Enhanced CO2 Adsorption Research Articles

A Highly Conjugated Nickel(II)‐Acetylide Framework for Efficient Photocatalytic Carbon Dioxide Reduction

AbstractThe incorporation of transition‐metal single atoms as molecular functional entities into the skeleton of graphdiyne (GDY) to construct novel two‐dimensional (2D) metal‐acetylide frameworks, known as metalated graphynes (MGYs), is a promising strategy for developing efficient catalysts, which can combine the tunable charge transfer of GDY frameworks, the catalytic activity of metal and the precise distribution of single metallic centers. Herein, four highly conjugated MGY photocatalysts based on NiII, PdII, PtII, and HgII were synthesized for the first time using the ‘bottom‐up’ strategy through the use of M−C bonds (−C≡C−M−C≡C−). Remarkably, the NiII‐based graphyne (TEPY‐Ni‐GY) exhibited the highest CO generation rate of 18.3 mmol g−1 h−1 and a selectivity of 98.8 %. This superior performance is attributed to the synergistic effects of pyrenyl and −C≡C−Ni(PBu3)2−C≡C– moieties. The pyrenyl block functions as an intramolecular π‐conjugation channel, facilitating kinetically favorable electron transfer, while the −C≡C−Ni(PBu3)2−C≡C− moiety serves as the catalytic site that enhances CO2 adsorption and activation, thereby suppressing competitive hydrogen evolution. This study provides a new perspective on MGY‐based photocatalysts for developing highly active and low‐cost catalysts for CO2 reduction.

Constructing an Active Sulfur-Vacancy-Rich Surface for Selective *CH3-CH3 Coupling in CO2-to-C2H6 Conversion With 92% Selectivity.

To achieve high selectivity in photocatalytic CO2 reduction to C2+ products, increasing the number of CO2 adsorption sites and lowering the energy barriers for key intermediates are critical. A ZnIn2S4 (ZIS)/MoO3-x (Z-M) photocatalyst is presented, in which plasmonic MoO3-x generates hot electrons, creating a multielectron environment in ZIS that facilitates efficient C─C coupling reactions. Density functional theory (DFT) calculations reveal that MoO3-x reduces the formation energy of sulfur vacancies (SV) in ZIS, thereby enhancing CO2 adsorption and activation. The SV-rich surface lowers the energy barrier for forming HCOO* to -0.33 eV whereas the energy barrier for forming *COOH is 0.77 eV. Successive hydrogenation of HCOO* leads to *CH2, which converts to *CH3 with an energy barrier of -0.63 eV. The energy barrier for *CH3-CH3 coupling is 0.54 eV, which is lower than the 0.73 eV for *CH2-CH2 coupling to form *C2H4. Thus, Z-M preferentially produces C2H6 over C2H4. Under visible light, Z-M achieves a CO2-to-C2H6 conversion rate of 467.3 µmol g-1 h-1 with 92.0% selectivity. This work highlights the dual role of plasmonic photocatalysts in enhancing CO2 adsorption and improving C2+ production in CO2 reduction.

Engineering Co Single Atoms in Ultrathin BiOCl Nanosheets for Boosted CO2 Photoreduction

AbstractDespite the development of a range of photocatalysts for CO2 reduction, the practical applications are significantly limited by low conversion efficiencies and their reliance on sacrificial agents, which are rooted in thermodynamic and kinetic challenges related to CO2 conversion. Here, the engineering of Co single atoms in ultrathin single‐crystal BiOCl nanosheets for boosted photocatalytic CO2 reduction is reported. The engineering of Co atoms modulates the distribution of photogenerated charges at the catalyst surface, controlling key surface reaction dynamics and suppressing surface electron‐hole recombination. This modulation also improves light absorption and enhances CO2 adsorption and activation, leading to more efficient surface reactions. Notably, CO2 is stably adsorbed onto the (001) face of BiOCl through a Bi‐O‐C(= O)‐Co‐O coordination unit, which lowers the activation energy for CO2 reduction and reduces the formation energy of COOH− intermediates. As a result, the BiOCl photocatalysts achieve a CO formation rate of 183.9 µmol g−1 h−1, when irradiated with a 300 W Xe lamp without cocatalysts or sacrificial agents. It represents an ≈13‐fold increase compared to that of pristine BiOCl, and surpasses most reported Bi‐based photocatalysts to date. Current work provides valuable insights into engineering of single atoms for developing advanced CO2‐reduction photocatalysts.

Enhancement of CO2 adsorption and oxygen transfer properties on γ-Al2O3 support through surface modification with MgO-ZrO2 for coke suppression over Ni catalyst in CO2 reforming of methane

This work focuses on employing commercial γ-Al2O3 for surface modification with MgO-ZrO2 mixed oxide to enhance the potential of CO2 adsorption and oxygen mobility. This enhancement facilitates its application as a support in catalysts for CO2 utilization such as CO2 reforming of methane (CRM). To achieve this perspective, γ-Al2O3 was modified with 10 wt.% of various MgO and ZrO2 contents (MgO:ZrO2= 10:0, 9:1,7:3, 5:5, 3:7, 1:9 and 0:10) using the impregnation method. All samples including unmodified γ-Al2O3 (Al) were characterized. Due to the increase in basicity and oxygen transfer around the surface, the improvement of the CO2 adsorption was observed on γ-Al2O3 modified with 9 wt.% MgO-1 wt.% ZrO2 (9Mg1ZrAl) and 10 wt.% MgO (10MgAl), respectively. An application of these two superior samples as a support of 10 wt.% Ni (10Ni) catalysts for CRM was investigated and compared with an unmodified γ-Al2O3. Characterization results suggest the formation of NiO-MgO solid solution at the surface due to the decrease in metal-support interaction and the increase in metal dispersion. The Ni catalysts with the surface-modified support show higher CO2 activity that raises carbon deposition resistance. The greatest coke prevention was observed on 10Ni/9Mg1ZrAl that lowers the coke deposition by 42% compared to 10Ni/Al. It indicates that the composition of this modification allowed very low ZrO2 portion to merge with MgO and MgO to form solid solution with NiO. This enables the 10Ni/9Mg1ZrAl catalyst to generate labile oxygens which can be conveyed to the Ni metal sites on the catalyst.

Hydroxyl and amino co-modified imidazole based ionic liquid functionalized TS-1 molecular sieve for efficient CO2 capture

Herein, an integrative solid adsorbent of [AHOPMIm]Cl with hydroxyl and amino groups functional sites modified TS-1 molecular sieve is designed and fabricated for efficient CO2 adsorption. The optimal [AHOPMIm]Cl/TS-1 exhibits 73% enhancement in CO2 adsorption capacity compared with the TS-1 molecular sieve, even outperforming other state of the art adsorbent systems. The greatly improved CO2 adsorption capacity is mainly attributed to the strong adsorption of amino groups on the ionic liquids surface, which can form low-temperature stable amino ester species. Moreover, it is preserved that the hydroxyl groups on the surface of ionic liquids can form stable hydrogen bonds with oxygen atoms in CO2, and coordinate with amino groups to capture CO2 from different directions based on in situ DRIFTS and DFT. The porous TS-1 molecular sieve provides a structural basis for the uniform dispersion, effective support, and enhanced CO2 adsorption capacity of ionic liquids. A new design concept for constructing ionic liquid-based composite adsorbent with dual functional sites using TS-1 molecular sieve as a carrier is provided, and the avenues for efficient CO2 adsorption are paved.

Enhanced Local CO Coverage on Cu Quantum Dots for Boosting Electrocatalytic CO2 Reduction to Ethylene

AbstractEthylene (C2H4) electrosynthesis from the electrocatalytic CO2 reduction process holds enormous potential applications in industrial production. However, the sluggish kinetics of C─C coupling often result in low yield and poor selectivity for C2H4 production. Herein, the performance of Cu catalysts of varying sizes is investigated, prepared via a cryo‐mediated liquid phase exfoliation technique, for the electrochemical CO2 reduction to C2H4. The activity and selectivity of C2H4 gradually increase as the size of the Cu catalysts decreases from tens of nanometers to a few nanometers. Impressively, the 5 nm Cu quantum dots (Cu‐5) achieve a maximum C2H4 Faradaic efficiency (FE) of 81.5% and a half‐cell cathodic energy efficiency (CEE) of 42.2% with a large partial current density of 1.1 A cm−2 at −0.93 V versus the reversible hydrogen electrode. Structural characterization and in situ spectroscopic analysis reveal that the Cu‐5 quantum dots, dominated by the (100) facet, provide an abundance of active sites that enhance CO2 adsorption and activation, promoting the formation of *CO intermediates. The accumulation of *CO intermediates on the Cu active sites facilitates the CO‐CHO coupling reaction, thus enhancing the C2H4 production rate.

Engineering Single Ni Sites on 3D Cage‐like Cucurbit[n]uril Ligands for Efficient and Selective CO2 Photocatalytic Reduction

Solar‐driven CO2 selective reduction with high conversion is a challenging task yet holds immense promise for both CO2 neutralization and green fuel production. Enhancing CO2 adsorption at the catalytic centre can trigger a highly efficient CO2 capture‐to‐conversion process. Herein, we introduce cucurbit[n]urils (CB[n]), a new family of molecular ligands, as a key component in the creation of a 3D cage‐like metal (nickel, Ni)‐complex molecular co‐catalyst (CB[7]‐Ni) for photocatalysis. It exhibits an unprecedented CO yield rate of 72.1 µmol· h‐1 with a high selectivity of 97.9% under visible light irradiation. To verify the origin of the carbon source in the products, a straightforward isotopic tracing method is designed based on tandem reactions. The catalytic process commences with photoelectron transfer from Ru(bpy)32+ to the Ni2+ site, resulting in the reduction of Ni2+ to Ni+. The locally enriched CO2 molecules in the cage ligand CB[7] undergo selective reduction by the Ni+ nearby to form CO product. This work exemplifies the inspiring potential of ligand structure engineering in advancing the development of efficient unanchored molecular co‐catalysts.

Engineering Single Ni Sites on 3D Cage-like Cucurbit[n]uril Ligands for Efficient and Selective CO2 Photocatalytic Reduction.

Solar-driven CO2 selective reduction with high conversion is a challenging task yet holds immense promise for both CO2 neutralization and green fuel production. Enhancing CO2 adsorption at the catalytic centre can trigger a highly efficient CO2 capture-to-conversion process. Herein, we introduce cucurbit[n]urils (CB[n]), a new family of molecular ligands, as a key component in the creation of a 3D cage-like metal (nickel, Ni)-complex molecular co-catalyst (CB[7]-Ni) for photocatalysis. It exhibits an unprecedented CO yield rate of 72.1 µmol· h-1 with a high selectivity of 97.9% under visible light irradiation. To verify the origin of the carbon source in the products, a straightforward isotopic tracing method is designed based on tandem reactions. The catalytic process commences with photoelectron transfer from Ru(bpy)32+ to the Ni2+ site, resulting in the reduction of Ni2+ to Ni+. The locally enriched CO2 molecules in the cage ligand CB[7] undergo selective reduction by the Ni+ nearby to form CO product. This work exemplifies the inspiring potential of ligand structure engineering in advancing the development of efficient unanchored molecular co-catalysts.

A molecular study of CO2 adsorption performance of functionalized Mg-MOF-74 at different water vapor concentrations and pressures

This study numerically evaluates the CO2 adsorption capability of functionalized Mg-MOF-74 at different water vapor concentrations and pressures. The −O-Li- and –NO2 display the most advantageous adsorption locations for CO2 and enhance the adsorption energy for H2O within the secondary building unit region. The enhancement of CO2 adsorption at 1 bar is achieved through the incorporation of Li-O and –NO2, whereas introducing –CH3 improves the selectivity of Mg-MOF-74 towards CO2/H2O. The absorption of CO2 at 10 bar is influenced by the available void space within the pores and altering the functional groups leads to a reduced porosity, thereby hindering the CO2 adsorption. However, –CH3 can effectively improve the CO2/H2O selectivity. The increased CO2 adsorption sites by the functionalization is more advantageous for enhancing CO2 adsorption capacity in gas/vapor mixtures at low pressures. Furthermore, enhancing absorbent hydrophobicity results in an enhanced selectivity for CO2/H2O, thereby facilitating CO2 adsorption at elevated pressures.

Promoting effect of CO2 on NiCr oxidation: Atomistic origins based on first principles.

The adsorption and dissociation of CO2 on both perfect and oxygen-deficient α-Cr2O3 (0001) surfaces, alongside the subsequent incorporation of the resulting C into the oxide lattice and its impact on oxide growth, are investigated using first-principles calculations. Our findings reveal that oxygen vacancies significantly enhance CO2 adsorption and promote its stepwise decomposition into C and O atoms. The resulting C can spontaneously dissolve into the oxide lattice through the oxygen vacancies. The presence of bulk dissolved C in the Cr2O3 lattice substantially enhances the formation, migration, and clustering of oxygen vacancies in the bulk. These results provide an atomic-level understanding of how CO2 accelerates the oxidation of chromia-forming alloys, offering microscopic insights for controlling oxide growth and mitigating oxidation-induced degradation of high-temperature alloys.

In-situ nitrogen-doped porous carbon derived from penicillin mycelial residue for CO2 adsorption and adsorption mechanism investigation

The in-situ nitrogen-doped porous carbon materials was synthesized using penicillin mycelial residue (PMR) as the sole endogenous nitrogen-rich precursor through a two-step process applied for CO2 adsorption. Precise control over the structural properties and CO2 adsorption performance of the porous carbon was achieved by varying the KOH dosage and activation temperature. The porous carbon prepared under mild activation conditions (600 ℃, KOH/BC = 1) exhibited high nitrogen content and abundant ultramicroporous structures (pore size ≤ 0.7 nm), and demonstrated outstanding adsorption performance. The CO2 adsorption capacities reached 6.55 mmol/g at 0 ℃ and 3.48 mmol/g at 25 ℃, showing promising CO2/N2 selectivity and robust cyclic adsorption stability. Quantitative structure–activity relationship analysis displayed a strong correlation between adsorption density, CO2/N2 selectivity, and nitrogen content. Density functional theory calculations further confirmed that nitrogen-doping, especially pyrrolic-N, serves as favorable structural sites for CO2 adsorption. Additionally, Grand Canonical Monte Carlo simulations verified that the ultramicroporous structures significantly enhances CO2 adsorption due to their strong affinity for CO2. This study provides an economic strategy for the preparation of in-situ nitrogen-doped porous carbon with enriched micropore using PMR, highlighting their promising performances in CO2 adsorption, synchronously extending the harmless treatment and resource utilization of PMR to demonstrate a sustainable approach for environmental remediation.

N-doped Porous Carbon Derived from the Pyrolysis of a Polydopamine-coated Hypercross-linked Polymer for Enhanced CO2 Adsorption.

Porous carbon materials can simultaneously capture and convert carbon dioxide, helping to reduce greenhouse gas emissions and using carbon dioxide as a feedstock for the production of valuable chemicals or fuel. In this work, a series of N-doped porous carbons (PDA@HCP(x:y)-T) was prepared; the CO2 adsorption capacity of the prepared PDA@HCP(x:y)-T was enhanced by coating polydopamine (PDA) on a hypercross-linked polymer (HCP) and then adjusting the mass ratio of PDA to HCP and the carbonization temperature. The results showed that the prepared PDA@HCP(1:1)-850 exhibited a high CO2 adsorption capacity due to abundant micropores (0.6762 cm3/g), a high specific surface area (1220.8 m²/g), and moderate surface nitrogen content (2.75%). Notably, PDA@HCP(1:1)-850 exhibited the highest CO2 uptake of 6.46 mmol/g at 0 °C and 101 kPa. Critically, these N-doped porous carbons can also be used as catalysts for the reaction of CO2 with epichlorohydrin to form chloropropylene carbonate, with chloropropylene carbonate yielding up to 64% and selectivity of the reaction reaching 94%. As a result, these N-doped porous carbons could serve as potential candidates for CO2 capture and conversion due to their high reactivity, excellent CO2 uptake, and good catalytic performance.

Comparison of micron- and nano-sized zeolite NaY composited with bamboo charcoal and their application in CO2 adsorption

This is the first report on synthesizing nano-sized zeolite NaY dispersed on acid-refluxed bamboo wood. The nano-sized NaY on the composite was produced by increasing the alkalinity in the seed gel. The as-synthesized composite was carbonized to convert the wood to charcoal and tested in CO2 adsorption. The CO2 adsorption capacity of nano- and micron-sized NaY composites was 2.30 and 1.25 mmol/g-composite. Moreover, nano-sized NaY composite shows higher adsorption capacity per gram of zeolite than bared nano-sized NaY. The dispersion of nano-sized zeolite on carbonaceous substrates could be an efficient strategy for enhancing CO2 adsorption.

A Highly Conjugated Nickel(II)-Acetylide Framework for Efficient Photocatalytic Carbon Dioxide Reduction.

The incorporation of transition-metal single atoms as molecular functional entities into the skeleton of graphdiyne (GDY) to construct novel two-dimensional (2D) metal-acetylide frameworks, known as metalated graphynes (MGYs), is a promising strategy for developing efficient catalysts, which can combine the tunable charge transfer of GDY frameworks, the catalytic activity of metal and the precise distribution of single metallic centers. Herein, four highly conjugated MGY photocatalysts based on NiII, PdII, PtII, and HgII were synthesized for the first time using the 'bottom-up' strategy through the use of M-C bonds (-C≡C-M-C≡C-). Remarkably, the NiII-based graphyne (TEPY-Ni-GY) exhibited the highest CO generation rate of 18.3 mmol g-1 h-1 and a selectivity of 98.8%. This superior performance is attributed to the synergistic effects of pyrenyl and -C≡C-Ni(PBu3)2-C≡C- moieties. The pyrenyl block functions as an intramolecular π-conjugation channel, facilitating kinetically favorable electron transfer, while the -C≡C-Ni(PBu3)2-C≡C- moiety serves as the catalytic site that enhances CO2 adsorption and activation, thereby suppressing competitive hydrogen evolution. This study provides a new perspective on MGY-based photocatalysts for developing highly active and low-cost catalysts for CO2 reduction.

Engineering hierarchical TiO2/ZnIn2S4 hybrid heterostructure with synergistic interfaces: A dual-functional S-scheme photocatalyst for efficient CO2 reduction and norfloxacin degradation

The development of multifunctional photocatalysts that can harness solar energy for both environmental remediation and energy generation is a considerable challenge in achieving sustainable development. This study introduces a dual-functional S-scheme hybrid catalyst comprising hierarchical 3D flower-like ZnIn2S4 (ZIS) microspheres embedded with TiO2 (TO) nanoparticles, synthesized via a facile in situ hydrothermal process. The unique structural and compositional synergy between ZIS and TO leverages their complementary photocatalytic properties, facilitating efficient solar energy utilization, increasing specific surface area, and enhancing CO2 adsorption capabilities. The S-scheme mechanism, confirmed by in situ-irradiated X-ray photoelectron spectroscopy and electron spin resonance spectroscopy, underlying this system promotes effective separation of photoexcited charge carriers while preserving the intrinsic strong reducibility of ZIS and high oxidizability of TO. These beneficial properties of the TO/ZIS hybrid provide a robust platform for CH4 production (75.6 μmol h−1 g−1) through selective (99.6 %) CO2 reduction over competing water reduction and achieve exceptional degradation and mineralization of the persistent antibiotic norfloxacin in water, addressing both energy and environmental challenges. Furthermore, the hybrid catalyst exhibits significant stability and recyclability, maintaining high catalytic performance across multiple cycles, thereby underscoring its practical viability. This work offers a promising blueprint for developing multifunctional photocatalysts capable of addressing critical global challenges, demonstrating the potential of hierarchical nanostructures and S-scheme charge transfer mechanisms.

Enhancing CO2 photoreduction efficiency with MXene-modified ZnO@Co3O4 double heterojunction

The photocatalytic reduction of CO2 into energy carriers holds significant industrial appeal, but achieving this process kinetically remains challenging due to the lack of well-designed catalysts. This study presents a novel 2D/3D nanostructured photocatalyst, developed by attaching a few-layer Ti3C2 MXene to polyethylenimine (PEI)-modified ZnO@CO3O4 nanocages, which are derived from a bimetallic zinc-cobalt ZIF. The resulting Mx-PEI-ZnO@Co3O4 catalyst achieved impressive yields of CO and CH4 at 594.37 and 42.67μmol g−1h−1, respectively, without the need for sacrificial agents and photosensitizers, and maintained remarkable stability across multiple cycles. These yields represent the highest performance for ZnO-based catalysts to date, with quantum efficiency at 380 nm reached up to 25.06 %. The unique S-scheme and Mott-Schottky junctions, along with enhanced CO2 adsorption and hydrogen-bond interactions facilitated by the conductive PEI within the Ti3C2/ZnO/Co3O4 double heterojunctions, effectively inhibit electron-hole recombination and significantly enhance CO2 photoreduction performance. This study underscores the combined benefits of double heterojunction engineering, PEI-functionalized CO2 uptake, and MXene co-catalyst integration within a single system, proposing a new approach for designing highly efficient photocatalysts for solar-driven CO2 reduction in energy-efficient fuel production.

Development of efficient CO2 adsorbents: Synthesis and performance evaluation of dopamine-modified halloysite nanotubes loaded with ZIF-8

Carbon capture, utilization, and storage (CCUS) is a crucial technology for achieving carbon reduction targets. The key to CCUS technology lies in developing and designing efficient and low-cost CO2 capture materials. Metal-organic frameworks (MOFs) have emerged as promising CO2 adsorbents in the field of carbon capture. However, high agglomeration of nanoparticles and high cost have severely hindered the application of MOF-based solid adsorbents. This study employs an in-situ growth method to prepare a novel “corncob-shaped” PHNT@ZIF-8 composite material. During the reaction process, surface modification of halloysite nanotubes (HNT) enhances the interaction between HNT and ZIF-8. The resulting PHNT@ZIF-8 exhibits an enhanced CO2 adsorption capacity of 1.48 mmol/g. Notably, the functionalized PHNT@ZIF-8 as CO2 adsorbents demonstrated significant adsorption properties: a high specific surface area of 409.74 m2/g, good selectivity in simulated flue gas composition of 15%/85% (CO2/N2) (39.1), excellent thermal stability, and superior regenerability. Moreover, PHNT@ZIF-8 adsorbs CO2 primarily through van der Waals forces, which involve low energy and are easily reversible. After eight adsorption–desorption cycles, CO2 capacity retention rate remains as high as 93% (1.37 mmol/g). This work enriches the repertoire of solid CO2 composite adsorbents, providing a novel pathway for enhancing CO2 adsorption performance.

Synergistic effect of carbon molecular sieve and alkali metal nitrate on promoting intermediate-temperature adsorption of CO2 over MgAl-layered double hydroxide

The development of intermediate-temperature adsorbents with high CO2 adsorption capacity is crucial for the tandem integration with CO2 hydrogenation catalyst, aimed at enhancing economy viability and minimizing energy consumption in Carbon capture, utilization and storage (CCUS). Although certain porous carbon materials (PCM) have been employed to enhance CO2 adsorption capability of layered double hydroxide (LDH), there remains an urgent necessity to identify more cost-effective and efficient PCM alternatives. Herein, alkali metal nitrates ((Li0.3Na0.18K0.52)NO3, hereafter referred to as LiNaK) modified layered double hydroxide (LDH)/carbon molecular sieve (CMS) composite (LiNaK-LDH/CMS) as promising adsorbents for CO2 capture was reported. The effects of CMS addition and nitrate loading, the calcination and adsorption temperature, as well as the cycling stability were investigated systematically. The results revealed that the CO2 capture capacity of the LiNaK-modified layered double oxide (LDO)/CMS composite (30 mol%LiNaK-LDO/CMS15%)-incorporating with 15 wt% CMS addition and 30 mol% nitrate loading-achieved a remarkable CO2 adsorption capacity of 1.32 mmol/g at 300 °C due to the synergetic interactions between CMS and nitrate; this represents nearly a sevenfold enhancement compared to initial LDO performance. Moreover, the 30 mol%LiNaK-LDO/CMS15% adsorbent also demonstrated commendable cyclic stability after ten adsorption cycles, retaining over 85 % of its initial adsorption capacity. Based on both obtained adsorption performance and characterization data from the adsorbents, a pre-adsorption enhancing CO2 intermediate-temperature adsorption mechanism over LiNaK-LDH/CMS composite through air calcination processes. This study significantly advances LDH-based adsorbent for future research into CO2 intermediate-temperature adsorption.

Post-crosslinking knitting strategy for triazine-functionalized ionic hypercrosslinked polymers: Enhanced CO2 adsorption and conversion

Pore engineering has gained significant recognition as a pivotal strategy to tailor the structure and functionality of porous materials. In this study, a post-crosslinking knitting strategy was employed to fabricate a series of triazine-functionalized ionic hypercrosslinked polymers (IHCPs) using low specific surface area ionic polymers as precursors and external crosslinkers α,α′-dichloro-p-xylene (DCX) and α,α′-dibromo-p-xylene (DBX) through the Friedel Crafts alkylation reaction. This post-crosslinking knitting methodology increases the specific surface area of the resulting IHCPs, leading to enhanced CO2 adsorption capabilities (reaching 1.92 mmol·g−1 at 1 bar and 273 K), enhanced a remarkable 5.6-fold increase in CO2 uptake compared to the original ionic polymers. Of particular interest, inclusion of –NH– groups in PTA-2-DBX exhibits a synergistic catalytic effect facilitated by hydrogen bonding interactions that enable efficient conversion of CO2 into various cyclic carbonates under solvent- and cocatalyst-free conditions with yields exceeding 99 %. Furthermore, PTA-2-DBX demonstrates excellent recyclability while maintaining its activity even after five consecutive cycles. This study offers an effective approach for modulating pores in ionic polymers while highlighting the promising applications of triazine-functionalized IHCPs as dual-functional materials for both CO2 capture and conversion.

Development of Ce-doped NH2-UiO-66(Zr) photocatalysts for efficient CO2 reduction in an aqueous system

A series of bimetallic NH2-UiO-66(Zr/Ce) catalysts with varying Zr/Ce molar ratios were synthesized using a straightforward solvothermal method. Among the tested samples, NH2-UiO-66(Zr/Ce1:1) demonstrated superior performance, attributed to its optimized electronic structure, enhanced CO2 adsorption capacity, and efficient separation of photogenerated electron-hole pairs, outperforming the NH2-UiO-66(Zr) variant. The NH2-UiO-66(Zr/Ce1:1) exhibited a bandgap of 2.67 eV, CO2 adsorption capacity of 65.85 cm3/g, and a photocurrent density of 0.43 μA·cm−2. This catalyst achieved achieving a CO production rate of 30.04 μmol·g−1·h−1, representing a 1.66-fold improvement over NH2-UiO-66(Zr), with CO selectivity increasing from 95.2 % to 97.2 %. The results underscore the efficacy of Zr/Ce bimetallic NH2-UiO-66 for CO2 reduction, highlighting the potential of structural modifications in NH2-UiO-66 to enhance photocatalytic performance. This study provides valuable insights into the design and development of advanced catalysts for efficient and sustainable CO2 reduction.