Achieving Efficient CO2 Electrolysis to CO by Local Coordination Manipulation of Nickel Single-Atom Catalysts.

Selective electroreduction of CO2 to C1 feed gas provides an attractive avenue to store intermittent renewable energy. However, most of the CO2-to-CO catalysts are designed from the perspective of structural reconstruction, and it is challenging to precisely design a meaningful confining microenvironment for active sites on the support. Herein, we report a local sulfur doping method to precisely tune the electronic structure of an isolated asymmetric nickel-nitrogen-sulfur motif (Ni1-NSC). Our Ni1-NSC catalyst presents >99% faradaic efficiency for CO2-to-CO under a high current density of -320 mA cm-2. In situ attenuated total reflection surface-enhanced infrared absorption spectroscopy and differential electrochemical mass spectrometry indicated that the asymmetric sites show a significantly weaker binding strength of *CO and a lower kinetic overpotential for CO2-to-CO. Further theoretical analysis revealed that the enhanced CO2 reduction reaction performance of Ni1-NSC was mainly due to the effectively decreased intermediate activation energy.

Surface Iron Species in Palladium-Iron Intermetallic Nanocrystals that Promote and Stabilize CO2 Methanation.

It is of pivotal importance to develop efficient catalysts and investigate the intrinsic mechanism for CO2 methanation. Now, it is reported that PdFe intermetallic nanocrystals afforded high activity and stability for CO2 methanation. The mass activity of fct-PdFe nanocrystals reached 5.3 mmol g-1 h-1 , under 1 bar (CO2 :H2 =1:4) at 180 °C, being 6.6, 1.6, 3.3, and 5.3 times as high as that of fcc-PdFe nanocrystals, Ru/C, Ni/C, and Pd/C, respectively. After 20 rounds of successive reaction, 98 % of the original activity was retained for PdFe intermetallic nanocrystals. Further mechanistic studies revealed that PdFe intermetallic nanocrystals enabled the maintenance of metallic Fe species via a reversible oxidation-reduction process in CO2 methanation. The metallic Fe in PdFe intermetallic nanocrystals induced the direct conversion of CO2 into CO* as the intermediate, contributing to the enhanced activity.

Hepatocyte Growth Factor DNA Aptamer for Prevention of Postoperative Peritoneal Adhesion via Enhancement of Fibrinolysis and Inhibition of Mesothelial Mesenchymal Transition.

Postoperative peritoneal adhesion (PPA) is a prevalent complication of abdominal surgery, posing a significant hindrance to postsurgical recovery. Although several strategies have been developed to alleviate and prevent adhesions, their efficacy remains unsatisfactory. For the first time, we studied the therapeutic effect and mechanism of our recently developed thermally stable oligonucleotide-based mimetics of hepatocyte growth factor (HGF DNA aptamer) to prevent PPA. The HGF DNA aptamer effectively inhibited canonical TGF-ß1 signaling transduction, partially suppressing mesothelial mesenchymal transition. Additionally, the aptamer, respectively, upregulated and downregulated the expression of tissue plasminogen activator and plasminogen activator inhibitor 1, thereby enhancing fibrinolytic activity. As a pleiotropic factor, the HGF DNA aptamer also enhanced the migratory and proliferative capacities of mesothelial cells. Finally, the aptamer demonstrated a higher level of effectiveness in preventing PPAs than the commercially available antiperitoneal adhesion barrier, Seprafilm. Due to its therapeutic benefits, excellent stability, biosafety, cost-effectiveness, and versatility, the HGF DNA aptamer demonstrates promise for preventing PPA in future clinical settings.

Turning copper into an efficient and stable CO evolution catalyst beyond noble metals.

Using renewable electricity to convert CO2 into CO offers a sustainable route to produce a versatile intermediate to synthesize various chemicals and fuels. For economic CO2-to-CO conversion at scale, however, there exists a trade-off between selectivity and activity, necessitating the delicate design of efficient catalysts to hit the sweet spot. We demonstrate here that copper co-alloyed with isolated antimony and palladium atoms can efficiently activate and convert CO2 molecules into CO. This trimetallic single-atom alloy catalyst (Cu92Sb5Pd3) achieves an outstanding CO selectivity of 100% (±1.5%) at -402 mA cm-2 and a high activity up to -1 A cm-2 in a neutral electrolyte, surpassing numerous state-of-the-art noble metal catalysts. Moreover, it exhibits long-term stability over 528 h at -100 mA cm-2 with an FECO above 95%. Operando spectroscopy and theoretical simulation provide explicit evidence for the charge redistribution between Sb/Pd additions and Cu base, demonstrating that Sb and Pd single atoms synergistically shift the electronic structure of Cu for CO production and suppress hydrogen evolution. Additionally, the collaborative interactions enhance the overall stability of the catalyst. These results showcase that Sb/Pd-doped Cu can steadily carry out efficient CO2 electrolysis under mild conditions, challenging the monopoly of noble metals in large-scale CO2-to-CO conversion.

Direct synthesis of extra-heavy olefins from carbon monoxide and water.

Extra-heavy olefins (C12+=), feedstocks to synthesize a wide range of value-added products, are conventionally generated from fossil resources via energy-intensive wax cracking or multi-step processes. Fischer-Tropsch synthesis with sustainably obtained syngas as feed-in provides a potential way to produce C12+=, though there is a trade-off between enhancing C-C coupling and suppressing further hydrogenation of olefins. Herein, we achieve selective production of C12+= via the overall conversion of CO and water, denoted as Kölbel-Engelhardt synthesis (KES), in polyethylene glycol (PEG) over a mixture of Pt/Mo2N and Ru particles. KES provides a continuously high CO/H2 ratio, thermodynamically favoring chain propagation and olefin formation. PEG serves as a selective extraction agent to hinder hydrogenation of olefins. Under an optimal condition, the yield ratio of CO2 to hydrocarbons reaches the theoretical minimum, and the C12+= yield reaches its maximum of 1.79 mmol with a selectivity (among hydrocarbons) of as high as 40.4%.

Selective CO2 electrolysis to CO using isolated antimony alloyed copper.

Renewable electricity-powered CO evolution from CO2 emissions is a promising first step in the sustainable production of commodity chemicals, but performing electrochemical CO2 reduction economically at scale is challenging since only noble metals, for example, gold and silver, have shown high performance for CO2-to-CO. Cu is a potential catalyst to achieve CO2 reduction to CO at the industrial scale, but the C-C coupling process on Cu significantly depletes CO* intermediates, thus limiting the CO evolution rate and producing many hydrocarbon and oxygenate mixtures. Herein, we tune the CO selectivity of Cu by alloying a second metal Sb into Cu, and report an antimony-copper single-atom alloy catalyst (Sb1Cu) of isolated Sb-Cu interfaces that catalyzes the efficient conversion of CO2-to-CO with a Faradaic efficiency over 95%. The partial current density reaches 452 mA cm-2 with approximately 91% CO Faradaic efficiency, and negligible C2+ products are observed. In situ spectroscopic measurements and theoretical simulations reason that the atomic Sb-Cu interface in Cu promotes CO2 adsorption/activation and weakens the binding strength of CO*, which ends up with enhanced CO selectivity and production rates.

Manipulating local coordination of copper single atom catalyst enables efficient CO2-to-CH4 conversion.

Electrochemical CO2 conversion to methane, powered by intermittent renewable electricity, provides an entrancing opportunity to both store renewable electric energy and utilize emitted CO2. Copper-based single atom catalysts are promising candidates to restrain C-C coupling, suggesting feasibility in further protonation of CO* to CHO* for methane production. In theoretical studies herein, we find that introducing boron atoms into the first coordination layer of Cu-N4 motif facilitates the binding of CO* and CHO* intermediates, which favors the generation of methane. Accordingly, we employ a co-doping strategy to fabricate B-doped Cu-Nx atomic configuration (Cu-NxBy), where Cu-N2B2 is resolved to be the dominant site. Compared with Cu-N4 motifs, as-synthesized B-doped Cu-Nx structure exhibits a superior performance towards methane production, showing a peak methane Faradaic efficiency of 73% at -1.46 V vs. RHE and a maximum methane partial current density of -462 mA cm-2 at -1.94 V vs. RHE. Extensional calculations utilizing two-dimensional reaction phase diagram analysis together with barrier calculation help to gain more insights into the reaction mechanism of Cu-N2B2 coordination structure.

Synergetic interaction between neighbouring platinum monomers in CO2 hydrogenation.

Exploring the interaction between two neighbouring monomers has great potential to significantly raise the performance and deepen the mechanistic understanding of heterogeneous catalysis. Herein, we demonstrate that the synergetic interaction between neighbouring Pt monomers on MoS2 greatly enhanced the CO2 hydrogenation catalytic activity and reduced the activation energy relative to isolated monomers. Neighbouring Pt monomers were achieved by increasing the Pt mass loading up to 7.5% while maintaining the atomic dispersion of Pt. Mechanistic studies reveal that neighbouring Pt monomers not only worked in synergy to vary the reaction barrier, but also underwent distinct reaction paths compared with isolated monomers. Isolated Pt monomers favour the conversion of CO2 into methanol without the formation of formic acid, whereas CO2 is hydrogenated stepwise into formic acid and methanol for neighbouring Pt monomers. The discovery of the synergetic interaction between neighbouring monomers may create a new path for manipulating catalytic properties.