Characterization of Al2O3 Supported Nickel Catalysts Derived from RF Non-thermal Plasma Technology

Abstract

Catalysts derived from non-thermal plasma techniques have previously shown unusual and highly advantageous catalytic properties including room temperature reduction, unusual metal particle structure and metalsupport interactions, and enhanced selectivity and stability. This study focuses on the characterization of Al 2 O 3 supported Ni catalysts derived from the RF non-thermal plasma technique with in-situ XRD, TPR-MS and STEM and on relating the results to the enhanced activity and stability of benzene hydrogenation. The results suggest that catalysts with plasma treatments before impregnation are relatively easier to be reduced and result in better activities under mild reduction conditions. These plasma treatments stabilize the nickel particle sizes of air(B) and H 2 (B) catalysts at 600°C by slowing down the sintering process. Plasma treatments after the impregnation of precursors, on the other hand, tend to delay the growth of nickel particles below 600°C, forming smaller Ni particles, but with a sudden increase in particle size near 600°C. It suggests that the structure of Ni nitrate and the metal-support interaction have been altered by the plasma treatments. The reduction patterns of plasma treated catalysts are, therefore, changed. The catalyst with a combination plasma treatment demonstrates that the effect of a combination plasma treatment is larger than either the plasma treatment before or after the impregnation alone. Both plasma treatments before and after the impregnation of metal precursor play important roles in modifying supported metal catalysts.

Synthesis of Boehmite Hollow Core/Shell and Hollow Microspheres via Sodium Tartrate-Mediated Phase Transformation and Their Enhanced Adsorption Performance in Water Treatment

“…Boehmite is an aluminum oxyhydroxide, which is the main precursor for production of γ-Al 2 O 3 used in catalysis, adsorption, coating technologies, and in the preparation of alumina-based materials. , Boehmite can also be used as an orthopedic or a dental material due to its biocompatibility . Owing to its thermal, chemical, and mechanical stabilities as well as catalytic and textural properties well-suited for both catalysis and adsorption, preparation of γ-Al 2 O 3 with high surface area, tailored porosity, and controlled morphology attracted the attention of many researchers. ,− However, well-crystallized boehmite usually gives γ-Al 2 O 3 with low surface area, whereas in most cases, the boehmite used in catalysis (often called pseudoboehmite) is poorly crystallized, less ordered, and does not contain intercalated water in the structure. − Therefore, it is still a great challenge to develop simple and efficient strategies for the synthesis of boehmite with controlled physicochemical properties (crystallinity, morphology, textural properties, etc.) …”

Cold Plasma Produced Catalytic Materials

“…The plasma treatment is also engaged in appropriate adaptation of catalytic supports through developing their surfaces and increasing the catalyst dispersion. For example, the study focused on Al 2 O 3 -supported Ni catalysts suggests that the catalysts with Al 2 O 3 subjected to plasma treatment before impregnation are relatively easier to reduce and exhibit higher activities under mild reduction conditions [45].…”

Intensification of a hydrogenation catalyst activity by nanosecond pulsed discharge treatment

“…Catalyst treatment via non‐thermal plasma can improve catalyst performance . Plasma active species (i.e., electrons, ions, radicals, and excited species) interact with catalyst surface imposing physical (structural) and chemical modifications such as high active metal dispersion, unique particle structure and strong metal–support interactions . Recent works have revealed that plasma‐treated catalysts exhibit improved acetylene conversion and ethylene selectivity as compared to fresh ones, likely due to enhanced active metal dispersion and modified metal‐support interaction.…”

“…Although plasma‐induced catalyst activity enhancement has been shown in the literature, the impact of individual plasma parameters on catalyst activity is rather unexplored. Herein, we focus and report on the individual impact of pulse voltage, pulse frequency and treatment time on catalyst activity.…”