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The energy sector has demonstrated significant enthusiasm for investigating post‐combustion CO2 capture, storage, and separation. However, the practical application of current porous adsorbents is impeded by challenges related to cost competitiveness, stability, and scalability. Intregation of heteroatoms in the porous organic polymers (POPs) dispense it more susceptible for CO2 adsorption to attenuate green house gases. In this regard, two hydroxy rich hypercrosslinked POPs, namely Ph/Tt‐POP have been developed by one‐pot condensation polymerization using a facile synthetic strategy. The high surface areas of both the Ph/Tt‐POP (1057 and 893 m2g−1, respectively), and the heteroatom functionality in the POP framework instigated us to explore our material for CO2 adsorption study. The CO2 uptake capacities in Ph/Tt‐POP are found to be 2.45 and 2.2 mmol g−1, at 273 K respectively. Further, in‐situ static 13C NMR experiment shows that CO2 molecules in Tt‐POP appear to be less mobile than those in Ph‐POP which probably due to the presence of triazine functional groups along with high abundant −OH groups in the Tt‐POP framework. An in‐depth study of the CO2 adsorption mechanism by density functional theory (DFT) calculations also shows that CO2 adsorption at the cages formed by two benzyl rings represents the most stable interaction and CO2 molecule is more favorably adsorbed on the Ph‐POP with the more negative interaction energies values compared to that of Tt‐POP. Further, Non‐covalent interaction (NCI) plot reveals that CO2 molecules adsorb more on the Ph‐POP than Tt‐POP, which can be explain by hydrogen bond formation in case of Tt‐POP repeating units turning aside CO2 molecule to interact with the Ph component. Overall, our present study reflects the comprising effects of surface area of the solid adsorbents as well as their functionality can be beneficial for developing efficient hypercrosslinked porous polymers as solid CO2 adsorbent. [ABSTRACT FROM AUTHOR]

Herein, we have specifically designed two metalated porous organic polymers (Zn‐POP and Co‐POP) for syngas (CO+H2) production from gaseous CO2. The variable H2/CO ratio of syngas with the highest efficiency was produced in water medium (without an organic hole scavenger and photosensitizer) by utilizing the basic principle of Lewis acid/base chemistry. Also, we observed the formation of entirely different major products during photocatalytic CO2 reduction and water splitting with the help of the two catalysts, where CO (145.65 μmol g−1 h−1) and H2 (434.7 μmol g−1 h−1) production were preferentially obtained over Co‐POP & Zn‐POP, respectively. The higher electron density/better Lewis basic nature of Co‐POP was investigated further using XPS, XANES, and NH3‐TPD studies, which considerably improve CO2 activation capacity. Moreover, the structure–activity relationship was confirmed via in situ DRIFTS and DFT studies, which demonstrated the formation of COOH* intermediate along with the thermodynamic feasibility of CO2 reduction over Co‐POP while water splitting occurred preferentially over Zn‐POP. [ABSTRACT FROM AUTHOR]

Chemical warfare agents (CWAs) have been classified as fatal weapons of mass destruction because of their toxicity and deadly consequences. Among other CWAs, sulfur mustards (HDs) were employed during the Iraq–Iran war (1984–1988), causing significant fatal effects for 100 000 military and civilian Iranians, and around 45000 people are still suffering from long-term health repercussions. Hence, the detection and detoxification of these acutely dangerous chemicals are critical for protecting ourselves and have thus sparked much scientific interest around the globe. In this regard, studies show that various photoresponsive porous organic materials like activated metal–organic-frameworks (MOFs), porous organic polymers (POPs), covalent organic frameworks (COFs), and TiO2-derived materials are highly effective for the photochemical detoxification of HDs. Given this context, we have traversed through the history of developing various photoresponsive porous materials and their efficacy in detoxifying CWAs, notably HDs. Moreover, we highlighted the numerous research methodologies reported to detect and modulate the excitonic effects in photoporous materials, which can tune the in situ-generated reactive oxygen species (ROS) responsible for HD detoxification. Lastly, we have listed the hurdles in creating photoactive porous materials and functionalizing them for large-scale HD detoxification. Although most of the described porous photocatalysts demonstrated good lab-scale performance, relatively few are accessible for large-scale industrial use. We have also addressed the future needs and potential for employing photoporous materials for efficient detoxification of HDs on an industrial scale to alleviate the issue of CWA/HD stockpiling and their potential use as a weapon of mass destruction. [ABSTRACT FROM AUTHOR]

The electrochemical fixation of carbon dioxide (CO2) into organic halides is one of the most prominent strategies for mitigating atmospheric CO2 emission, along with the difficulties associated with the toxic and carcinogenic halogenated compounds. Cu-based nanomaterials have been explored for numerous applications in nanotechnology, including electrocatalysis, organic catalytic transformations, and photocatalysis. In this work, we have designed and developed a Cu-embedded carbazole-derived porous organic polymer (Cu@Cz-POP) nanohybrid by utilizing the Friedel–Crafts alkylation approach and employing 1,4-dimethoxybenzene as the cross-linking agent comprising unique characteristic features of the extended π-conjugated system along with an active metal center with tunable electrochemical properties. The Brunauer–Emmett–Teller surface area of the conjugated Cz-POP is found to be 1060 m2 g–1. The X-ray photoelectron spectroscopy (XPS) study demonstrates the formation of CuO nanoparticles in the polymeric framework. X-ray absorption fine structure analysis (EXAFS) also reveals the existence of CuO with a smaller fraction of Cu in the polymeric framework, which is corroborated with the XPS analysis. The Cu@Cz-POP nanohybrid is fabricated by drop-casting over a Ni foam, showing promising electrocatalytic activity toward electrocarboxylation of benzyl bromide in 0.1 M TBA·BF4/CH3CN with saturated CO2 medium with a current density of 120 mA cm–2 delivering 65% yield of phenylacetic acid (PAA) as the primary product along with traces of benzyl 2-phenylacetate (BPA) and 1,2-diphenylethane (DPE), and the turnover frequency is found to be 8.556 × 10–7 s–1. Density functional theory calculations demonstrate that CuO is adsorbed more favorably at the N1 nitrogen atom of Cz-POP. An electron transfer from the N1 atom and the aromatic rings of Cz-POP to the CuO center is observed and confirmed by the overlap of alpha orbitals. [ABSTRACT FROM AUTHOR]

Herein, we have designed and synthesized two heteroatom (N, O) rich covalent organic frameworks (COF), PD‐COF and TF‐COF, respectively, to demonstrate their relative effect on CO2 adsorption capacity and also CO2/N2 selectivity. Compared to the non‐fluorinated PD‐COF (BET surface area 805 m2 g−1, total pore volume 0.3647 ccg−1), a decrease in BET surface area and also pore volume have been observed for fluorinated TF‐COF due to the incorporation of fluorine to the porous framework (BET surface area 451 m2 g−1, total pore volume 0.2978 ccg−1). This fact leads to an enormous decrease in the CO2 adsorption capacity and CO2/N2 selectivity of TF‐COF, though it shows stronger affinity towards CO2 with a Qst of 37.76 KJ/mol. The more CO2 adsorption capacity by PD‐COF can be attributed to the large specific surface area with considerable amount of micropore volume compared to the TF‐COF. Further, PD‐COF exhibited CO2/N2 selectivity of 16.8, higher than that of TF‐COF (CO2/N2 selectivity 13.4). [ABSTRACT FROM AUTHOR]

Using a catalyst-free one-pot polycondensation approach, a new donor–acceptor (D–A) based porous polyimide (PeTt–POP) photocatalyst was developed. PeTt–POP produced CH4 (125.63 ppm g−1 in 6 h) from CO2 under visible light irradiation in the gas–solid mode without the use of co-catalysts or sacrificial agents. The progress of the reaction and the corresponding intermediate species involved in the CO2 reduction were identified by operando DRIFTS experiments, from which a plausible reaction mechanism was proposed. [ABSTRACT FROM AUTHOR]

Post-combustion CO2 capture, storage, and separation have garnered colossal research interest in the energy industry, although realistic implementation of the available porous adsorbents is restricted owing to their cost competitiveness, stability, and scalability issues. The integration of heteroatom functionalities (N, O, or S) at the molecular level into the organic skeleton of porous framework materials endowed them with superior CO2 adsorbents to mitigate greenhouse gases. In this work, we have successfully introduced triazine–thiophene (Tt) groups to the nanoporous organic polymer (POP) skeleton by Friedel–Craft alkylation of Tt (as a monomer) with a series of cross-linking agents including formaldehyde dimethyl acetal, 1,4-bis-(bromomethyl)-benzene (BMB), and 4,4′-bis-(bromomethyl)-biphenyl, which contained methylene, bis-methylene benzene, and bis-methylene biphenyl moieties in each linker unit, respectively. The precise skeleton engineering with the variation of organic cross-linking agents at the molecular level leads to the development of Tt-POP-1, Tt-POP-2, and Tt-POP-3, having nanorod-, nanocoral-, and nanocloud-like morphologies, respectively. In particular, at 273 K, Tt-POP- 1, Tt-POP- 2, and Tt-POP-3 exhibited CO2 uptake capacities of about 33.04, 40.06, and 34.12 cm3/g, respectively, up to 1 bar pressure. Interestingly, Tt-POP-2 bearing a BMB linker exhibited enhanced CO2 uptake capacity both at 298 and 273 K in comparison with the other Tt-POP-1 and Tt-POP-3, respectively. An in-depth study of the CO2 adsorption mechanism by density functional theory calculations showed that the benzyl rings of linker units in Tt-POP-2 and Tt-POP-3 play a pivotal role in CO2 uptake. The more polarized interaction of CO2 with the thiophenyl and benzyl rings compared to the N and S atoms in Tt-POP-2 results in enhanced CO2 uptake capacity with respect to the others. [ABSTRACT FROM AUTHOR]

The energy sector has demonstrated significant enthusiasm for investigating post-combustion CO 2 capture, storage, and separation. However, the practical application of current porous adsorbents is impeded by challenges related to cost competitiveness, stability, and scalability. Intregation of heteroatoms in the porous organic polymers (POPs) dispense it more susceptible for CO 2 adsorption to attenuate green house gases. In this regard, two hydroxy rich hypercrosslinked POPs, namely Ph/Tt-POP have been developed by one-pot condensation polymerization using a facile synthetic strategy. The high surface areas of both the Ph/Tt-POP (1057 and 893 m 2 g -1 , respectively), and the heteroatom functionality in the POP framework instigated us to explore our material for CO 2 adsorption study. The CO 2 uptake capacities in Ph/Tt-POP are found to be 2.45 and 2.2 mmol g -1 , at 273 K respectively. Further, in-situ static 13 C NMR experiment shows that CO 2 molecules in Tt-POP appear to be less mobile than those in Ph-POP which probably due to the presence of triazine functional groups along with high abundant -OH groups in the Tt-POP framework. An in-depth study of the CO 2 adsorption mechanism by density functional theory (DFT) calculations also shows that CO 2 adsorption at the cages formed by two benzyl rings represents the most stable interaction and CO 2 molecule is more favorably adsorbed on the Ph-POP with the more negative interaction energies values compared to that of Tt-POP. Further, Non-covalent interaction (NCI) plot reveals that CO 2 molecules adsorb more on the Ph-POP than Tt-POP, which can be explain by hydrogen bond formation in case of Tt-POP repeating units turning aside CO 2 molecule to interact with the Ph component. Overall, our present study reflects the comprising effects of surface area of the solid adsorbents as well as their functionality can be beneficial for developing efficient hypercrosslinked porous polymers as solid CO 2 adsorbent., (© 2024 Wiley-VCH GmbH.)

Herein, a facile strategy is illustrated to develop pyrolysis-free out-of-plane coordinated single atomic sites-based M-POP via a one-pot Friedel Craft acylation route followed by a post-synthetic metalation. The optimized geometry of the Co@BiPy-POP clearly reveals the presence of out-of-plane Co-single atomic sites in the porous backbone. This novel photopolymer Co@BiPy-POP shows extensive π-conjugations followed by impressive light harvesting ability and is utilized for photochemical CO 2 fixation to value-added chemicals. A remarkable conversion of styrene epoxide (STE) to styrene carbonate (STC) (≈98%) is obtained under optimized photocatalytic conditions in the existence of promoter tert-butyl ammonium bromide (TBAB). Synchrotron-based X-ray adsorption spectroscopy (XAS) analysis reveals the single atom coordination sites along with the metal (Co) oxidation number of +2.16 in the porous network. Moreover, in situ diffuse reflectance spectroscopy (DRIFTS) and electron paramagnetic resonance (EPR) investigations provide valuable information on the evolution of key reaction intermediates. Comprehensivecomputational analysis also helps to understand the overall mechanistic pathway along with the interaction between the photocatalyst and reactants. Overall, this study presents a new concept of fabricating porous photopolymers based on a pyrolysis-free out-of-plane-coordination strategy and further explores the role of single atomic sites in carrying out feasible CO 2 fixation reactions., (© 2023 Wiley-VCH GmbH.)

Herein, we have specifically designed two metalated porous organic polymers (Zn-POP and Co-POP) for syngas (CO+H 2 ) production from gaseous CO 2 . The variable H 2 /CO ratio of syngas with the highest efficiency was produced in water medium (without an organic hole scavenger and photosensitizer) by utilizing the basic principle of Lewis acid/base chemistry. Also, we observed the formation of entirely different major products during photocatalytic CO 2 reduction and water splitting with the help of the two catalysts, where CO (145.65 μmol g -1  h -1 ) and H 2 (434.7 μmol g -1  h -1 ) production were preferentially obtained over Co-POP & Zn-POP, respectively. The higher electron density/better Lewis basic nature of Co-POP was investigated further using XPS, XANES, and NH 3 -TPD studies, which considerably improve CO 2 activation capacity. Moreover, the structure-activity relationship was confirmed via in situ DRIFTS and DFT studies, which demonstrated the formation of COOH* intermediate along with the thermodynamic feasibility of CO 2 reduction over Co-POP while water splitting occurred preferentially over Zn-POP., (© 2023 Wiley-VCH GmbH.)

The development of an efficient photocatalyst for C2 product formation from CO 2 is of urgent importance toward the deployment of solar-fuel production. Here, we report a template-free, cost-effective synthetic strategy to develop a carbazole-derived porous organic polymer (POP)-based composite catalyst. The composite catalyst is comprised of In 2.77 S 4 and porous organic polymer (POP) and is held together by induced-polarity-driven electrostatic interaction. Utilizing the synergy of the catalytically active In centers and light-harvesting POPs, the catalyst showed 98.9% selectivity toward the generation of C 2 H 4 , with a formation rate of 67.65 μmol g -1 h -1 . Two different oxidation states of the In 2.77 S 4 spinel were exploited for the C-C coupling process, and this was investigated by X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and density functional theory (DFT) calculations. The role of POP was elucidated via several photophysical and photoelectrochemical studies. The electron transfer was mapped by several correlated approaches, which assisted in establishing the Z-scheme mechanism. Furthermore, the mechanism of C 2 H 4 formation was extensively investigated using density functional theory (DFT) calculations from multiple possible pathways.

Herein, we have designed and synthesized two heteroatom (N, O) rich covalent organic frameworks (COF), PD-COF and TF-COF, respectively, to demonstrate their relative effect on CO 2 adsorption capacity and also CO 2 /N 2 selectivity. Compared to the non-fluorinated PD-COF (BET surface area 805 m 2  g -1 , total pore volume 0.3647 ccg -1 ), a decrease in BET surface area and also pore volume have been observed for fluorinated TF-COF due to the incorporation of fluorine to the porous framework (BET surface area 451 m 2  g -1 , total pore volume 0.2978 ccg -1 ). This fact leads to an enormous decrease in the CO 2 adsorption capacity and CO 2 /N 2 selectivity of TF-COF, though it shows stronger affinity towards CO 2 with a Qst of 37.76 KJ/mol. The more CO 2 adsorption capacity by PD-COF can be attributed to the large specific surface area with considerable amount of micropore volume compared to the TF-COF. Further, PD-COF exhibited CO 2 /N 2 selectivity of 16.8, higher than that of TF-COF (CO 2 /N 2 selectivity 13.4)., (© 2022 Wiley-VCH GmbH.)

Using a catalyst-free one-pot polycondensation approach, a new donor-acceptor (D-A) based porous polyimide (PeTt-POP) photocatalyst was developed. PeTt-POP produced CH 4 (125.63 ppm g -1 in 6 h) from CO 2 under visible light irradiation in the gas-solid mode without the use of co-catalysts or sacrificial agents. The progress of the reaction and the corresponding intermediate species involved in the CO 2 reduction were identified by operando DRIFTS experiments, from which a plausible reaction mechanism was proposed.

Anthropogenic carbon dioxide (CO 2 ) emission is soaring day by day due to fossil fuel combustion to fulfill the daily energy requirements of our society. The CO 2 concentration should be stabilized to evade the deadly consequences of it, as climate change is one of the major consequences of greenhouse gas emission. Chemical fixation of CO 2 to other value-added chemicals requires high energy due to its stability at the highest oxidation state, creating a tremendous challenge to the scientific community to fix CO 2 and prevent global warming caused by it. In this work, we have introduced a novel monomer-assembly-directed strategy to design va isible-light-responsive conjugated Zn-metalated porous organic polymer ( Zn@MA-POP ) with a dynamic covalent acyl hydrazone linkage, via a one-pot condensation between the self-assembled monomer 1,3,5-benzenetricarbohydrazide ( TPH ) and a Zn complex ( Zn@COM ). We have successfully explored as-synthesized Zn@MA-POP as a potential photocatalyst in visible-light-driven CO 2 photofixation with styrene epoxide ( SE ) to styrene carbonate ( SC ). Nearly 90% desired product ( SC ) selectivity has been achieved with our Zn@MA-POP , which is significantly better than that for the conventional Zn@TiO 2 (∼29%) and Zn@gC 3 N 4 (∼26%) photocatalytic systems. The excellent light-harvesting nature with longer lifetime minimizes the radiative recombination rate of photoexcited electrons as a result of extended π-conjugation in Zn@MA-POP and increased CO 2 uptake, eventually boosting the photocatalytic activity. Local structural results from a first-shell EXAFS analysis reveals the existence of a Zn(N 2 O 4 ) core structure in Zn@MA-POP , which plays a pivotal role in activating the epoxide ring as well as capturing the CO 2 molecules. An in-depth study of the POP-CO 2 interaction via a density functional theory (DFT) analysis reveals two feasible interactions, Zn@MA-POP-CO 2 -A and Zn@MA-POP-CO 2 -B , of which the latter has a lower relative energy of 0.90 kcal/mol in comparison to the former. A density of states (DOS) calculation demonstrates the lowering of the LUMO energy (EL) of Zn@MA-POP by 0.35 and 0.42 eV, respectively, for the two feasible interactions, in comparison to Zn@COM . Moreover, the potential energy profile also unveils the spontaneous and exergonic photoconversion pathways for the SE to SC conversion. Our contribution is expected to spur further interest in the precise design of visible-light-active conjugated porous organic polymers for CO 2 photofixation to value-added chemicals.