CO2 Selectivity Research Articles

Mechanistic insight into electrochemical CO2 reduction on Mo single-atom catalyst and its hydrate: A computational study

By using density functional theory calculation, we investigated the CO2 reduction to CH4 on molybdenum-doped graphene (Mo@Gra) and identified two major paths from the HCOO* and COOH* intermediates with different onset potential. Both HCOO* and COOH* would continent hydrogenating to CH4 by an eight proton-electron coupling transfer process via HCOO path and COOH path. By the HCOO path, the formation of HCOO* is exergonic and the potential determining step (PDS) is OH* to H2O* by an endergonic process of 0.70 eV. On the other hand, the formation of COOH* from CO2* is endergonic with the same PDS and a limiting potential (UL) of –0.70 V. In addition, nitrogen coordinated Mo-graphene (Mo@3N-Gra) also illustrated for CO2 reduction and the corresponding UL is found to be –1.88 V. In addition, we also explore the mechanisms of CO2 reduction on the water pre-adsorption surface for realistic experiments. The UL required to overcome was reduced to –0.25 V for 3H2O*Mo@Gra with three H2O co-adsorption environment, suggesting the catalytic performance can be enhanced by water promotion effect. Two structures of hydrated structures, 2H2O*OH*Mo@3N-Gra and 3H2O*Mo@3N-Gra, were selected for stimulate realistic experiments. Compared to the Mo@3N-Gra catalyst, the UL reduces to –0.48 and –0.70 V for 2H2O*OH*Mo@3N-Gra and 3H2O*Mo@3N-Gra, respectively. Although, Mo-N doped graphene has better CO2 capture ability and selectivity, it needs more onset potential to produce CH4. Our calculations demonstrated that the electrocatalytic performance can be enhanced by the hydration effect.

Efficient electroreduction of CO2 into CO in flow cell with a metal-free ternary-doped porous carbon

Herein, a series of metal-free N, P, and Se ternary-doped porous carbon electrocatalysts, referred as "SePNC" as metal-free electrocatalysts, was prepared. This study shows that, the optimal electrocatalyst of SePNC-1050, which prepared at 1050 ℃, has high CO selectivity with Faraday efficiency of 94.8% for CO, and a byproduct of 5.2% H2. After continuous electrolysis for 12 h, the Faraday efficiency and current density remained relatively high, around 95.9% and 80.2% of the initial values, respectively, indicating it has long-term operation stability. This mainly due to the synergistic effect of doped N, P, and Se, as well as the high specific surface area of SePNC-1050 (970.0 m2g−1). This work would provide a good reference to develop high-performance metal-free CO2 reduction reaction (CO2RR) electrocatalysts in future.

Polyacrylate modified Cu electrode for selective electrochemical CO2 reduction towards multicarbon products

Highly selective production of value-added multicarbon (C2+) products via electrochemical CO2 reduction reaction (eCO2RR) on polycrystalline copper (Cu) remains challenging. Herein, the facile surface modification using poly (α-ethyl cyanoacrylate) (PECA) is presented to greatly enhance the C2+ selectivity for eCO2RR over polycrystalline Cu, with Faradaic efficiency (FE) towards C2+ products increased from 30.1% for the Cu electrode to 72.6% for the obtained Cu-PECA electrode at −1.1 V vs. reversible hydrogen electrode (RHE). Given the well-determined FEs towards C2+ products, the partial current densities for C2+ production could be estimated to be −145.4 mA cm−2 for the Cu-PECA electrode at −0.9 V vs. RHE in a homemade flow cell. In-situ spectral characterizations and theoretical calculations reveal that PECA featured with electron-accepting −C≡N and −COOR groups decorated onto the Cu electrode could inhibit the adsorption of *H intermediates and stabilize the *CO intermediates, given the redistributed interfacial electron density and the raised energy level of d-band center (Ed) of Cu active sites, thus facilitating the C–C coupling and then the C2+ selective production. This study is believed to be guidable to the modification of electrocatalysts and electrodes with polymers to steer the surface adsorption behaviors of reaction intermediates to realize practical eCO2RR towards value-added C2+ products with high activity and selectivity.

Stabilized ε-Fe2C catalyst with Mn tuning to suppress C1 byproduct selectivity for high-temperature olefin synthesis

Accurately controlling the product selectivity in syngas conversion, especially increasing the olefin selectivity while minimizing C1 byproducts, remains a significant challenge. Epsilon Fe2C is deemed a promising candidate catalyst due to its inherently low CO2 selectivity, but its use is hindered by its poor high-temperature stability. Herein, we report the successful synthesis of highly stable ε-Fe2C through a N-induced strategy utilizing pyrolysis of Prussian blue analogs (PBAs). This catalyst, with precisely controlled Mn promoter, not only achieved an olefin selectivity of up to 70.2% but also minimized the selectivity of C1 byproducts to 19.0%, including 11.9% CO2 and 7.1% CH4. The superior performance of our ε-Fe2C-xMn catalysts, particularly in minimizing CO2 formation, is largely attributed to the interface of dispersed MnO cluster and ε-Fe2C, which crucially limits CO to CO2 conversion. Here, we enhance the carbon efficiency and economic viability of the olefin production process while maintaining high catalytic activity.

Investigation on the hydrogen production by methanol aqueous phase reforming over Pt/CexMg1-xO2 catalyst: Synergistic effect of support basicity and oxygen vacancies

Green hydrogen production from biomass oxygenated derivatives (methanol, ethanol, ethylene glycol, etc.) by low temperature aqueous phase reforming (APR) has the advantages of high hydrogen selectivity and low energy consumption. A series of CexMg1-xO2 mixed oxide supported catalysts were synthesized by a simple citric acid combustion method. The results show that these catalysts exhibit excellent water-gas shift reaction activity and CO is rarely detected in the products, which is due to their abundant oxygen vacancies of the mixed oxide supports of the Pt/CexMg1-xO2 catalysts. At the same time, the introduction of MgO provides more strong basic sites on the surface of mixed oxide support, and the methanol conversion and hydrogen yield show a volcano peak with the increasing number of basic sites and the hydrogen production reaches the highest (127.16 mmol) over Pt/Ce0·5Mg0·5O2 catalyst. The mixed oxide supported Pt/Ce0·5Mg0·5O2 catalyst enjoys the benefits of both oxygen vacancies in accelerating H2O adsorption/dissociation and strong basic sites in contributing to the formation of formate group (HCOO*), which improve the oxidation of CO* and APR activity. This synergistic effect is conducive to improve hydrogen yield of methanol APR and reduce CO selectivity to a minimum level.

Unravelling the morphology effect of Pt/In2O3 catalysts for highly efficient hydrogen production by methanol steam reforming

Methanol steam reforming (MSR) constitutes an attractive reaction for high-yield on-board hydrogen production for H2-fueled fuel cell applications. Engineering the morphology of Pt/In2O3 heterogeneous catalyst is a feasible strategy for efficient MSR catalyst design, which can construct the Pt2+-In2O3 interfacial sites by utilizing the interaction between Pt and In2O3, thereby facilitating oxygen vacancy creation and activating methanol and water molecules. In this work, three kinds of In2O3 supports with different morphologies of nanorods, nanocubes and nanoplates were synthesized, and Pt/In2O3 catalysts were prepared by deposition–precipitation method. The performance of the catalysts for MSR hydrogen production was evaluated at 250 ∼ 375 ℃. The rod-shaped Pt/In2O3 catalyst with extremely low loading of Pt (0.21 wt%) exhibited the superior catalytic activity compared to the other two counterpart catalysts, achieving the complete CH3OH conversion and the CO selectivity as low as 3.8 % at 325 ℃. Moreover, the performance of Pt/r-In2O3 catalyst remained stable during the stability test for up to 40 h. Based on XRD, BET, HRTEM, XPS, Raman, UV–vis and H2-TPR characterization methods, the observed morphology-dependent reactivity of Pt/In2O3 catalysts can be correlated to the good low-temperature reducibility, abundant surface Pt2+ and adsorbed reactive oxygen species, which was originated from the exposed (211) crystal planes. The preferential exposed (211) crystal plane enables a stronger interaction of In2O3 support with Pt species resulting in the synergistic effect of high oxygen vacancy content, high proportion of Pt2+, and the formation of Pt2+-In2O3 interface active sites, which facilitates the activation and conversion of methanol and water molecules. The developed strategy may provide insight into the development of the design principles for high-performance methanol reforming catalysts for hydrogen production.

Dimensionally Intact Construction of Ultrathin S-Scheme CuFe2O4/ZnIn2S4 Heterojunctional Photocatalysts for CO2 Photoreduction.

The conversion of CO2 into carbon-neutral fuels such as methane (CH4) through selective photoreduction is highly sought after yet remains challenging due to the slow multistep proton-electron transfer processes and the formation of various C1 intermediates. This research highlights the cooperative interaction between Fe3+ and Cu2+ ions transitioning to Fe2+ and Cu+ ions, enhancing the photocatalytic conversion of CO2 to methane. We introduce an S-scheme heterojunction photocatalyst, CuFe2O4/ZnIn2S4, which demonstrates significant efficiency in CO2 methanation under light irradiation. The CuFe2O4/ZnIn2S4 heterojunction forms an internal electric field that aids in the mobility and separation of exciton carriers under a wide solar spectrum for exceptional photocatalytic performance. Remarkably, the optimal CuFe2O4/ZnIn2S4 heterojunction system achieved an approximately 68-time increase in CO2 conversion compared with ZnIn2S4 and CuFe2O4 nanoparticles using only pure water, with nearly complete CO selectivity and yields of CH4 and CO reaching 172.5 and 202.4 μmol g-1 h-1, respectively, via a 2-electron oxygen reduction reaction (ORR) process. The optimally designed CuFe2O4/ZnIn2S4 heterojunctional system achieved approximately 96% conversion of BA and 98.5% selectivity toward benzaldehyde (BAD). Additionally, this photocatalytic system demonstrated excellent cyclic stability and practical applicability. The photogenerated electrons in the CuFe2O4 conduction band enhance the reduction of Fe3+/Cu2+ to Fe2+/Cu+, creating a microenvironment conducive to CO2 reduction to CO and CH4. Simultaneously, the appearance of holes in the ZnIn2S4 valence band facilitates water oxidation to O2. The synergistic function within the CuFe2O4/ZnIn2S4 heterojunction plays a pivotal role in facilitating charge transfer, accelerating water oxidation, and thereby enhancing CO2 reduction kinetics. This study offers valuable insights and a strategic framework for designing efficient S-scheme heterojunctions aimed at achieving carbon neutrality through solar fuel production.

Efficient Low-Pressure CO2 capture via ZIF-8 modified by deep eutectic solvents

To enhance CO2 sorption efficiency under low-pressure conditions and effectively compete with N2 sorption in flue gas, modifications are implemented aimed at improving the adsorption capacity and selectivity of ZIF-8, renowned for their robust stability. Deep eutectic solvent (DES) comprising tetraethylammonium chloride (TEAC), tetrapropylammonium chloride (TPAC), and tetrabutylammonium bromide (TBAB) as hydrogen-bond acceptors, along with ethanolamine (MEA) as the hydrogen-bond donor, were meticulously prepared for this purpose. ZIF-8 underwent modification through DES loading, resulting in the distinctive emergence of a “core-membrane” structure. Characterization revealed that the DES effectively adhered to the surface of ZIF-8 in a membrane-like structure, without altering the chemical structure or pore size of ZIF-8. The most significant enhancement in sorption capacity was observed with TPAC&MEA modification. Considering the presence of N2 partial pressure in the flue gas, at 0.05 and 1 bar, the CO2 adsorption capacities reached 1.92 and 3.03 mmol g−1, respectively, increasing 71.11 and 4.00 times compared to pristine ZIF-8. The ZIF-8 exhibited a CO2/N2 separation coefficient of 72.77, which increased to a maximum of 997.50 after DES modification. Additionally, the modified material demonstrated exceptional cyclic and thermal stability during testing. This study significantly elevates the CO2 adsorption capacity and selectivity of solid materials within the low-pressure range, providing pivotal support for CO2 capture and decarbonization efforts.

Monitoring of CO2 using MWCNTs functionalized clay porous composite for clean room facility

In this current work, a vastly sensitive, selective, and cost-effective CO2 gas sensor was developed by utilizing MWCNTs doped clay ceramics, for the developments in clean room facilities or pharmaceutical purposes. Herein, MWCNTs functionalized clay composites (CTsX; X = 0, 5, 10, and 15) were prepared by a bottom up approach i.e. solid-state reaction method and characterized by SEM with EDAX, XPS, XRD, FTIR, UV–visible spectroscopy, BET, and sensing. SEM micrographs revealed the created pores and grown nanotubes within the base material. XPS demonstrated some sites of Oads deficiencies, attributed to the expediting of sensing phenomena. Further, MWCNTs are well functionalized with clay as confirmed via XRD phases such as SiO2 (trigonal), AlKSi3O8 (monoclinic), Al2CaSi2O8 (triclinic) and C2Ca5Si2O13 (monoclinic). Furthermore, BET established the mesoporous nature of CTs15 composite having mean pore size ∼ 3.82 nm, also CO2 gas (200–1000 ppm) was tested at ambient temperature. Moreover, CTs15 composite showed maximum sensor response (S.R.) 5.31 at 1000 ppm of CO2 gas, whereas minimum response/recovery time (Tres./Trec.) 10.87/8.93 s were noticed at 200 ppm while operated at 28℃ (ambient condition). Additionally, LOD assured 217 ppm, which suggests that fabricated sensor is highly sensitive and selective for CO2, and may be used for clean room services. Therefore, this cost effective and eco-friendly composite is suitable for monitoring of CO2 gas for indoor and outdoor environments within a few seconds of Tres. and Trec..

High-throughput screening of single-atom catalysts on 1 T-TMD for highly active and selective CO2 reduction reaction: Computational and machine learning insights

The study of transition metals and various possible surface compositions has sparked great interest in low-cost materials, which exhibit high activity and selectivity in catalysis. While various single-atom catalysts loaded on transition metal dichalcogenide (TMD) substrates with excellent CO2 reduction performance have been identified, the relationship between catalytic activity and the intrinsic properties of TMD single-atom catalysts remains unclear. Hence, a high-throughput first-principle computational approach is proposed to screen 24 transition metals anchored on 8 TMD monolayers to determine their catalytic activity in CO2RR. The results show that Fe@CoS2, Pt@TiTe2 and Co@CoS2 exhibit exceptional performances with low CO2RR limiting-potentials of −0.045 eV, 0.75 eV, and 0.54 eV, respectively, showcasing selective pathways towards formic acid (HCOOH), methane (CH4), and methanol (CH3OH). Employing the Sure Independence Screening and Sparsifying Operator method(SISSO), key descriptors linking the performance of single-atom catalysts with their intrinsic features are identified, providing insights for the discovery of superior CO2RR catalysts. Moreover, it was observed that a feature of the anchored single atom, the difference between covalent radius and atomic radius (CR-R), is associated with multiple crucial reaction steps, exhibiting a strong linear relationship with the charge transfer of *COOH. This work not only identifies promising CO2RR catalysts but also establishes a predictive framework for screening catalysts based on their intrinsic properties, paving the way for future advancements in CO2 reduction research.

Controllable preparation of metal oxide nanoparticles and Ni/CeO2 catalysts by microdroplets extraction and separation technology in mini-channel

The microreactor coupled mini-channel microdroplets extraction and separation technology (MES) was developed by adding polyvinyl alcohol (PVA) into microdroplets, realizing the controllable synthesis of a series of mono-component and multi-component metal oxide nano particles (MONPs). A double-layer surfactant structure composed of Span20 (oil phase surfactant) and PVA (water phase surfactant) was designed as a barrier to intercept and collect the precipitated salt at the microdroplet interface, the addition of PVA reduces the loss of salt components during the extraction process from 41.7 wt% to 1.1 wt%. The size control of mono-component MONPs (CuO, Co3O4, and NiO) was achieved using MES method. Furthermore, in the application direction of preparing multi-component MONPs, the advantages of MES in preparing multi-component catalysts (Ni/CeO2) were verified. TEM, XRD, H2-TPR, CO2-TPD, XPS, BET et al. characterizations have shown that Ni entered the lattice of CeO2 during precipitation to form a Ni-O-Ce solid solution and was therefore highly dispersed in CeO2. Ni/CeO2-MES showed high CO2 conversion and CO selectivity in reverse water gas shift (RWGS) testing compared to Ni/CeO2 catalysts prepared by impregnation method which has excellent thermal stability and can maintain over 99 % CO selectivity even after 50 h of reaction at 600 °C. The MES method was proved to be an efficient synthesis technology for MONPs and can be extended to a variety of metal oxides catalysts.

Bimetallic oxide electrocatalyst with interfacial structure for enhanced electrocatalytic CO2 reduction

The development of electrochemical carbon dioxide reduction reaction (eCO2RR) electrocatalysts with high selectivity, high activity, low cost and high enrichment is an important research direction. We report a bimetallic oxide (CuO-Sb2O3) nanocomposite catalyst with interfacial structure formed by modifying CuO with Sb2O3 to enhance CO2 reduction. The CO faraday efficiency (FE) of CuO-Sb2O3 reaches 96.2 % in a CO2-saturated KHCO3 electrolyte at −1.05 V vs. RHE, which is better than that of pure CuO (28.2 %) and pure Sb2O3 (0 %, hydrogen only). In addition, CuO-Sb2O3 with an interfacial structure presents good stability. The increased activity of eCO2RR in producing CO is due to the unique surface and interfacial structure to capture CO2, and interfacial distortions and oxygen vacancies in its internal CuO and Sb2O3, which can provide more active centers and larger electrochemical active surface area (ECSA) to provide electron transfer and promote the formation of CO products. Besides, the interfacial effect for strong adsorption of *COOH and desorption of *CO improves the selectivity of CO.

Fabrication of Nickel Single Atoms with Ionic Liquids by Only One-Step Pyrolysis for CO2 Electroreduction.

Single-atom catalysts (SACs) are appealing for carbon dioxide (CO2) electroreduction with the utmost advantages; however, their preparation is still challenging because of the complicated procedure. Here, a novel Ni-based single-atom catalyst (Ni-BB-BD) is constructed from raw materials, [BMIM]BF4, [BMIM]DCN, and NiCl2·6H2O, directly without any precursor by only one-step pyrolysis. Ni-BB-BD achieves a maximum carbon monoxide Faradaic efficiency (FECO) of 96.5% at -0.8 V vs RHE, as well as long-term stability over 16 h. High current density up to -170.6 mA cm-2 at -1.0 V vs RHE is achieved in the flow cell along with a CO selectivity of 97.7%. It is identified that [BMIM]BF4 is the nitrogen source, while [BMIM]DCN is mainly taken as the carbon source. Theoretical studies have revealed that the rich nitrogen content, especially for the uncoordinated nitrogen, plays a critical role in lowering rate-limiting barrier height. This work develops a facile and effective strategy to prepare the SACs.

An adsorption micro mechanism theoretical study of CO2-rich industrial waste gas for enhanced unconventional natural gas recovery: Comparison of coalbed methane, shale gas, and tight gas

Direct injection of CO2-rich industrial waste gas to displace unconventional natural gas is proposed as an energy-saving and green development method. In this work, the Giant canonical Monte Carlo and molecular dynamics methods were employed to compare the adsorption mechanisms of this method in three typical unconventional gas reservoirs, which are coal seam, shale and tight sandstone. It is found in the adsorption configurations that the proportion of gas molecules in the free state is higher in tight sandstone than in shale and coal seam. The adsorption energy of CH4/waste gas components on all reservoirs is in the order of CH4/SO2 > CH4/CO2 > CH4/NO > CH4/N2, among which the absolute value of the CH4/SO2 adsorption energy on the coal seam reaches the highest 64.220 kJ/mol. The adsorption selectivity of SO2, CO2 and NO over CH4 is greater than 1.0 in all reservoirs at depths of 0.5–4.0 km, and the competitive adsorption phenomenon in the deep reservoirs has a severe negative effect on it. Gas adsorption mode in the tight sandstone is dominated by filling pore structures, while gas adsorption in the coal seam is highly correlated with adsorption sites. This study is instructive for enhanced unconventional natural gas recovery by CO2-rich industrial waste gas injection from the perspective of gas adsorption.

Selective CO2 adsorption over a Zr-based metal–organic framework functionalized with tris(2-aminoethyl)amine

Selective capture of CO2 from off-gas or even the atmosphere is very important against global warming. In this work, a stable Zr-based MOF (MOF-808) was loaded with –COOH group and was further functionalized with tris(2-aminoethyl)amine (TREN), via a reaction between –NH2 of TREN and –COOH sites. The derived materials were analyzed with X-ray diffraction, scanning electron microscopy, FTIR, X-ray photoelectron spectroscopy, thermogravimetry analysis, elemental analysis, and nitrogen adsorption at 77 K; utilized in the adsorption of CO2 and N2 at relatively low pressure up to 100 kPa. One functionalized MOF-808 prepared in this work (named MOF808-EDTA-TREN(0.3)) showed remarkable performances in the selective capture of CO2 under low pressure. For example, the invented MOF exhibited the highest selectivity (based on ideal adsorbed solution theory) in CO2 capture from N2 and CO2 (SCO2/N2: 519 at 100 kPa) compared with any reported results, thus far, using MOF-808-based materials. Moreover, MOF808-EDTA-TREN(0.3) was recyclable up to the fifth run upon vacuum treatment. The noticeable performances of MOF808-EDTA-TREN(0.3) in CO2 adsorption could be explained by the loaded –NH2 sites of TREN (that are effective in carbamates formation) and bulky TREN that decreases the nitrogen adsorption because of the reduced porosity of the MOF. In brief, loading bulky amines with ample amino groups like TREN can be suggested as an attractive way to modify a MOF for selective CO2 capture from off-gas of various industries.

Effects of B-site Co3+ doping on physicochemical characteristics and hydrogen production performance of novel LaCuxCo1-xO3 perovskite coated on monolithic catalyst in methanol steam reforming

A series of B-site Co3+-doped LaCuxCo1-xO3 (x = 1, 0.8, 0.6, 0.4, 0.2) perovskites were synthesized by solution combustion method and their physicochemical properties were comprehensively characterized. The perovskite-coated Cu foams were applied as monolithic catalysts for methanol steam reforming to produce H2. Results showed that an appropriate amount of Co3+ doping led to the stabilization of crystal structure, the reduction of particle size, the improvement of chemical constitution, the enhancement of reduction behavior, the decrease of acidity, the increase of specific surface area, and the optimization of surface chemical state. The monolithic catalyst loaded with LaCu0.4Co0.6O3 showed the highest methanol conversion rate and H2 production rate, the lowest CO selectivity, the best stability and the lowest carbon deposition. However, excess Co3+ resulted in a degradation of the catalytic performance. The findings of this work suggested that introducing Co3+ might be a promising way to enhance the activity of Cu species for obtaining a better Cu-containing perovskite-based monolithic catalyst.

Using phosphonic acid monolayers to control CO2 adsorption and hydrogenation onPt/Al2O3

Phosphonic acid (PA) self‐assembled monolayers (SAMs) were deposited onto Pt/Al2O3 catalysts to enable control over CO2 adsorption and CO2 hydrogenation activity. Significant differences in catalytic activity toward CO2 hydrogenation (reverse water‐gas shift, RWGS) were observed after coating Al2O3 with PAs, suggesting that the reaction was mediated by CO2adsorption on the support. Amine‐functionalized PAs were found to outperform their alkyl counterparts in terms of activity, however there was little effect of amine location in the SAM (i.e., spacing between the amine functional group and phosphonate attachment group). One amine‐PA and one alkyl‐PA, aminopropyl phosphonic acid (C3NH2PA) and methyl phosphonic acid (C1PA), respectively, were investigated in more detail. The C3NH2PA‐modified catalyst was found to bind CO2 as a combination of carbamate and bicarbonate. Additionally, at 30 °C, both PAs were found to reduce CO2 adsorption uptake by approximately 50% compared to unmodified 5%Pt/Al2O3. CO2 adsorption enthalpy was measured for the catalysts and found to be strongly correlated with hydrogenation activity, with the trend in binding enthalpy and CO2 hydrogen rate trending as uncoated > C3NH2PA > C1PA. PA SAMs were found to have weaker effects on CO binding and CO selectivity, consistent with selective modification of the Al2O3support by the PAs.

Ethylene Electrosynthesis via Selective CO2 Reduction: Fundamental Considerations, Strategies, and Challenges

AbstractThe electrochemical carbon dioxide reduction reaction (CO2RR) is a promising approach for reducing atmospheric carbon dioxide (CO2) emissions, allowing harmful CO2 to be converted into more valuable carbon‐based products. On one hand, single carbon (C1) products have been obtained with high efficiency and show great promise for industrial CO2 capture. However, multi‐carbon (C2+) products possess high market value and have demonstrated significant promise as potential products for CO2RR. Due to CO2RR's multiple pathways with similar equilibrium potentials, the extended reaction mechanisms necessary to form C2+ products continue to reduce the overall selectivity of CO2‐to‐C2+ electroconversion. Meanwhile, CO2RR as a whole faces many challenges relating to system optimization, owing to an intolerance for low surface pH, systemic stability and utilization issues, and a competing side reaction in the form of the H2 evolution reaction (HER). Ethylene (C2H4) remains incredibly valuable within the chemical industry; however, the current established method for producing ethylene (steam cracking) contributes to the emission of CO2 into the atmosphere. Thus, strategies to significantly increase the efficiency of this technology are essential. This review will discuss the vital factors influencing CO2RR in forming C2H4 products and summarize the recent advancements in ethylene electrosynthesis.

Insights into catalytic oxidation mechanism of toluene by lanthanum mangan-based perovskite in wet environment based on in-situ DRIFTS

This paper investigated that the catalytic activity and CO2 selectivity of LaMnO3, La0.9Ca0.1MnO3 and 3-La0.9Ca0.1MnO3 catalysts with different oxygen vacancy concentrations were compared under wet and dry conditions. The 3-La0.9Ca0.1MnO3 catalysts had excellent water resistance. The presence of H2O had less effect on toluene conversion than on CO2 selectivity. In wet environment, the 3-La0.9Ca0.1MnO3 catalyst achieved 90 % toluene conversion at 173 °C, but less than 20 % selectivity for CO2 at this time, and reached 90 % selectivity for CO2 at 220 °C. The effect of H2O on the catalytic oxidation mechanism of toluene was analyzed by in-situ DRIFTS analysis. The presence of H2O could promote the decomposition of toluene into intermediates of benzyl alcohol, benzoic acid, benzaldehyde and maleic anhydride at low temperature (50 °C), but the intermediates were difficult to decompose into CO2 and H2O. It was suggested that surface hydroxyl group could promote the transformation of toluene to intermediate at low temperature, and suitable oxygen vacancies and surface hydroxyl group could jointly promote the transformation of toluene to ideal product. This work provided a theoretical basis for the design of water-resistant catalysts in industry.

Frustrated Lewis pairs on Al-doped CeO2 for efficient reverse water–gas shift reaction

The reverse water–gas shift (RWGS) reaction holds promise for producing high value-added CO from CO2, serving as a crucial intermediate to feedstock for producing various hydrocarbons through Fischer-Tropsch synthesis reactions. Metallic catalysts often yield significant methane production as a by-product during operation, whereas non-metallic oxide catalysts offer potential for high CO selectivity. We prepare Al doped CeO2 nanorod by atomic layer deposition (ALD). The incorporation of Al creates more oxygen vacancies on the surface, resulting in increased Frustrated Lewis Pair (FLP) sites. Particularly, the CO yield of ALD-modified CeO2 was enhanced by 134 % compared to that of pristine CeO2 nanorods (CeO2-NR) at 500 °C, with CO selectivity reached 100 %. Density Functional Theory (DFT) calculations reveal a lower energy barrier for H2 dissociation facilitated by the formation of FLP sites, potentially leading to heightened activity in the Reverse Water Gas Shift (RWGS) reaction.