Ethanol Selectivity Research Articles

A Noncovalent π‐Stacked Dual‐Pore Molecular Crystal for Ethanol/Water and Benzene/Methanol Azeotrope Separation

Separation of ethanol/water or benzene/methanol azeotrope mixtures presents significant challenges, not only due to the limitations of conventional distillation techniques but also because of the constraints in developing and utilizing of new generation adsorbents. Porous organic molecular frameworks constructed via noncovalent π‐interactions are emerging as novel adsorbents with vast potential in gas adsorption and molecular separation. Herein, we report a permanent two‐dimensional porous structure, namely TDTBA‐1, which consists of two different kinds of pores through π‐stacking of a single organic molecule with highly Td symmetry. Activated TDTBA‐1 exhibits excellent hydrophobicity, thermal stability, recoverability and high selectivity for ethanol over water, and benzene over methanol. Therefore, activated TDTBA‐1 can be used as an efficient stationary phase for the separation of ethanol/water and benzene/methanol azeotropes by high‐resolution gas chromatography.

A Noncovalent π-Stacked Dual-Pore Molecular Crystal for Ethanol/Water and Benzene/Methanol Azeotrope Separation.

Separation of ethanol/water or benzene/methanol azeotrope mixtures presents significant challenges, not only due to the limitations of conventional distillation techniques but also because of the constraints in developing and utilizing of new generation adsorbents. Porous organic molecular frameworks constructed via noncovalent π-interactions are emerging as novel adsorbents with vast potential in gas adsorption and molecular separation. Herein, we report a permanent two-dimensional porous structure, namely TDTBA-1, which consists of two different kinds of pores through π-stacking of a single organic molecule with highlyTdsymmetry. Activated TDTBA-1 exhibits excellent hydrophobicity, thermal stability, recoverability and high selectivity for ethanol over water, and benzene over methanol. Therefore, activated TDTBA-1 can be used as an efficient stationary phase for the separation of ethanol/water and benzene/methanol azeotropes by high-resolution gas chromatography.

Lithium iodide promoted CO2 hydrogenation towards ethanol via biphasic lewis-acid-base pairs synergistic catalysis

Ethanol synthesis via CO2 hydrogenation is of great importance in view of its high-value utilization. Herein, combining with heterogeneous and homogenous catalysis, we have developed an efficient biphasic Lewis-acid-base pairs synergistic catalysis strategy from CO2 hydrogenation. Apart from conventional heterogeneous ethanol synthesis route, it was surprisingly found that LiI homogenous promoter significantly enhanced CO2 conversion, ethanol selectivity, and productivity. LiI promoted CO2 dissolution in pure water and accelerated reaction intermediates consumption, favoring CO2 conversion. In detail, it can weaken C-O bond of CH3OH intermediate through Li+-I- Lewis-acid-base catalysis. The formed CH3I* with lower bond energy for C-I was more facile to dissociate into CH3*, favoring its subsequent coupling with CO* to form ethanol. In combination of Rh1/CeTiOx catalyst, LiI promoter, and methanol as solvent, a record-breaking ethanol yield was achieved (223.1 mmol·g−1·h−1). The obtained ethanol yield was about 18.7 times of that reported the best result in literatures. Especially, the established catalyst system could also be applied for synthesis of higher-carbon-number alcohols by the CO2 hydrogenation with other alcohols solvent (CnH2n+1OH, n = 2,3…).

Switching CO2 Electroreduction Pathways between Ethylene and Ethanol via Tuning Microenvironment of the Coating on Copper Nanofibers

AbstractEngineering the microenvironment of electrode surface is one of the effective means to tune the reaction pathways in CO2RR. In this work, we prepared copper nanofibers with conductive polypyrrole coating by polymerization of pyrrole using polyvinyl pyrrolidone (PVP) as template. As a result, the obtained copper nanofibers Cu/Cu2+1O/SHNC, exhibited a superhydrophobic surface, which demonstrated very high selectivity for ethanol with a Faraday efficiency (FE) of 66.5 % at −1.1 V vs reversible hydrogen electrode (RHE) in flow cell. However, the catalyst Cu/Cu2+1O/NC, which was prepared under the same conditions but without PVP, possessed a hydrophobic surface and exhibited high selectivity towards ethylene at the given potentials. The mechanism for switch of reaction pathways from ethylene to ethanol in CO2RR was studied. Incorporating pyrrolidone groups into the polymer coating results in the formation of a superhydrophobic surface. This surface weakens the hydrogen bonding interaction between interfacial water molecules and facilitates the transfer of CO2, thereby enhancing the local CO2/H2O ratio. The high coverage of *CO promotes the coupling of *CO and *CHO to form C2 intermediates, and reduces the reaction energy for the formation of *CHCHOH (ethanol path) at the interface. This ensures that the reaction pathway is directed towards ethanol.

Nickel-Doped Facet-Selective Copper Nanowires for Activating CO-to-Ethanol Electrosynthesis.

Ethanol isa promising energy vector for closing the anthropogenic carbon cycle through reversible electrochemical redox. Currently, ethanol electrosynthesissuffers from low product selectivity due to the competitive advantage of ethylene in CO2/CO electroreduction. Here, a facet-selective metal-doping strategy is reported, tuning the reaction kinetics of CO reduction paths and thus enhancing the ethanol selectivity. The theoretical calculations reveal that nickel (Ni)doped Cu(100) surface facilitates water dissociation to form adsorbed hydrogen, which promotesselective electrochemical hydrogenation of a key C2 intermediate (*CHCOH) toward ethanol path over ethylene path. Experimentally, a solution-phase synthesis of a Ni-doped {100}-dominated Copper nanowires (Cu NWs) catalyst is reported, enabling an ethanol Faradaic efficiency of 56% and a selectivity ratio of ethanol to ethylene of 2.7, which are ≈4 and 15 times larger than those of undoped Cu NWs, respectively. The operando spectroscopic characterizationsconfirm that Ni-doping in Cu NWs can alter the interfacial water activity and thus regulate the C2 product selectivity. With further electrode engineering, a membrane electrode assembly electrolyzer using Ni-doped Cu NWs catalysts demonstrates an ethanol Faradaic efficiency over 50% at 300mA cm-2 with a full cell voltage of ≈2.7V and operates stably for over 300 h.

Asymmetrically Coordinated Cu Dual-Atom-Sites Enables Selective CO2 Electroreduction to Ethanol.

Electrochemical reduction of CO2 (CO2RR) to value-added liquid fuels is a highly attractive solution for carbon-neutral recycling, especially for C2+ products. However, the selectivity control to preferable products is a great challenge due to the complex multi-electron proton transfer process. In this work, a series of Cu atomic dispersed catalysts are synthesized by regulating the coordination structures to optimize the CO2RR selectivity. Cu2-SNC catalyst with a uniquely asymmetrical coordinated CuN2-CuNS site shows high ethanol selective with the FE of 62.6% at -0.8V versus RHE and 60.2% at 0.9V versus RHE in H-Cell and Flow-Cell test, respectively. Besides, the nest-like structure of Cu2-SNC is beneficial to the mass transfer process and the selection of catalytic products. In situ experiments and theory calculations reveal the reaction mechanisms of such high selectivity of ethanol. The S atoms weaken the bonding ability of the adjacent Cu to the carbon atom, which accelerates the selection from *CHCOH to generate *CHCHOH, resulting in the high selectivity of ethanol. This work indicates a promising strategy in the rational design of asymmetrically coordinated single, dual, or tri-atom catalysts and provides a candidate material for CO2RR to produce ethanol.

Highly selective ethanol vapour sensing materials for a new generation of gas sensors based on molecularly imprinted polymers

A simple gas sensor consisting of a molecularly imprinted polymer-carbon nanotube composite cast onto a screen-printed electrode has been developed with extremely high selectivity for ethanol vapour over methanol vapour. Ethanol gas sensors typically display selectivity for ethanol over methanol in the range 2–4 times, while the mean ratio of ethanol to methanol response observed with the described device was 672. This selectivity was achieved under ambient conditions. Additionally, the molecularly imprinted polymer was produced using reagents previously applied in the development of a device selective for methanol, with only the template being changed. This demonstrates the versatility of molecular imprinting and provides a foundation for their greater integration into future gas sensors.

Multivalent Cu sites synergistically adjust carbonaceous intermediates adsorption for electrocatalytic ethanol production

Copper (Cu)-based catalysts show promise for electrocatalytic CO2 reduction (CO2RR) to multi-carbon alcohols, but thermodynamic constraints lead to competitive hydrocarbon (e.g., ethylene) production. Achieving selective ethanol production with high Faradaic efficiency (FE) and current density is still challenging. Here we show a multivalent Cu-based catalyst, Cu-2,3,7,8-tetraaminophenazine-1,4,6,9-tetraone (Cu-TAPT) with Cu2+ and Cu+ atomic ratio of about 1:2 for CO2RR. Cu-TAPT exhibits an ethanol FE of 54.3 ± 3% at an industrial-scale current density of 429 mA cm−2, with the ethanol-to-ethylene ratio reaching 3.14:1. Experimental and theoretical calculations collectively unveil that the catalyst is stable during CO2RR, resulting from suitable coordination of the Cu2+ and Cu+ with the functional groups in TAPT. Additionally, mechanism studies show that the increased ethanol selectivity originates from synergy of multivalent Cu sites, which can promote asymmetric C–C coupling and adjust the adsorption strength of different carbonaceous intermediates, favoring hydroxy-containing C2 intermediate (*HCCHOH) formation and formation of ethanol.

Enhanced ethanol response, selectivity, and stability of ZIF-67-derived ZnO/Co3O4 bimetallic oxide composites

This study aims to develop an efficient, stable, highly humidity-resistant, and selective ethanol sensing material. In this study, ZIF-67-derived ZnO/Co3O4 bimetallic oxide composite materials were synthesized via a co-precipitation method followed by a one-pot hydrothermal reaction. Different mass ratios (10 %, 30 %, 50 %) of ZIF-67-Derived ZnO/Co3O4 composite materials were obtained by varying the mass of Co3O4. The ethanol sensing performance of these composite materials were investigated. Results demonstrated that the ZnO/Co3O4-ZIF30 % sensor exhibited a response value of 42.3 for 50 ppm ethanol at 240 °C, with response and recovery times of 50 s and 200 s, respectively. Furthermore, the ZnO/Co3O4-ZIF30 % sensor showed almost no change in response value as humidity increased from 30 % RH to 80 % RH, indicating remarkably high humidity resistance. Additionally, ZnO/Co3O4-ZIF30 % exhibited high selectivity for ethanol. Consequently, the ZnO/Co3O4-ZIF30 % material demonstrated superior ethanol sensing performance. Finally, the multiple gas sensing mechanisms of ZIF-67-derived ZnO/Co3O4 composites were carefully investigated. In conclusion, the ZnO/Co3O4-ZIF30 % material demonstrated outstanding ethanol sensing performance, indicating its significant potential for practical applications.

Synergistic promotion strategy of “dual-site” and “dual-path” to enhance the C–C coupling between CO2 and HCHO driven by photoelectrocatalysis

Photoelectrocatalytic coupling CO2 and volatile organic compounds (VOCs) is a promising green strategy for the synergistic conversion of the two carbon-containing resources to C2 products. The catalytic efficiency is always at the mercy of chemical inertness of CO2 and the competitive hydrogen evolution of H2O. Herein, a modified g-C3N4/ZnAl-LDH Z-scheme heterojunction catalyst with dual reaction site was rationally designed and precisely constructed. The Faraday efficiency of ethanol reached 68.67% with a corresponding formation rate of 227.3 μmol g−1 h−1. As revealed by in-situ characterizations and density functional theory calculations, CO2 and HCHO were absorbed at Zn site and N site, respectively. Then, *CO generated from CO2 and HCHO was converted to *CH3O and *CHO on the dual-active-site heterojunction. The detailed reaction mechanism experiments indicated that C–C coupling only occurred between *CO and *CH3O in electrocatalysis process. Apart from the “*CO + *CH3O” path, another “*CO + *CHO” coupling path was also detected in photoelectrocatalytic process. The selectivity of ethanol was significantly enhanced due to the synthesis of dual-site catalyst and the dual-path coupling path between CO2 and HCHO simultaneously driven by light and electricity.

Metal–Organic Framework Supported Low‐Nuclearity Cluster Catalysts for Highly Selective Carbon Dioxide Electroreduction to Ethanol

AbstractIt is still a great challenge to achieve high selectivity of ethanol in CO2 electroreduction reactions (CO2RR) because of the similar reduction potentials and lower energy barrier of possible other C2+ products. Here, we report a MOF‐based supported low‐nuclearity cluster catalysts (LNCCs), synthesized by electrochemical reduction of three‐dimensional (3D) microporous Cu‐based MOF, that achieves a single‐product Faradaic efficiency (FE) of 82.5 % at −1.0 V (versus the reversible hydrogen electrode) corresponding to the effective current density is 8.66 mA cm−2. By investigating the relationship between the species of reduction products and the types of catalytic sites, it is confirmed that the multi‐site synergism of Cu LNCCs can increase the C−C coupling effect, and thus achieve high FE of CO2–to–ethanol. In addition, density functional theory (DFT) calculation and operando attenuated total reflectance surface‐enhanced infrared absorption spectroscopy further confirmed the reaction path and mechanism of CO2–to–EtOH.

Metal-Organic Framework Supported Low-Nuclearity Cluster Catalysts for Highly Selective Carbon Dioxide Electroreduction to Ethanol.

It is still a great challenge to achieve high selectivity of ethanol in CO2 electroreduction reactions (CO2RR) because of the similar reduction potentials and lower energy barrier of possible other C2+ products. Here, we report a MOF-based supported low-nuclearity cluster catalysts (LNCCs), synthesized by electrochemical reduction of three-dimensional (3D) microporous Cu-based MOF, that achieves a single-product Faradaic efficiency (FE) of 82.5 % at -1.0 V (versus the reversible hydrogen electrode) corresponding to the effective current density is 8.66 mA cm-2. By investigating the relationship between the species of reduction products and the types of catalytic sites, it is confirmed that the multi-site synergism of Cu LNCCs can increase the C-C coupling effect, and thus achieve high FE of CO2-to-ethanol. In addition, density functional theory (DFT) calculation and operando attenuated total reflectance surface-enhanced infrared absorption spectroscopy further confirmed the reaction path and mechanism of CO2-to-EtOH.

Selective Increase in CO2 Electroreduction to Ethanol Activity at Nanograin-Boundary-Rich Mixed Cu(I)/Cu(0) Sites via Enriching Co-Adsorbed CO and Hydroxyl Species.

Selective producing ethanol from CO2 electroreduction is highly demanded, yet the competing ethylene generation route is commonly more thermodynamically preferred. Herein, we reported an efficient CO2-to-ethanol conversion (53.5 % faradaic efficiency at -0.75 V versus reversible hydrogen electrode (vs. RHE)) over an oxide-derived nanocubic catalyst featured with abundant "embossment-like" structured grain-boundaries. The catalyst also attains a 23.2 % energy efficiency to ethanol within a flow cell reactor. In situ spectroscopy and electrochemical analysis identified that these dualphase Cu(I) and Cu(0) sites stabilized by grain-boundaries are very robust over the operating potential window, which maintains a high concentration of co-adsorbed *CO and hydroxyl (*OH) species. Theoretical calculations revealed that the presence of *OHad not only promote the easier dimerization of *CO to form *OCCO (ΔG~0.20 eV) at low overpotentials but also preferentially favor the key *CHCOH intermediate hydrogenation to *CHCHOH (ethanol pathway) while suppressing its dehydration to *CCH (ethylene pathway), which is believed to determine the remarkable ethanol selectivity. Such imperative intermediates associated with the bifurcation pathway were directly distinguished by isotope labelling in situ infrared spectroscopy. Our work promotes the understanding of bifurcating mechanism of CO2ER-to-hydrocarbons more deeply, providing a feasible strategy for the design of efficient ethanol-targeted catalysts.

Selective Increase in CO2 Electroreduction to Ethanol Activity at Nanograin‐Boundary‐Rich Mixed Cu(I)/Cu(0) Sites via Enriching Co‐Adsorbed CO and Hydroxyl Species

AbstractSelective producing ethanol from CO2 electroreduction is highly demanded, yet the competing ethylene generation route is commonly more thermodynamically preferred. Herein, we reported an efficient CO2‐to‐ethanol conversion (53.5 % faradaic efficiency at −0.75 V versus reversible hydrogen electrode (vs. RHE)) over an oxide‐derived nanocubic catalyst featured with abundant “embossment‐like” structured grain‐boundaries. The catalyst also attains a 23.2 % energy efficiency to ethanol within a flow cell reactor. In situ spectroscopy and electrochemical analysis identified that these dualphase Cu(I) and Cu(0) sites stabilized by grain‐boundaries are very robust over the operating potential window, which maintains a high concentration of co‐adsorbed *CO and hydroxyl (*OH) species. Theoretical calculations revealed that the presence of *OHad not only promote the easier dimerization of *CO to form *OCCO (ΔG~0.20 eV) at low overpotentials but also preferentially favor the key *CHCOH intermediate hydrogenation to *CHCHOH (ethanol pathway) while suppressing its dehydration to *CCH (ethylene pathway), which is believed to determine the remarkable ethanol selectivity. Such imperative intermediates associated with the bifurcation pathway were directly distinguished by isotope labelling in situ infrared spectroscopy. Our work promotes the understanding of bifurcating mechanism of CO2ER‐to‐hydrocarbons more deeply, providing a feasible strategy for the design of efficient ethanol‐targeted catalysts.

Rhodium-doped iron oxides promoted by sodium for highly selective hydrogenation of CO2 to ethanol and C2+ hydrocarbons

Hydrogenation of CO2 to produce high-value C2 + products has gained great interest, but catalyst design for highly selective ethanol still remains a challenge. Herein, bifunctional catalysts of iron oxide promoted with rhodium and sodium, Na-Rh-FeOx and Rh-FeOx-Na, were prepared by using simple methods of incipient wetness impregnation (IWI) and coprecipitation. The former catalyst prepared via IWI, Na-Rh-FeOx, is remarkably efficient for the hydrogenation of CO2 to ethanol with high selectivity of 91 % at 200 °C in the liquid fraction. The latter catalyst synthesized solely through the coprecipitation in a sodium-containing medium, Rh-FeOx-Na, displayed the synergy effect to perform a better CO2 conversion of 23 % at 200 °C. Characterization of catalysts via XRD, XPS, N2 physisorption, CO2-TPD, and gas pulse-chemisorption reveals that different preparation methods influenced the dispersion of sodium particles. This property, in turn, impacts the ratio of hydrogen-activating sites to CO-adsorption sites, directly related to the balance between dissociative- and non-dissociative CO* intermediates, which is crucial for ethanol formation. Adding alkali metal facilitates the formation of iron carbide Fe5C2, known to be active for C–C propagation. Integrating Na-Rh-FeOx with ZSM-5 support further increased ethanol selectivity up to 97 % in liquid phase and 90 % in gas phase. By selecting a proper route for introducing alkali metals and combining with supports, the catalyst properties can be effectively tailored, thereby regulating the catalytic activity and selectivity.

Enhanced ethanol synthesis from CO2 hydrogenation over Fe and Na co-modified Rh/CeO2 catalysts

Rh catalyst is investigated as a strong candidate for CO2 hydrogenation to ethanol, but it is still challenging because of the poor conversion efficiency. Here, by screening the promotors systematically and varying the amounts of components simultaneously, the optimized catalyst of 2Rh0.5Fe0.5Na/CeO2 was found to highly efficient catalytic CO2 hydrogenation to ethanol, giving a high ethanol selectivity of 29.8 % with a superior CO2 conversion of 13.0 % at 250 °C, 3 MPa, and the ethanol productivity reached 116.7 mmol·gRh−1·h−1. Characterization results revealed that the modification of Fe and Na, can promote the dispersion of Rh and the formation of Rh+ species, enhancing the capacities of CO2 adsorption and dissociation. In situ DRIFT experiment illuminated that the Rh active sites synergized with Fe and Na can stabilize the adsorbed species of m-CO32− and CO3H−, and promote the generation of HCOO* and CO* intermediates, which can be provided to couple with the CHx species, resulting in the high efficacy for ethanol synthesis from CO2 hydrogenation.

Critical Role of Cu Nanoparticle-Loaded Cu(100) Surface Structures on Structured Copper-Based Catalysts in Boosting Ethanol Generation in CO2 Electroreduction.

Presently, realizing high ethanol selectivity in CO2 electroreduction remains challenging due to difficult C-C coupling and fierce product competition. In this work, we report an innovative approach for improving the efficiency of Cu-based electrocatalysts in ethanol generation from electrocatalytic CO2 reduction using a crystal plane modification strategy. These novel Cu-based electrocatalysts were fabricated by electrochemically activating three-dimensional (3D) flower-like CuO micro/nanostructures grown in situ on copper foils and modifying with surfactants. It was demonstrated that the fabricated Cu-based electrocatalyst featured a predominantly exposed Cu(100) surface loaded with high-density Cu nanoparticles (NPs). The optimal Cu-based electrocatalyst displayed considerably improved CO2 electroreduction performance, with a Faraday efficiency of 37.9% for ethanol and a maximum Faraday efficiency of 68.0% for C2+ products at -1.4 V vs RHE in an H-cell, accompanied by a high current density of 69.9 mA·cm-2, much better than the particulate Cu-based electrocatalyst. It was unveiled that the Cu(100)-rich surface of nanoscale petals with abundant under-coordinated copper atoms from CuNPs was conducive to the formation and stabilization of key *CH3CHO and *OC2H5 intermediates, thereby promoting ethanol generation. This study highlighted the critical role of CuNP-loaded Cu(100) surface structures on structured Cu-based electrocatalysts in enhancing ethanol production for the CO2 electroreduction process.

Boosting Solar‐Driven CO2 Conversion to Ethanol via Single‐Atom Catalyst with Defected Low‐Coordination Cu‐N2 Motif

AbstractCu‐based catalysts have been shown to selectively catalyze CO2 photoreduction to C2+ solar fuels. However, they still suffer from poor activity and low selectivity. Herein, we report a high‐performance carbon nitride supported Cu single‐atom catalyst featuring defected low‐coordination Cu‐N2 motif (Cu‐N2‐V). Lead many recently reported photocatalysts and its Cu‐N3 and Cu‐N4 counterparts, Cu‐N2‐V exhibits superior photocatalytic activity for CO2 reduction to ethanol and delivers 69.8 μmol g−1 h−1 ethanol production rate, 97.8 % electron‐based ethanol selectivity, and a yield of ~10 times higher than Cu‐N3 and Cu‐N4. Revealed by the extensive experimental investigation combined with DFT calculations, the superior photoactivity of Cu‐N2‐V stems from its defected Cu‐N2 configuration, in which the Cu sites are electron enriched and enhance electron delocalization. Importantly, Cu in Cu‐N2‐V exist in both Cu+ and Cu2+ valence states, although predominantly as Cu+. The Cu+ sites support the CO2 activation, while the co‐existence of Cu+/Cu2+ sites are highly conducive for strong *CO adsorption and subsequent *CO‐*CO dimerization enabling C−C coupling. Furthermore, the hollow microstructure of the catalyst also promotes light adsorption and charge separation efficiency. Collectively, these make Cu‐N2‐V an effective and high‐performance catalyst for the solar‐driven CO2 conversion to ethanol. This study also elucidates the C‐C coupling reaction path via *CO‐*CO to *COCOH and rate‐determining step, and reveals the valence state change of partial Cu species from Cu+ to Cu2+ in Cu‐N2‐V during CO2 photoreduction reaction.

Boosting Solar-Driven CO2 Conversion to Ethanol via Single-Atom Catalyst with Defected Low-Coordination Cu-N2 Motif.

Cu-based catalysts have been shown to selectively catalyze CO2 photoreduction to C2+ solar fuels. However, they still suffer from poor activity and low selectivity. Herein, we report a high-performance carbon nitride supported Cu single-atom catalyst featuring defected low-coordination Cu-N2 motif (Cu-N2-V). Lead many recently reported photocatalysts and its Cu-N3 and Cu-N4 counterparts, Cu-N2-V exhibits superior photocatalytic activity for CO2 reduction to ethanol and delivers 69.8 μmol g-1 h-1 ethanol production rate, 97.8 % electron-based ethanol selectivity, and a yield of ~10 times higher than Cu-N3 and Cu-N4. Revealed by the extensive experimental investigation combined with DFT calculations, the superior photoactivity of Cu-N2-V stems from its defected Cu-N2 configuration, in which the Cu sites are electron enriched and enhance electron delocalization. Importantly, Cu in Cu-N2-V exist in both Cu+ and Cu2+ valence states, although predominantly as Cu+. The Cu+ sites support the CO2 activation, while the co-existence of Cu+/Cu2+ sites are highly conducive for strong *CO adsorption and subsequent *CO-*CO dimerization enabling C-C coupling. Furthermore, the hollow microstructure of the catalyst also promotes light adsorption and charge separation efficiency. Collectively, these make Cu-N2-V an effective and high-performance catalyst for the solar-driven CO2 conversion to ethanol. This study also elucidates the C-C coupling reaction path via *CO-*CO to *COCOH and rate-determining step, and reveals the valence state change of partial Cu species from Cu+ to Cu2+ in Cu-N2-V during CO2 photoreduction reaction.

Insights Into the one‐Step Dimethyl Ether Carbonylation to Ethanol Over Cu/ZnO@Cu‐MOR Core‐Shell Catalysts with Porogen Engagement

AbstractThis study investigates the one‐step ethanol synthesis from dimethyl ether and syngas using the catalysts combining Cu/ZnO oxides and modified Cu‐MOR zeolite. In addition to physically mixed two‐component catalysts, multifunctional catalysts featuring a Cu/ZnO core and modified zeolite (Cu‐MOR and HMOR) shell are also presented. Further, the porogenic agent of dihexadecyldimethylammonium bromide (DHAB) was involved in the synthesis process of the MOR zeolite components of Cu/ZnO@Cu‐MOR and Cu/ZnO/Cu‐MOR catalysts, but not in that of Cu/ZnO@Cu‐MOR° catalyst. A series of characterization measures including XRD, TGA, BET, SEM, TEM and EDS have been systematically studied on the prepared catalysts. Characterizations of the catalyst surface structure and texturing parameters revealed a disturbance in crystallinity upon Cu insertion, facilitating syngas separation and promoting DME carbonylation while preventing undesired CO hydrogenation. The addition of DHAB as a porogen in the synthesis of zeolite shell improved specific surface area and porosity of zeolite shell, and reduced coke deposition, without leaching active metal components, resulting in enhanced reaction properties. Cu/ZnO@Cu‐MOR core‐shell catalyst showed good performance with 28.9 % DME conversion and 43.8 % selectivity for ethanol. The optimized pore structure and enhanced catalytic performance of the modification process validate the effectiveness and efficiency of this strategy.