Homogeneity of Supported Single‐Atom Active Sites Boosting the Selective Catalytic Transformations

Abstract

Selective conversion of specific functional groups to desired products is highly important but still challenging in industrial catalytic processes. The adsorption state of surface species is the key factor in modulating the conversion of functional groups, which is correspondingly determined by the uniformity of active sites. However, the non‐identical number of metal atoms, geometric shape, and morphology of conventional nanometer‐sized metal particles/clusters normally lead to the non‐uniform active sites with diverse geometric configurations and local coordination environments, which causes the distinct adsorption states of surface species. Hence, it is highly desired to modulate the homogeneity of the active sites so that the catalytic transformations can be better confined to the desired direction. In this review, the construction strategies and characterization techniques of the uniform active sites that are atomically dispersed on various supports are examined. In particular, their unique behavior in boosting the catalytic performance in various chemical transformations is discussed, including selective hydrogenation, selective oxidation, Suzuki coupling, and other catalytic reactions. In addition, the dynamic evolution of the active sites under reaction conditions and the industrial utilization of the single‐atom catalysts are highlighted. Finally, the current challenges and frontiers are identified, and the perspectives on this flourishing field is provided.

Noble Metal-Free 2D 1T-MoS2 Edge Sites Boosting Selective Hydrogenation of Maleic Anhydride

“…Furthermore, it is observed from the DFT simulation results that the DOS of the synthesized 1T-MoS 2 around the Fermi level is continuous, while 2H-MoS 2 shows a significant gap near the Fermi level from the results of DOS as shown in Figures d and S17 (projected DOS). These results further confirm that 2D MoS 2 has a better capacity for H 2 activation, , which is consistent with the experimental results. These significant changes on the d-band center and DOS reveal that the electron-rich Mo sites in 1T-MoS 2 intrinsically behave with much better capability for H 2 activation, which corroborates the H 2 -DRIFTS and H 2 -TPR results.…”

Pd/δ-MnO2 nanoflower arrays cordierite monolithic catalyst toward toluene and o-xylene combustion

“…The FESEM results verify that the δ-MnO 2 nanoflower arrays can serve as the ideal support to anchor the Pd NPs and efficiently prevent their further aggregation during the synthetic process of electroless plating. Therefore, the size of deposited Pd NPs can be well adjusted by virtue of the steric hindrance effect by the δ-MnO 2 nanoflowers ( Zheng et al, 2021 ; Shi et al, 2022 ).…”

Superior Pd–Rh Three-Way Catalyst: Modulating the Surface Composition by Introducing Ceria-Zirconia with Partial κ-Ce2Zr2O8 Structure as Support

“…CO FTIR, CO chemisorption, and XPS are performed to evaluate the dispersion, oxidation state, and relative amount of Pd species in Pd-only catalysts . Generally, the position of the CO adsorption band on the metal Pd (Pd 0 ) relies on the configuration of metal sites and particle size. , It can be seen in Figure a that three bands are presented in the CO FTIR spectra. The band (HF) located at 2053–2076 cm –1 is assigned to the CO chemisorbed on Pd 0 at the steps and edges position in linear form ( n CO / n Pd = 1:1), implying the existence of relatively small Pd particles.…”