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Photothermal CO2 methanation reaction represents a promising strategy for addressing CO2‐related environmental issues. The presence of efficient tandem catalytic sites with a localized high‐temperature is an effective pathway to enhance the performance of CO2 methanation. Here the bimetallic RuCo nanoparticles anchored on ZrO2 fiber cotton (RuCo/ZrO2) as a photothermal catalyst for CO2 methanation are prepared. A significant photothermal CO2 methanation performance with optimal CH4 selectivity (99%) and rate (169.93 mmol gcat−1 h−1) is achieved. The photothermal energy of the RuCo bimetallic nanoparticles, confined by the infrared insulation and low thermal conductivity of the ZrO2 fiber cotton (ZrO2 FC), provides a localized high‐temperature. In situ spectroscopic experiments on RuCo/ZrO2, Ru/ZrO2, and Co/ZrO2 indicate that the construction of tandem catalytic sites, where the Co site favors CO2 conversion to CO while incorporating Ru enhances CO* adsorption for subsequent hydrogenation, results in a higher selectivity toward CH4. This work opens a new insight into designing tandem catalysts with a photothermal confinement effect in CO2 methanation reaction. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET) and CO2, two chemical wastes that urgently need to be transformed in the environment, are converted simultaneously in a one‐pot catalytic process through the synergistic coupling of three reactions: CO2 hydrogenation, PET methanolysis and dimethyl terephthalate (DMT) hydrogenation. More interestingly, the chemical equilibria of both reactions were shifted forward due to a revealed dual‐promotion effect, leading to significantly enhanced PET depolymerization. The overall methanol yield from CO2 hydrogenation exceeded the original thermodynamic equilibrium limit since the methanol was in situ consumed in the PET methanolysis. The degradation of PET by a stoichiometric ratio of methanol was significantly enhanced because the primary product, DMT was hydrogenated to dimethyl cyclohexanedicarboxylate (DMCD) or p‐xylene (PX). This synergistic catalytic process provides an effective way to simultaneously recycle two wastes, polyesters and CO2, for producing high‐value chemicals. [ABSTRACT FROM AUTHOR]

Deuterium (D) labeling is of great value in organic synthesis, pharmaceutical industry, and materials science. However, the state‐of‐the‐art deuteration methods generally require noble metal catalysts, expensive deuterium sources, or harsh reaction conditions. Herein, noble metal‐free and ultrathin ZnIn2S4 (ZIS) is reported as an effective photocatalyst for visible light‐driven reductive deuteration of carbonyls to produce deuterated alcohols using heavy water (D2O) as the sole deuterium source. Defective two‐dimensional ZIS nanosheets (D‐ZIS) are prepared in a surfactant assisted bottom‐up route exhibited much enhanced performance than the pristine ZIS counterpart. A systematic study is carried out to elucidate the contributing factors and it is found that the in situ surfactant modification enabled D‐ZIS to expose more defect sites for charge carrier separation and active D‐species generation, as well as high specific surface area, all of which are beneficial for the desirable deuteration reaction. This work highlights the great potential in developing low‐cost semiconductor‐based photocatalysts for organic deuteration in D2O, circumventing expensive deuterium reagents and harsh conditions. [ABSTRACT FROM AUTHOR]

Efficient synthesis of higher alcohols from syngas over a single‐metal catalyst remains challenging because both active sites for CO dissociation and molecular CO adsorption are required. We report herein that iron nitrides can directly catalyze syngas to higher alcohols with high selectivity. Three iron nitride catalysts (Fe2N, Fe3N, and Fe4N) were fabricated via the nitriding of α‐Fe and their structures were confirmed by X‐ray diffraction (XRD) and Mössbauer spectroscopy (MES). Moreover, no carbides were detected even after syngas conversion for Fe2N and Fe3N catalysts, in which the N content was higher than that in Fe4N (iron nitrides transformed to Fe2C partly). The catalytic performance indicated that higher alcohols could be directly produced from syngas with remarkable selectivity (>51 % for C2+OH selectivity in total alcohols) over iron nitrides, which was tentatively ascribed to the unique electronic structure of iron nitrides, as evidenced by DFT calculation. This study proposed a novel method for the selective one‐step synthesis of higher alcohols from syngas. [ABSTRACT FROM AUTHOR]

As a prerequisite elementary step, carburization of iron oxides to form iron carbides is critically important to display activity for iron‐based Fischer–Tropsch synthesis catalysts. The positive role of the Cu promoter to advocate the reduction of the iron oxides has long been known. Nevertheless, its complex influence along the carburization of catalyst precursors remains controversial. Here, we resolve this decades‐long question by using a state‐of‐the‐art in situ X‐ray diffraction (XRD) method to elucidate the multi‐role of Cu promoter in modulation of carburization rate, composition of post‐carburization samples, and morphology evolution of prepared iron carbide particles under CO/He (v/v=2 %/98 %) and H2/CO/He (v/v/v=8 %/2 %/90 %) gaseous environment, by excluding the possible interference from promoter components other than Cu. We anticipate that this study enriches current tool box in the research of a specific promoter of the Fischer‐Tropsch synthesis catalysts. In situ seeing is believing: The complex influence of Cu promoter along the carburization of iron catalyst precursors has been elucidated by using a state‐of‐the‐art in situ X‐ray diffraction (XRD) method. Particularly, the multi‐role of Cu promoter in modulation of carburization rate, composition of post‐carburization samples, and morphology evolution of prepared iron carbide particles under CO/He (v/v=2 %/98 %) and H2/CO/He (v/v/v=8 %/2 %/90 %) gaseous environment, by excluding the possible interference from promoter components other than Cu. [ABSTRACT FROM AUTHOR]

Abstract: Capped chelating organic molecules are presented as a design principle for tuning heterogeneous nanoparticles for electrochemical catalysis. Gold nanoparticles (AuNPs) functionalized with a chelating tetradentate porphyrin ligand show a 110‐fold enhancement compared to the oleylamine‐coated AuNP in current density for electrochemical reduction of CO2 to CO in water at an overpotential of 340 mV with Faradaic efficiencies (FEs) of 93 %. These catalysts also show excellent stability without deactivation (<5 % productivity loss) within 72 hours of electrolysis. DFT calculation results further confirm the chelation effect in stabilizing molecule/NP interface and tailoring catalytic activity. This general approach is thus anticipated to be complementary to current NP catalyst design approaches. [ABSTRACT FROM AUTHOR]

Reported here is the chelate effect as a design principle for tuning heterogeneous catalysts for electrochemical CO2 reduction. Palladium functionalized with a chelating tris‐N‐heterocyclic carbene (NHC) ligand (Pd‐timtmbMe) exhibits a 32‐fold increase in activity for electrochemical reduction of CO2 to C1 products with high Faradaic efficiency (FEC1=86 %) compared to the parent unfunctionalized Pd foil (FE=23 %), and with sustained activity relative to a monodentate NHC‐ligated Pd electrode (Pd‐mimtmbMe). The results highlight the contributions of the chelate effect for tailoring and maintaining reactivity at molecular‐materials interfaces enabled by surface organometallic chemistry. [ABSTRACT FROM AUTHOR]

A study of the promotional effect of potassium on the carburization behavior of a series of spray-dried precipitated Fe2O3 catalysts (100 Fe, 100 Fe/0.52 K, 100 Fe/1.54 K, and 100 Fe/2.4 K) has been performed by using in situ XRD. The average crystallite size evolution for species such as α-Fe2O3, Fe3O4, χ-Fe5C2, and θ-Fe3C were followed. The potassium promoter clearly inhibits the reduction of α-Fe2O3 to Fe3O4, where the decreasing binding energy in the Fe 2p3/2, O 1s and K 2p3/2 spectra from X-ray photoelectron spectroscopy (XPS) suggests an electron density increase in Fe and O upon potassium promotion, leading to the enhanced covalency in the Fe−O bond. In terms of crystallite size during carburization, an optimum potassium loading exists in catalyst 100 Fe/0.52 K, which shows the fastest reduction to Fe3O4 with minimum crystallite sizes of around 7 to 15 nm. Potassium has no clear effect in determining the final crystallite size of χ-Fe5C2. An arch-shaped curve in the evolution of crystallite size of the Fe3O4 intermediate was observed, which can be explained by the activation energy difference between the bidirectional steps of the outward oxygen diffusion and the inward carbon diffusion. [ABSTRACT FROM AUTHOR]