High‐Selectivity Conversion of CO2 to C2H5OH at Low Potential

The mixing of charge states of metal copper catalysts may lead to a much improved reactivity and selectivity toward multicarbon products for CO₂ reduction. Here, an electrocatalyst model composed of copper clusters supported on graphitic carbon nitride (g‐C₃N₄) is proposed; the connecting Cu atoms with g‐C₃N₄ can be oxidized to Cu^{x +} due to substantial charge transfer from Cu to N atoms, while others stay as Cu⁰. It is revealed that CO₂ can be captured and reduced into *CO on the Cu_t⁰ site, owing to its zero oxidation state. More importantly, C–C coupling reaction of two *CHO species on the Cu_t⁰–Cu_b^{x +} atomic interface can occur with a rather low kinetic barrier of 0.57 eV, leading to the formation of the final C₂ product, namely, C₂H₅OH. During the whole process, the limiting potential is just 0.68 V. These findings may open a new avenue for CO₂ reduction into high‐value fuels and chemicals.     

A simple ultrasono-synthetic route of PbSe-graphene-TiO2 ternary composites to improve the photocatalytic reduction of CO2

The present work investigates the photocatalytic reduction of CO₂ to CH₃OH with a PbSe-G-TiO₂ photocatalyst. A heterogeneous PbSe-G-TiO₂ nanocomposite was prepared via ultra-sonication and was characterized via XRD, SEM, HRTEM, Raman, XPS, and DRS measurements. The photocatalytic efficiencies of the prepared sample were further characterized by GC for the photoreduction of CO₂ to CH₃OH under UV and visible light. The prepared PbSe-G-TiO₂ ternary nanocomposites with an optimum GO loading of 6% exhibited outstanding photocatalytic activity (4.35 µmol g^?1 h^?1) after 48 hours of reaction. This indicated that the photocatalytic efficiency was mostly dependent on the weight ratio of graphene, sacrificial material Na₂SO₃/Na₂S, and the type of reactant. This work provides an accessible way to improve the response of a graphene-based TiO₂ photocatalyst to UV/visible light and to facilitate its application in environmental remediation.     

A Hierarchical Z‑Scheme α‐Fe2O3/g‐C3N4 Hybrid for Enhanced Photocatalytic CO2 Reduction

The challenge in the artificial photosynthesis of fossil resources from CO₂ by utilizing solar energy is to achieve stable photocatalysts with effective CO₂ adsorption capacity and high charge‐separation efficiency. A hierarchical direct Z‐scheme system consisting of urchin‐like hematite and carbon nitride provides an enhanced photocatalytic activity of reduction of CO₂ to CO, yielding a CO evolution rate of 27.2 µmol g^?1 h^?1 without cocatalyst and sacrifice reagent, which is >2.2 times higher than that produced by g‐C₃N₄ alone (10.3 µmol g^?1 h^?1). The enhanced photocatalytic activity of the Z‐scheme hybrid material can be ascribed to its unique characteristics to accelerate the reduction process, including: (i) 3D hierarchical structure of urchin‐like hematite and preferable basic sites which promotes the CO₂ adsorption, and (ii) the unique Z‐scheme feature efficiently promotes the separation of the electron–hole pairs and enhances the reducibility of electrons in the conduction band of the g‐C₃N₄. The origin of such an obvious advantage of the hierarchical Z‐scheme is not only explained based on the experimental data but also investigated by modeling CO₂ adsorption and CO adsorption on the three different atomic‐scale surfaces via density functional theory calculation. The study creates new opportunities for hierarchical hematite and other metal‐oxide‐based Z‐scheme system for solar fuel generation.     

Acid and Base Resistant Zirconium Polyphenolate‐Metalloporphyrin Scaffolds for Efficient CO2 Photoreduction

A series of zirconium polyphenolate‐decorated‐(metallo)porphyrin metal–organic frameworks (MOFs), ZrPP‐n (n = 1, 2), featuring infinite Zr^IV‐oxo chains linked via polyphenolate groups on four peripheries of eclipse‐arranged porphyrin macrocycles, are successfully constructed through a top–down process from simulation to synthesis. These are the unusual examples of Zr‐MOFs (or MOFs in general) based on phenolic porphyrins, instead of commonly known carboxylate‐based types. Representative ZrPP‐1 not only exhibits strong acid resistance (pH = 1, HCl) but also remains intact even when immersed in saturated NaOH solution (≈20 m ), an exceptionally large range of pH resistance among MOFs. The metallation at the porphyrin core gives rise to materials with enhanced sorption and catalytic properties. In particular, ZrPP‐1‐Co, with precise and uniform distribution of active centers, exhibits not only high CO₂ trapping capability (≈90 cm³ g^?1 at 1 atm, 273 K, among the highest in Zr‐MOFs) but also high photocatalytic activity for reduction of CO₂ into CO (≈14 mmol g^?1 h^?1) and high selectivity over CH₄ (>96.4%) without any cocatalyst under visible‐light irradiation (λ > 420 nm). Given the strong chemical resistance under extreme alkali conditions, these catalysts can be recycled without appreciable loss of activity. The possible mechanism for photocatalytic reduction of CO₂‐to‐CO over ZrPP‐1‐Co is also proposed.     

Highly efficient nanostructured metal-decorated hybrid semiconductors for solar conversion of CO2 with almost complete CO selectivity

Photocatalytic reduction of CO₂ into solar fuels is regarded as a promising method to address global warming and energy crisis problems. Although heterostructured hybrid metal oxide catalysts have been used for CO₂ reduction, selective control for CO production-only remains the subject of debate. In this paper, we report an absolute selectivity for CO production-only with enhanced photocatalytic ability using Ag-decorated reduced titanium oxide/tungsten hybrid nanoparticles (blue TiO₂/WO₃–Ag HNPs) at 1166.72 μmol g⁻¹ h⁻¹ with an apparent quantum yield of 34.8%. The construction of a Z-scheme between blue TiO₂ and WO₃ domains with an excellent band alignment provided remarkably improved separation of photoinduced charges. Importantly, the presence of novel Ag not only produces the highest selectivity up to 100% CO production-only, but also increases the photocatalytic electron reaction rate (2333.44 μmol g⁻¹ h⁻¹).     

Enhanced the Efficiency of Electrocatalytic CO2-to-CO Conversion by Cd Species Anchored into Metal-Organic Framework

Metal-organic frameworks (MOFs) as a promising platform for electrocatalytic CO₂ conversion are still restricted by the low efficiency or unsatisfied selectivity for desired products. Herein, zirconium-based porphyrinic MOF hollow nanotubes with Cd sites (Cd-PCN-222HTs) are reported for electrocatalytic CO₂-to-CO conversion. The dispersed Cd species are anchored in PCN-222HTs and coordinated by N atoms of porphyrin structures. It is discovered that Cd-PCN-222HTs have glorious electrocatalytic activity for selective CO production in ionic liquid-water (H₂O)-acetonitrile (MeCN) electrolyte. The CO Faradaic efficiency (FE_CO) of >80% could be maintained in a wide potential range from −2.0 to −2.4 V versus Ag/Ag⁺, and the maximum current density could reach 68.0 mA cm⁻² at −2.4 V versus Ag/Ag⁺ with a satisfied turnover frequency of 26 220 h⁻¹. The enhanced efficiency of electrocatalytic CO₂ conversion of Cd-PCN-222HTs is closely related to its hollow structure, anchored Cd species, and good synergistic effect with electrolyte. The density functional theory calculations indicate that the dispersed Cd sites anchored in PCN-222HTs not only favor the formation of *COOH intermediate but also hinder the hydrogen evolution reaction, resulting in high activity of electrocatalytic CO₂-to-CO conversion.     

Engineering Single Cu Sites into Covalent Organic Framework for Selective Photocatalytic CO2 Reduction

Photocatalytic CO₂ conversion into value-added chemicals is a promising route but remains challenging due to poor product selectivity. Covalent organic frameworks (COFs) as an emerging class of porous materials are considered as promising candidates for photocatalysis. Incorporating metallic sites into COF is a successful strategy to realize high photocatalytic activities. Herein, 2,2′-bipyridine-based COF bearing non-noble single Cu sites is fabricated by chelating coordination of dipyridyl units for photocatalytic CO₂ reduction. The coordinated single Cu sites not only significantly enhance light harvesting and accelerate electron–hole separation but also provide adsorption and activation sites for CO₂ molecules. As a proof of concept, the Cu-Bpy-COF as a representative catalyst exhibits superior photocatalytic activity for reducing CO₂ to CO and CH₄ without photosensitizer, and impressively, the product selectivity of CO and CH₄ can be readily modulated only by changing reaction media. Experimental and theoretical results reveal the crucial role of single Cu sites in promoting photoinduced charge separation and solvent effect in regulating product selectivity, which provides an important sight onto the design of COF photocatalysts for selective CO₂ photoreduction.     

The effects of morphologies on photoreduction of carbon dioxide to gaseous fuel over tin disulfide under visible light irradiation

Artificial photosynthesis has attracted a lot of attention because it can tackle both global environmental problems and energy crisis. In this paper, SnS₂ with different morphologies were synthesized to study their activity and selectivity of photocatalytic reduction of carbon dioxide (CO₂). The size of tablet-like SnS₂ is around 80–120 nm while the flower-like SnS₂ is composed of nanosheets with a thickness of 10 nm. The reduction products of the as-obtained samples are both CO and CH₄. The flower-like SnS₂ sample processes more efficacious separation of photogenerated carriers compared to tablet-like SnS₂ and shows higher photocatalytic reduction efficiency with CH₄ yield of 97.5 μmol g⁻¹, which is approximately 5.7 times higher than that of tablet-like SnS₂, while the tablet-like SnS₂ shows high selectivity (79%) for CO production. The results reveal that the morphology plays an important role in the activity and selectivity of photocatalytic reduction of CO₂ over SnS₂.