A study of the mechanism of triglyceride hydrodeoxygenation over alumina-supported and phosphatized-alumina-supported Pd catalysts

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.

The Effect P Additive on the CeZrAl Support Properties and the Activity of the Pd Catalysts in Propane Oxidation

The properties of a catalyst support are closely related to the catalyst activity, yet the focus is often placed on the active species, with little attention given to the support properties. In this work, we specifically investigated the changes in support properties after the addition of P, as well as their impact on catalyst activity when used for catalyst preparation. We prepared the CeO2-ZrO2-P2O5-Al2O3 (CeZrPAl) composite oxides using the sol-gel, impregnation, and mechanical mixing methods, and characterized the support properties using techniques such as XRD, XPS, SEM-EDS, N2 adsorption-desorption, and Raman spectra. The results showed that the support prepared using the sol-gel method can exhibit a more stable phase structure, larger surface area, higher adsorption capacity for oxygen species, and greater oxygen storage capacity. The addition of an appropriate amount of P is necessary. On the one hand, the crystallization and growth of CePO4 can lead to a decrease in the Ce content in the cubic phase ceria-zirconia solid solution, resulting in a phase separation of the ceria-zirconia solid solution. On the other hand, CePO4 can lock some of the Ce3+/Ce4+ redox pairs, leading to a reduction in the adsorption of oxygen species and a decrease in the oxygen storage capacity of the CeZrPAl composite oxides. The research results indicated that the optimal P addition is 6 wt.% in the support. Therefore, we prepared a Pd/CeZrPAl catalyst using CeZrAl with 6 wt.% P2O5 as the support and conducted the catalytic oxidation of C3H8. Compared with the support without P added, the catalyst activity of the support loaded with P was significantly improved. The fresh and aged (1000 °C/5 h) catalysts decreased by 20 °C and 5 °C in T50 (C3H8 conversion temperature of 50%), and by 81 °C and 15 °C in T90 (C3H8 conversion temperature of 90%), respectively.

Indigenous Materials as Catalyst Supports for Renewable Diesel Production in Malaysia

High energy demand from the market due to the rapid increment of the human population worldwide has urged society to explore alternatives to replace non-renewable energy. Renewable diesel produced from biomass could be the next potential energy source for its high stability, long-term storage, and comparable performance with diesel fuels. In producing renewable diesel, the application of catalyst is essential, and the catalyst support is synthesized with the catalyst to enhance the reaction rate and catalytic properties. In this review, the type of catalyst support will be reviewed along with a brief introduction to biodiesel and renewable diesel production, especially focusing on zeolites as the catalyst support. The enhancement of catalyst support will be critically discussed to improve the catalytic performance of support in renewable diesel production and important aspects such as the stability and recyclability of the supported catalyst are included. The application of the supported catalyst in increasing the selectivity and yield of renewable diesel is significant, in which the catalytic properties depend on the interaction between catalyst and catalyst support. The supported catalyst as a favorable substance to assist in enhancing renewable diesel yield could lead to a sustainable and greener future for the biofuel industry in Malaysia.