Catalytic Steam-Reforming of Glycerol over LDHs-Derived Ni-Al Nanosheet Array Catalysts for Stable Hydrogen Production

Abstract

In the present work, LDHs–derived Ni–Al nanosheet arrays (NiAl/NA) were successfully synthesized via a one–step hydrothermal method, and applied in the steam-reforming of glycerol reaction for enhanced and stable hydrogen production. The physicochemical properties of catalysts were characterized using various techniques, including XRD, SEM–EDS, XPS, N2–physisorption, Raman, and TG–DTG. The results indicate that smooth and cross–linked Ni–Al mixed metal oxide nanosheets were orderly and perpendicularly grown on the Ni foam substrate. The SEM line scan characterization reveals the metal concentration gradient from the bottom to the top of nanosheet, which leads to distinctly optimized Ni valence states and an optimized binding strength to oxygen species. Owing to the improved reducibility and more exposed active sites afforded by its array structures, the NiAl/NA catalyst shows enhanced glycerol conversion (83.1%) and a higher H2 yield (85.4%), as well as longer stability (1000 min), compared to the traditional Ni–Al nanosheet powder. According to the characterization results of spent catalysts and to density functional theory (DFT) calculations, coke deposition is effectively suppressed via array construction, with only 1.25 wt.% of amorphous carbons formed on NiAl/NA catalyst via CO disproportionation.

Glycerol Steam Reforming in a Pilot Plant: Effect of Temperature and Catalyst Load

“…It should be noted that similar studies with Ni/CaO-Al 2 O 3 at different Ni loadings (from 2.5 to 20% wt) offered an optimum Ni loading of 15%, with a high glycerol conversion (99.4% at 700 • C) [46]. In addition, other works offered a high glycerol conversion and yields (83 and 85%, respectively) through the catalytic steam reforming of glycerol over an LDH-derived Ni-Al nanosheet [42].…”

“…Catalytic steam reforming of glycerol over LDH-derived Ni-Al nanosheet to obtain stable hydrogen production High glycerol conversions (exceeding 83%) were achieved, with a high H 2 yield (85%) and a long catalyst stability (1000 min). [42] Effect of noble metals on Ce…”