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 MoS greatly enhanced the CO 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 CO into methanol without the formation of formic acid, whereas CO 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.
Exploring how hydrophilicity regulates catalytic properties at the molecular level remains a grand challenge, although it has great potential to offer guidelines for developing highly efficient catalysts and deepen the mechanistic understanding of heterogeneous catalysis. Here, we provide molecular-level insight into the influence of surface hydroxyl groups on hydrophilic SiC quantum dots (QDs) on CO 2 hydrogenation. In CO 2 hydrogenation into methanol, SiC QDs exhibited higher catalytic activity and lower activation energy than commercial SiC. Mechanistic studies revealed that the surface hydroxyl species on SiC QDs was directly involved in CO 2 hydrogenation through the addition of H atoms in hydroxyl groups into CO 2 to form HCOO* as the intermediate. The unique reaction path decreased the energy barrier for the formation of HCOO*, facilitating the activation of CO 2 . Our understanding of surface hydrophilicity directly instructs the development of efficient catalysts toward CO 2 hydrogenation.
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.
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.
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.
CO2 Methanation In their Research Article on page 14434, J. Bao, J. Zeng et al. report PdFe intermetallic nanocrystals with high activity and stability in CO2 methanation.
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%.
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