C2 Products Research Articles

Steering the Site Distance of Atomic Cu−Cu Pairs by First‐Shell Halogen Coordination Boosts CO2‐to‐C2 Selectivity

AbstractElectrocatalytic reduction of CO2 into C2 products of high economic value provides a promising strategy to realize resourceful CO2 utilization. Rational design and construct dual sites to realize the CO protonation and C−C coupling to unravel their structure‐performance correlation is of great significance in catalysing electrochemical CO2 reduction reactions. Herein, Cu−Cu dual sites with different site distance coordinated by halogen at the first‐shell are constructed and shows a higher intramolecular electron redispersion and coordination symmetry configurations. The long‐range Cu−Cu (Cu−I−Cu) dual sites show an enhanced Faraday efficiency of C2 products, up to 74.1 %, and excellent stability. In addition, the linear relationships that the long‐range Cu−Cu dual sites are accelerated to C2H4 generation and short‐range Cu−Cu (Cu−Cl−Cu) dual sites are beneficial for C2H5OH formation are disclosed. In situ electrochemical attenuated total reflection surface enhanced infrared absorption spectroscopy, in situ Raman and theoretical calculations manifest that long‐range Cu−Cu dual sites can weaken reaction energy barriers of CO hydrogenation and C−C coupling, as well as accelerating deoxygenation of *CH2CHO. This study uncovers the exploitation of site‐distance‐dependent electrochemical properties to steer the CO2 reduction pathway, as well as a potential generic tactic to target C2 synthesis by constructing the desired Cu−Cu dual sites.

Exploring C1-C3 variations and Fischer–Tropsch chemistry via electrochemical CO2 reduction on electrodeposited Cu/Ag and Ag/Cu electrodes

Ag and Cu bimetallic electrodes are extensively studied for producing C-C coupled C2+ reduction products through electrochemical CO2 reduction. In this study, we prepared electrodes with Cu electrodeposited on Ag supports (CuED/Ag) and Ag electrodeposited on Cu supports (AgED/Cu) via electrodeposition, demonstrating behaviors for reduction products under various electrochemical conditions. The products were categorized as H2, C1 (CO, CH4, formate, methanol), C2 (C2H4, ethanol, acetate, acetaldehyde, glycolaldehyde, and ethylene glycol), C3 (propanol, isopropanol), and Fischer–Tropsch (F-T) synthesis products (CnH2n and CnH2n+2, n ≥ 2). Notably, ethylene glycol was only observed over AgED/Cu. The reduction products dynamically changed with applied potentials and electrolyte concentrations. The mechanism was understood to involve surface H* adsorption, CO2 adsorption, C-C coupling, hydrogenation, and dehydration. Minor F-T synthesis chemistry was observed, explained by *CO and *CH2 insertion chain growth. The distinct product behaviors over the CuED/Ag and AgED/Cu electrodes provide valuable insights into the development of electrodes for producing value-added carbon products via CO2 utilization.

In Situ Surfaced Mn-Mn Dimeric Sites Dictate CO Hydrogenation Activity and C2 Selectivity over MnRh Binary Catalysts.

Massive ethanol production has long been a dream of human society. Despite extensive research in past decades, only a few systems have the potential of industrialization: specifically, Mn-promoted Rh (MnRh) binary heterogeneous catalysts were shown to achieve up to 60% C2 oxygenates selectivity in converting syngas (CO/H2) to ethanol. However, the active site of the binary system has remained poorly characterized. Here, large-scale machine-learning global optimization is utilized to identify the most stable Mn phases on Rh metal surfaces under reaction conditions by exploring millions of likely structures. We demonstrate that Mn prefers the subsurface sites of Rh metal surfaces and is able to emerge onto the surface forming MnRh surface alloy once the oxidative O/OH adsorbates are present. Our machine-learning-based transition state exploration further helps to resolve automatedly the whole reaction network, including 74 elementary reactions on various MnRh surface sites, and reveals that the Mn-Mn dimeric site at the monatomic step edge is the true active site for C2 oxygenate formation. The turnover frequency of the C2 product on the Mn-Mn dimeric site at MnRh steps is at least 107 higher than that on pure Rh steps from our microkinetic simulations, with the selectivity to the C2 product being 52% at 523 K. Our results demonstrate the key catalytic role of Mn-Mn dimeric sites in allowing C-O bond cleavage and facilitating the hydrogenation of O-terminating C2 intermediates, and rule out Rh metal by itself as the active site for CO hydrogenation to C2 oxygenates.

Efficient CO2 reduction to C2 products in a Ce-TiO2 photoanode-driven photoelectrocatalysis system using a Bnanometer Cu2O cathode

Excessive emission of CO2 into the atmosphere has caused significant environmental issues. Photoelectrocatalytic (PEC) reduction of CO2 is an effective method that combines the benefits of both photo- and electrocatalysis. This process effectively minimizes CO2 emissions, enhances the efficiency of CO2 reduction, and diminishes energy consumption during the reduction process. In this work, we have successfully developed a photoelectrochemical (PEC) system, integrating a Ce-doped TiO2 film as the photoanode and Cu2O as the dark cathode, in which the 4 % Ce-TiO2 film photoanode demonstrated the best performance. Electrochemical performance data revealed that the Cu2O catalysts, characterized by their octahedral geometry that optimally presents active sites for CO2 reduction, displayed superior activity in converting CO2. Through a straightforward hydrothermal synthesis, we crafted three-dimensional, flower-like TiO2 thin films. The strategic incorporation of cerium into the TiO2 matrix not only enhanced the material's crystallinity but also resulted in a uniform and compact morphology. This modification significantly narrowed the band gap of TiO2, thereby boosting its photocatalytic capabilities. In the system where a 4 % Ce-TiO2 thin film photoanode was used to drive the PEC reduction of CO2, the octahedral Cu2O catalyst demonstrated the highest selectivity for C2 products. This occurred at a reaction voltage of −1.4 V vs. RHE, resulting in a total Faraday efficiency of 67.33 %. Notably, this Faraday efficiency is double the one produced from the electrocatalytic (EC) system. This work demonstrates that the use of a 4 % Ce-TiO2 film as a photoanode is able to solve the photocorrosion problem of the Cu2O catalyst while employing a photovoltaic combination to enhance the selectivity to C2 products.

Highly Active Photoreduction of Atmospheric-Concentration CO2 into CH3COOH over Palladium Particles on Nb2O5 Nanosheets.

The endeavor to drive CO2 photoreduction towards the synthesis of C2 products is largely thwarted by the colossal energy hurdle inherent in C-C coupling. Herein, we load active metal particles on metal oxide nanosheets to build the dual metal pair sites for steering C-C coupling to form C2 products. Taking Pd particles anchored on the Nb2O5 nanosheets as an example, the high-angle annular dark-field image and X-ray photoelectron spectroscopy demonstrate the presence of Pd-Nb metal pair sites on the Pd-Nb2O5 nanosheets. Density functional theory calculations reveal these sites exhibit a low reaction energy barrier of only 1.02 eV for C-C coupling, implying that the introduction of Pd particles effectively tailors the reaction step to form C2 products. Therefore, the Pd-Nb2O5 nanosheets achieve a CH3COOH evolution rate of 13.5 μmol g-1 h-1 in photoreduction of atmospheric-concentration CO2, outshining all other single photocatalysts reported to date under analogous conditions.

Surface fluorination of BiVO4 for the photoelectrochemical oxidation of glycerol to formic acid

The C–C bond cleavage of biomass-derived glycerol to generate value-added C1 products remains challenging owing to its slow kinetics. We propose a surface fluorination strategy to construct dynamic dual hydrogen bonds on a semiconducting BiVO4 photoelectrode to overcome the kinetic limit of the oxidation of glycerol to produce formic acid (FA) in acidic media. Intensive spectroscopic characterizations confirm that double hydrogen bonds are formed by the interaction of the F–Bi–F sites of modified BiVO4 with water molecules, and the unique structure promotes the generation of hydroxyl radicals under light irradiation, which accelerates the kinetics of C–C bond cleavage. Theoretical investigations and infrared adsorption spectroscopy reveal that the double hydrogen bond enhances the C=O adsorption of the key intermediate product 1,3-dihydroxyacetone on the Bi–O sites to initiate the FA pathway. We fabricated a self-powered tandem device with an FA selectivity of 79% at the anode and a solar-to-H2 conversion efficiency of 5.8% at the cathode, and these results are superior to most reported results in acidic electrolytes.

Sn-modified Cu nanosheets catalyze CO2 reduction to C2H4 efficiently by stabilizing CO intermediates and promoting C[sbnd]C coupling

Electrocatalytic CO2 reduction reaction (CO2RR) is a process in which CO2 is reduced to high-value-added C1 and C2 energy sources, particularly ethylene (C2H4), thereby supporting carbon–neutral recycling with minimal consumption. This makes it a promising technology with significant potential. Nevertheless, the low selectivity for C2H4 remains a significant challenge in practical applications. In this paper, a strategy based on Cu–Sn bimetallic catalysts is proposed to improve the selectivity of electrocatalytic conversion of CO2 to C2H4 over Cu-based catalysts. The experimental results show that the Faradaic efficiency (FE) of C2H4 can reach up to 48.74 %, and the FE of C2 product reaches 60 %, at which time the local current density is 11.99 mA/cm2. Compared with pure Cu catalyst, the FE and local current density of C2H4 increased by 55.27 % and 35.33 %, respectively. Moreover, the FE of C2H4 remained above 40 % after 8 h over Cu10-Sn catalyst. The addition of Sn facilitates the transfer of local electrons from Cu to Sn, stabilizes the *CO intermediate, promotes CC coupling, significantly lowers the reaction energy barrier, and enables highly efficient CO2RR catalysis for C2H4 production.

Theoretical investigation of sustainable CO2 electroreduction to high-value products utilizing N-doped/BN-modified Triphenylene-Graphdiyne catalysts

The potential of carbon-based triphenylene-graphdiyne (tpGDY) and its derivatives for the electrochemical CO2 reduction reaction (eCO2R) was comprehensively explored using density functional theory (DFT) calculations. Six variants were studied: pristine tpGDY, tpGDY-BN, tpGDY-N01, tpGDY-N02, tpGDY-N08, and tpGDY-BN-B01. Pristine tpGDY, tpGDY-BN, and tpGDY-N08 exhibited exceptional catalytic activity, efficiently converting CO2 into CO and HCOOH without external energy input. Significantly, N-doped tpGDY catalysts incorporating sp2-hybridized nitrogen atoms at the acetylenic sites (tpGDY-N01 and tpGDY-BN-N01) demonstrated remarkable electrocatalytic activity for the targeted conversion of CO2 to CH3OH. This outstanding performance is further corroborated by the low limiting potentials of −0.18 V and −0.27 V for tpGDY-N01 and tpGDY-BN-N01, respectively, highlighting their economic viability. Furthermore, the feasibility of C2 production (e.g., C2H5OH, C2H4 and C2H6) through C–C coupling of *CHO+*CO intermediate was investigated for tpGDY-N01 and tpGDY-BN-N01. DFT calculations suggest these pathways are achievable but require potentials of 0.84 V and 0.71 V for tpGDY-N01 and tpGDY-BN-N01, respectively. This study demonstrates the efficacy of N-doped tpGDY as a metal-free electrocatalyst for CO2 reduction, enabling the generation of both C1 and C2 products. This discovery holds significant promise for the advancement of sustainable CO2 conversion technologies.

Evaluating diffusivity for efficient electrocatalytic conversion of carbon dioxide into multicarbon products using dealloyed hierarchically nanoporous copper

Hierarchical nanoporous copper (Hi-NPC) is a promising catalyst for carbon dioxide reduction reaction (CO2RR) due to its high surface area and excellent mass transport properties. To evaluate the effect of its architecture, eutectic-phased Cu18Al82 and single-phased Cu33Al67 were potentiostatically dealloyed to produce Hi-NPC and homogeneous nanoporous copper (Ho-NPC), respectively. At a comparable overpotential, the Hi-NPC electrocatalyst exhibited a significantly higher C2+ partial current density (jC2+) in CO2RR, reaching 510 mA/cm2, compared to both Ho-NPC (72 mA/cm2) and Cu electrodes (23 mA/cm2). When the current density was normalized by the electrochemically active surface area, the CO production among three electrodes demonstrated similar electrochemical behavior. However, notable differences were observed in the formation of C2H4 and C2H5OH, which can be attributed to the hierarchical structure of Hi-NPC facilitating C–C coupling to form C2 products. Although the Tafel plot indicated the CO2RR kinetics were identical for all three electrodes, linear sweep voltammetry experiments revealed that Hi-NPC exhibited the steepest current variation slope. Furthermore, the improved diffusivity was further confirmed by conducting oxygen reduction reactions with varying partial O2/N2 flow rates and electrochemical impedance spectroscopies. The hydrophobic properties of the electrode under various CO2RR current densities were also evaluated by water contact angle test.

Recent progress in solar-driven CO2 reduction to multicarbon products.

Currently, most catalysts used for photoconverting carbon dioxide (CO2) typically produce C1 products. Achieving multicarbon (C2+) products, which are highly desirable due to their greater energy density and economic potential, still remains a significant challenge. This difficulty is primarily due to the kinetic hurdles associated with the C-C coupling step in the process. Given this, devising diverse strategies to accelerate C-C coupling for generating multicarbon products is requisite. Herein, we first give a classification of catalysts involved in the photoconversion of CO2 to C2+ fuels. We summarize metallic oxides, metallic sulfides, MXenes, and metal-organic frameworks as catalysts for CO2 photoreduction to C2+ products, attributing their efficacy to the inherent dual active sites facilitating C-C coupling. In addition, we survey covalent organic frameworks, carbon nitrides, metal phosphides, and graphene as cocatalysts for CO2 photoreduction to C2+ products, owing to the incorporated dual active sites that induce C-C coupling. In the end, we provide a brief conclusion and an outlook on designing new photocatalysts, understanding the catalytic mechanisms, and considering the practical application requirements for photoconverting CO2 into multicarbon products.

Leaf-like MSX/TiN heterojunction photocathodes mimicking plant cell – An effective strategy to enhance photoelectrocatalytic carbon dioxide reduction and systematic mechanism investigation

Semiconductors, such as metal oxides and metal sulfides (MSX), are widely investigated as effectively catalytic materials to convert carbon dioxide (CO2) and water into chemicals under simulated solar light. These valuable investigations might address both the energy crisis and climate change in our modern society. Herein, a novel strategy to construct leaf-like heterojunctions of VS-ZnIn2S4/TiN-x is reported. The new semiconductor heterojunctions were then applied to photoelectrocatalytic CO2 reduction, achieving excellent performance (formate formation rate of 1173.2 μM h−1 cm−2) attributed to the plant cell-like morphology and enhanced electron mobility from the heterojunction interfaces to the active sites on the surface. Our findings suggest that titanium nitride (TiN) with good conductivity can improve the photoelectrocatalytic ability of MSX through heterojunction construction. The photocathode VS-ZnIn2S4/TiN-3 exhibits 81.0 % selectivity toward C2 products by optimizing the material structure and reaction conditions. According to the systematic investigation of operando Fourier transform infrared (FTIR) spectra, common intermediates such as *COO−, *COOH, *CO, *CHO, *COCHO, and *COCH3 reported in the literature were carefully verified. Among these, the carbene specie serve as the key intermediate responsible for generating other intermediates and resulting in all products.

Regulation mechanism of wavy β12 borophene-supported dual-atom catalysts on ethanol product

Improving CO2RR electrocatalysis is vital for meeting growing energy demands. Dual-atom catalysts (DACs) show promise, with activity tunable via stress-responsive substrates. Highly flexible borophene, exhibiting periodic undulations under stress, emerges as an attractive DAC substrate. Despite potential, wave-like DACs for C2 production remain unexplored due to modeling complexities and unknown intermediates. We present wave-like borophene anchored with Cu atoms, studied via density functional theory, revealing synergistic effects and surface restructuring mechanisms in C2 reactions. Stressing borophene reduces ethanol reduction overpotential (from 0.75 V to 0.60 V) and enhances interfacial interactions. This work highlights the potential of stress-modulated substrates in advancing efficient alcohol conversion strategies, paving the way for the innovative design and optimization of dual-atom catalysts (DACs).

Amorphous Strategy and Doping Copper on Metal-Organic Framework Surface for Enhanced Photocatalytic CO2 Reduction to C2H4.

Amorphous photocatalysts are characterized by numerous grain boundaries and abundant unsaturated sites, which enhance reaction efficiency from both kinetic and thermodynamic perspectives. However, amorphization strategies have rarely been used for photocatalytic CO2 reduction. Doping copper onto a metal-organic framework (MOF) surface can regulate the electronic structure of photocatalysts, promote electron transfer from the MOF to Cu, and improve the separation efficiency of electron-hole pairs. In this study, an amorphous photocatalyst MOFw-p/Cu containing highly dispersed Cu (0, I, II) sites was designed and synthesized by introducing a regulator and in situ copper species during the nucleation process of MOF (UiO-66-NH2). Various characterizations confirmed that the Cu species were anchored to the organometallic skeleton of the surface amorphization MOF structure. The synergistic effect of Cu doping and surface amorphization in MOFw-p/Cu can significantly enhance the CO and CH4 yields while promoting the formation of the multicarbon product C2H4. The approach holds promise for developing novel, highly efficient MOFs as photocatalysts for CO2 photoreduction, enabling the production of high-value-added C2 products.

Supported Au single atoms and nanoparticles on MoS2 for highly selective CO2-to-CH3COOH photoreduction

Effectively controlling the selective conversion of CO2 photoreduction to C2 products presents a significant challenge. Here, we develop a heterojunction photocatalyst by controllably implanting Au nanoparticles and single atoms into unsaturated Mo atoms of edge-rich MoS2, denoted as Aun/Au1-CMS. Photoreduction of CO2 results in the production of CH3COOH with a selectivity of 86.4%, which represents a 6.4-fold increase compared to samples lacking single atoms, and the overall selectivity for C2 products is 95.1%. Furthermore, the yield of CH3COOH is 22.4 times higher compared to samples containing single atoms and without nanoparticles. Optical experiments demonstrate that the single atoms domains can effectively capture photoexcited electrons by the Au nanoparticles, or the local electric field generated by the nanoparticles promotes the transfer of photogenerated electrons in MoS2 to Au single atoms, prolonging the relaxation time of photogenerated electrons. Mechanistic investigations reveal that the orbital coupling of Au5d and Mo4d strengthens the oxygen affinity of Mo and carbon affinity of Au. The hybridized orbitals reduce energy splitting levels of CO molecular orbitals, aiding C–C coupling. Moreover, the Mo−Au dual-site stabilize the crucial oxygen-associated intermediate *CH2CO, thereby enhancing the selectivity towards CH3COOH. The cross-scale heterojunctions provide an effective strategy to simultaneously address the kinetical and thermodynamical limitations of CO2-to-CH3COOH conversion.

Unconventional Electrocatalytic CO Conversion to C2 Products on Single‐Atomic Pd−Agn Sites

AbstractThe electrochemical reduction of CO or CO2 into C2+ products has mostly been focused on Cu‐based catalysts. Although Ag has also been predicted as a possible catalyst for the CO‐to‐C2+ conversion from the thermodynamic point of view, however, due to its weak CO binding strength, CO rapidly desorbs from the Ag surface rather than participates in deep reduction. In this work, we demonstrate that single‐atomic Pd sites doped in Ag lattice can tune the CO adsorption behavior and promote the deep reduction of CO toward C2 products. The monodispersed Pd−Agn sites enable the CO adsorption with both Pd‐atop (PdL) and Pd−Ag bridge (PdAgB) configurations, which can increase the CO coverage and reduce the C−C coupling energy barrier. Under room temperature and ambient pressure, the Pd1Ag10 alloy catalyst exhibited a total CO‐to‐C2 Faradaic efficiency of ~37 % at −0.83 V, with appreciable current densities and electrochemical stability, thus featuring unconventional non‐Cu electrocatalytic CO‐to‐C2 conversion capability.

Photochemical conversion of CO to C1 and C2 products mediated by porphyrin rhodium(II) metallo-radical complexes

Unimolecular reduction and bimolecular reductive coupling of carbon monoxide (CO) represent important ways to synthesize organic feedstocks. Reductive activation of CO through open-shell pathways, though rare, can help overcome the barriers of many traditional organometallic elementary reactions that are hard to achieve. Herein we successfully achieve the unimolecular reduction of CO to (TPP)RhCH2OSiR1R2R3 (TPP = 5,10,15,20-tetraphenylporphyrin), and the release of products CH3OSiR1R2R3, TEMPO-CH2OSiR1R2R3 and BrCH2OSiR1R2R3 in near-quantitative yield under visible light (420–780 nm), which involves radical formation from Rh-C bond homolysis. Bimolecular CO reductive coupling products, (TPP)RhCOCH2OSiR1R2R3, are then obtained via a radical mechanism. Subsequent treatment with n-propylamine, BrCCl3 or TEMPO under thermal or photochemical conditions afford small-molecule bimolecular reductive coupling products. To the best of our knowledge, homogeneous systems which reductively couple CO under photochemical conditions have not been reported before. Here, the use of an open-shell transition metal complex, that delivers more than one kind of small-molecule CO reductive coupling products bearing different functional groups, provides opportunities for useful CO reductive transformations.

Revolutionizing CO2‐to‐C2 Conversion: Unleashing the Potential of CeO2 Nanocores for Self‐ Supported Electrocatalysts with Cu2O Nanoflakes on 3D Graphene Aerogel

AbstractCu serves as a promising electrocatalyst for converting CO2 into valuable C2 products in CO2 reduction reactions (CO2RR). However, instability in CO* formation is crucial for CO2 adsorption‐ desorption still remains a challenge under reduction conditions. This study explores the impact of lanthanide oxide, particularly CeO2, on Cu‐based catalytic performances. By leveraging Ce's distinctive electronic structure, CO* species are stabilized during the reaction in CeO2─Cu2O, resulting in exceptional catalytic performance for CO2 electroreduction to C2 products. Hybridizing CeO2‐Cu2O with graphene aerogel enhances electrochemical active surface area and CO2RR efficiency. The resulting CeO2─Cu2O(10%)/GA electrocatalyst exhibits a remarkable faradaic efficiency for C2 products, exceeding 62%, alongside exceptional stability over 80 h with wide potential window (−0.8 to −1.2 V) using a H‐cell. Systematic investigations elucidate the intricate interplay between surface properties and catalytic activity. Furthermore, a solar cell‐ powered CO2 reduction system demonstrates consistent performance (−27.8 mA cm−2 at 3.46 V) under solar radiation of ≈100 mW cm−2, showcasing outstanding stability with nearly 100% retention over 4 h of continuous illumination. In short, by harnessing catalytic and electronic effects, this innovation advances the development of electrocatalysts with heightened CO2‐to‐C2 selectivity, bridging fundamental research with technological innovation to tackle critical global challenges.

Interstitial Boron Atoms in Pd Aerogel Selectively Switch the Pathway for Glycolic Acid Synthesis from Waste Plastics.

Electro-reforming of poly(ethylene terephthalate) (PET) into valuable chemicals is garnering significant attention as it opens a mild avenue for waste resource utilization. However, achieving high activity and selectivity for valuable C2 products during ethylene glycol (EG) oxidation in PET hydrolysate on Pd electrocatalysts remains challenging. The strong interaction between Pd and carbonyl (*CO) intermediates leads to undesirable over-oxidation and poisoning of Pd sites, which hinders the highly efficient C2 products production. Herein, a nonmetallic alloying strategy is employed to fabricate a Pd-boron alloy aerogel (PdB), wherein B atoms are induced to regulate the electron structure and surface oxophilicity. This approach allows a remarkable mass activity of 6.71 A mgPd -1, glycolic acid (GA) Faradaic efficiency (FE) of 93.8%, and stable 100 h cyclic electrolysis. In situ experiments and density functional theory calculations reveal the contributions of B inserted in Pd lattice on highly effective EG-to-GA conversion. Interestingly, the heightened surface oxophilicity and regulated electronic structure by B incorporation weakened *CO intermediates adsorption and enhanced hydroxyl species affinity to accelerate oxidative *OH adspecies formation, thereby synergistically avoiding over-oxidation and boosting GA synthesis. This work provides valuable insights for the rational design of high-performance electrocatalysts for GA synthesis via an oxophilic B motifs incorporation strategy.

Core-shell structured Cu2O@NiAl-LDH/CQDs photocatalysts for efficient photocatalytic reduction of CO2 to C2 products

Photocatalytic CO2 reduction to high-value C2 fuels is considered a promising technology, but still challenging due to the complex multi-electronic steps and CC coupling involved. In this paper, a Cu2O@NiAl-LDH/CQDs composite with a core–shell structure is designed for the highly selective photoreduction of CO2 to C2H6. A series of characterizations show that the construction of Cu2O@NiAl-LDH heterojunctions accelerates the transfer of photogenerated electrons from NiAl-LDH to Cu2O which improves the yield and selectivity of C2H6. The C2H6 yield of the best sample, Cu2O@NiAl-LDH/CQDs-10, is as high as 8.18 μmol g-1 h−1, and the electron selectivity is 69.85 %, which is 15.7 times higher than Cu2O. In-situ DRIFTS showed that the Cu2O@NiAl-LDH/CQDs composites were able to promote the adsorption of CO* and the generation of COCO*, and facilitate the CC coupling to generate C2H6.

Hyperpolarized 13C NMR Reveals Pathway Regulation in Lactococcus lactis and Metabolic Similarities and Differences Across the Tree of Life.

The control of metabolic networks is incompletely understood, even for glycolysis in highly studied model organisms. Direct real-time observations of metabolic pathways can be achieved in cellular systems with 13C NMR using dissolution Dynamic Nuclear Polarization (dDNP NMR). The method relies on a short-lived boost of NMR sensitivity using a redistribution of nuclear spin states to increase the alignment of the magnetic moments by more than four orders of magnitude. This temporary boost in sensitivity allows detection of metabolism with sub-second time resolution. Here, we hypothesized that dDNP NMR would be able to investigate molecular phenotypes that are not easily accessible with more conventional methods. The use of dDNP NMR allows real-time insight into carbohydrate metabolism in a Gram-positive bacterium (Lactoccocus lactis), and comparison to other bacterial, yeast and mammalian cells shows differences in the kinetic barriers of glycolysis across the kingdoms of life. Nevertheless, the accumulation of non-toxic precursors for biomass at kinetic barriers is found to be shared across the kingdoms of life. We further find that the visualization of glycolysis using dDNP NMR reveals kinetic characteristics in transgenic strains that are not evident when monitoring the overall glycolytic rate only. Finally, dDNP NMR reveals that resting Lactococcus lactis cells use the influx of carbohydrate substrate to produce acetoin rather than lactate during the start of glycolysis. This metabolic regime can be emulated using suitably designed substrate mixtures to enhance the formation of the C4 product acetoin more than 400-fold. Overall, we find that dDNP NMR provides analytical capabilities that may help to clarify the intertwined mechanistic determinants of metabolism and the optimal usage of biotechnologically important bacteria.