Regulating Surface‐Interface Structures of Zn‐Incorporated LiAl‐LDH Supported Ru Catalysts for Efficient Benzene Hydrogenation to Produce Cyclohexene

Abstract

In the heterogeneous catalysis, adsorption and desorption behaviors of reactants and products on the surface of catalysts can remarkably impact their catalytic activities and product selectivities. Here, series of Ru-based catalysts supported on Znincorporated LiÀ Al layered double hydroxides (Ru/LDH) were developed and employed in the selective benzene hydrogenation to produce cyclohexene without the use of any additional zinc salt additives. It was demonstrated that asconstructed supported Ru catalyst bearing a Zn/(Li + Zn) molar ratio of 0.075 in the LDH support gave a higher cyclohexene yield of 43.2 % than those over other Ru-based ones. Combining structural characterizations and catalytic hydrogenation reac-tions with temperature-programmed desorption and in situ Fourier transform infrared spectroscopy of benzene and cyclohexene, it was revealed that the generation of appropriate surficial/interfacial Ru 0 /Ru δ + À OÀ Zn structures, as well as the existence of abundant hydroxyl groups on LDH supports, could facilitate the benzene adsorption and the cyclohexene desorption, thereby remarkably promoting the formation of cyclohexene. The present findings not only give a profound insight into the roles of surface-interface structures of supported Ru catalysts for efficient benzene hydrogenation to produce cyclohexene but also simultaneously provide a promising guide to design high-performance Ru-based catalysts.

A-site defective La2−xCuO4 perovskite-type oxides for efficient oxidation of cyclohexylbenzene

“…It is inferred that surface Cu + sites as Lewis acid sites may be conducive to the adsorption of CHB through the benzene ring π-bonding effect. 40,41 The coexistence of CuO and La 2 CuO 4 can be further proven by EPR spectra. As presented in Fig.…”

“…ring π-bonding effect. 40,41 The coexistence of CuO and La 2 CuO 4 can be further proven by EPR spectra. As presented in Fig.…”

Ru-Loaded Biphasic TiO2 Nanosheet-Tubes Enriched with Ti3+ Defects and Directionally Deficient Electrons as Highly Efficient Catalysts in Benzene Selective Hydrogenation

“…Titanium mainly exists in the Ti 4+ state, while the detection of a Ti 3+ state aligns with the observations reported in EPR studies. Figure 4D exhibits the O 1s XPS spectra of the catalysts, and peaks near 530.0, 531.8, and 533.5 eV are attributed to lattice oxygen (O L ), oxygen vacancies (O V ), and adsorbed water (H 2 O) [24,38,42]. In conclusion, both EPR and XPS indicate the presence of a small amount of electron-deficient Ru δ+ , as well as Ti 3+ and O V on the Ru/TNSTs-t catalyst.…”

“…To date, a number of methods for engineering titanium dioxide to improve cyclohexene selectivity in benzene hydrogenation reactions have been developed, which provide valuable insights into how to optimize the performance of catalysts by tuning the properties of TiO 2 , such as surface species tuning [23,24], polycrystalline structure manipulation [25,26], crystalline surface control [8,27], morphology manipulation [21], etc. Among these, the design of titanium dioxide morphology and the modulation of crystal properties are deemed the most practical and effective approaches to enhancing catalyst performance.…”