Advances in morphology-controlled alumina and its supported Pd catalysts: synthesis and applications

Alumina materials, as one of the cornerstones of the modern chemical industry, possess physical and chemical properties that include excellent mechanical strength and structure stability, which also make them highly suitable as catalyst supports. Alumina-supported Pd-based catalysts with the advantages of exceptional catalytic performance, flexible regulated surface metal/acid sites, and good regeneration ability have been widely used in many traditional chemical industry fields and have also shown great application prospects in emerging fields. This review aims to provide an overview of the recent advances in alumina and its supported Pd-based catalysts. Specifically, the synthesis strategies, morphology transformation mechanisms, and structural properties of alumina with various morphologies are comprehensively summarized and discussed in-depth. Then, the preparation approaches of Pd/Al2O3 catalysts (impregnation, precipitation, and other emerging methods), as well as the metal-support interactions (MSIs), are revisited. Moreover, Some promising applications have been chosen as representative reactions in fine chemicals, environmental purification, and sustainable development fields to highlight the universal functionality of the alumina-supported Pd-based catalysts. The role of the Pd species, alumina support, promoters, and metal-support interactions in the enhancement of catalytic performance are also discussed. Finally, some challenges and upcoming opportunities in the academic and industrial application of the alumina and its supported Pd-based are presented and put forward.

Morphology dependent effect of γ-Al2O3 for ethanol dehydration: nanorods and nanosheets

γ-Al2O3 nanorods gave the improved selectivity of C2H4 in ethanol dehydration due to the selective exposure of {100} facets.

In situ growth of layered double hydroxides on boehmite AlOOH for active and stable oxygen evolution in alkaline media

Among all the non-precious electrocatalysts for the oxygen evolution reaction (OER), FeNi and FeCo layered double hydroxides (LDHs) display the best activity. However, due to the unavoidable transformation of the active M3+/4+ (M = Fe, Co, and Ni) ions into inert M-O-H species, their activity dramatically decreases after about 25 h during stability tests, which means the widely-adopted stability test with a duration of 24 h is not sufficient for LDHs. Herein, the in situ growth of Fe1Co1 and Fe1Ni1 LDH nanosheets on V- and Ni-doped AlOOH nanorods was extended for the duration of stable electrocatalysis to 50 h. The V and Ni dopants were found to promote the diffusion of active Fe, Co and Ni cations along the abundant {100} planes of AlOOH single-crystalline nanorods with their {100} family of crystal planes perpendicular to the lateral facet, avoiding the aggregation of the active species and their transformation into inert species and their following nucleation and growth. Besides, the nano-channels on the nanorods generated during the subsequent in situ growth of LDHs are beneficial for the supply of OH- and the transportation of O2, which enhance the activity and stability of these composites.

γ-Al2O3 nanorods with tuneable dimensions – a mechanistic understanding of their hydrothermal synthesis

This paper reports mechanistic understanding of the hydrothermal synthesis of alumina (γ-Al₂O₃) nanorods, presenting an economic and reproducible route for their manufacture with tuneable sizes for a wide range of applications.

The solvothermal synthesis of γ-AlOOH nanoflakes and their compression behaviors under high pressures

The compression behaviors of γ-AlOOH nanoflakes were investigated via in situ high pressure synchrotron radiation angle dispersive X-ray diffraction techniques.

A facile, green and efficient surfactant-free method for synthesis of aluminum nanooxides with an extraordinary high surface area

Nano boehmite with unprecedented high surface area and pore volume (802 m² g⁻¹, 2.35 cm³ g⁻¹) was prepared using a facile, green and efficient surfactant-free synthesis method.