Carbon nitride supported Fe2 cluster catalysts with superior performance for alkene epoxidation

Abstract

Sub-nano metal clusters often exhibit unique and unexpected properties, which make them particularly attractive as catalysts. Herein, we report a “precursor-preselected” wet-chemistry strategy to synthesize highly dispersed Fe2 clusters that are supported on mesoporous carbon nitride (mpg-C3N4). The obtained Fe2/mpg-C3N4 sample exhibits superior catalytic performance for the epoxidation of trans-stilbene to trans-stilbene oxide, showing outstanding selectivity of 93% at high conversion of 91%. Molecular oxygen is the only oxidant and no aldehyde is used as co-reagent. Under the same condition, by contrast, iron porphyrin, single-atom Fe, and small Fe nanoparticles (ca. 3 nm) are nearly reactively inert. First-principles calculations reveal that the unique reactivity of the Fe2 clusters originates from the formation of active oxygen species. The general applicability of the synthesis approach is further demonstrated by producing other diatomic clusters like Pd2 and Ir2, which lays the foundation for discovering diatomic cluster catalysts.

Targeted Synergy between Adjacent Co Atoms on Graphene Oxide as an Efficient New Electrocatalyst for Li–CO2 Batteries

“…The distance between adjacent bright Co dots ranges from ≈1.20 to 2.54, Å, based on statistical analysis of 100 adjacent Co samples (Figure e; Figure S5, Supporting Information). The mean Co–Co distance is ≈1.79 Å, suggesting that some form Co dimers . To further investigate morphology of the adjacent Co we carefully reviewed a significant number of STEM images for proportions of SA Co, adjacent Co, and patch Co (Figure f).…”

Intrinsic Effect of Carbon Supports on the Activity and Stability of Precious Metal Based Catalysts for Electrocatalytic Alcohol Oxidation in Fuel Cells: A Review

“…Dual‐site catalysts in which the two metal centers are connected by nitrogen or other nonmetal atoms (Figure C and D) are excluded from the current discussion . The two active centers can be the same or different elements . To increase the stability of BACs, they are generally embedded in the carbon substrate and coordinated with C or N atoms .…”

“…BACs show much higher activity and selectivity for electrochemical reactions than single‐atom catalysts . DFT calculations showed that Pt–Fe BAC embedded in graphene significantly enhances the CO tolerance of Pt catalyst in direct methanol fuel cells (DMFCs) .…”

Selective C−C Coupling by Spatially Confined Dimeric Metal Centers

“…Several candidate systems including Sc2, Ti2, Cr2, Mn2 and Fe2 dimers on the 6N-V6 monolayer have adsorption energies of −3.71 ~ −0.48 eV for fixation of two CO2 molecules (Figure 3 and Figure S3), while the other metal dimers are only able to bind one CO2 molecule. Considering that Fe is an earthabundant element and dispersed Fe atoms and dimers can be readily obtained in the experiment (Ye et al, 2019;Tian et al, 2018), thereafter we explored Fe2 dimer on various nitrogenated 2D holey carbon materials as a representative of dual metal centers. and 4N-V2, 5N-V3, and 6N-V4(a) increases with both N content and hole size.…”