Feasibility of hydrogen production from steam reforming of biodiesel (FAME) feedstock on Ni-supported catalysts

The catalytic steam reforming of biodiesel was examined over Ni-alumina and Ni-ceria-zirconia catalysts at atmospheric pressure. Effects of temperatures of biodiesel preheating/ vapourising (190-365 °C) and reforming (600-800 °C), molar steam to carbon ratio (S/C=2-3), , and residence time in the reformer, represented by the weight hourly space velocity ‘WHSV’ of around 3 were examined for 2h. Ni supported on calcium aluminate and on Ceria-zirconia supports achieved steady state hydrogen product stream within 90% of the equilibrium yields, although 4% and 1% of the carbon feed had deposited on the catalysts, respectively, during the combined conditions of start-up and steady state. Addition of dopants to ceria-zirconia supported catalyst decreased the performance of the catalyst. Increase in S/C ratio had the expected positive effects of higher H2 yield and lower carbon deposition

Durability of CaO–CaZrO₃ Sorbents for High-Temperature CO₂ Capture Prepared by a Wet Chemical Method

Powders of CaO sorbent modified with CaZrO have been synthesized by a wet chemical route. For carbonation and calcination conditions relevant to sorbent-enhanced steam reforming applications, a powder of composition 10 wt % CaZrO/90 wt % CaO showed an initial rise in CO uptake capacity in the first 10 carbonation-decarbonation cycles, increasing from 0.31 g of CO/g of sorbent in cycle 1 to 0.37 g of CO/g of sorbent in cycle 10 and stabilizing at this value for the remainder of the 30 cycles tested, with carbonation at 650 C in 15% CO and calcination at 800 C in air. Under more severe conditions of calcination at 950 C in 100% CO, following carbonation at 650 C in 100% CO, the best overall performance was for a sorbent with 30 wt % CaZrO/70 wt % CaO (the highest Zr ratio studied), with an initial uptake of 0.36 g of CO/g of sorbent, decreasing to 0.31 g of CO /g of sorbent at the 30th cycle. Electron microscopy revealed that CaZrO was present in the form of ≤0.5 μm cuboid and 20-80 nm particles dispersed within a porous matrix of CaO/CaCO; the nanoparticles are considered to be the principal reason for promoting multicycle durability

Perovskite Oxide Catalysts for Advanced Oxidation Reactions

Published online: May 16, 2021Meeting the escalating demand for clean water resources is one of the key challenges to ensure a sustainable future. Catalysis plays an important role to advance the chemical reactions required for wastewater efficient remediation. How to exploit high-performance catalysts to boost the pivotal reaction kinetics always attracts researchers’ enthusiasm. Perovskite oxides as a novel class of functional materials can be tuned to confer compositional flexibilities and provide rich and unique structural properties. As the rising-star material, it has been widely probed for electrocatalysis, photocatalysis, and membrane- catalysis for energy conversion, but received less attention in water treatment. In this review, the advances of perovskite oxides for advanced oxidation processes (AOPs) in water remediation are comprehensively elaborated. A fundamental understanding of the crystal structures and properties of perovskite oxides as well as the basic principles of AOPs is firstly provided. Then, emphasis is placed on how to tune the perovskite oxides to suit various AOPs. The strategies to design novel perovskite oxides to enhance the catalytic activities in AOPs have been highlighted. It is expected that after reading this review, readers will have a clearer vision of the background, the state of the art development, and general guidelines for future directions regarding research in this area.Kai Wang, Chen Han, Zongping Shao, Jieshan Qiu, Shaobin Wang, and Shaomin Li