The Effect of Noble Metal (M: Ir, Pt, Pd) on M/Ce2O3-γ-Al2O3 Catalysts for Hydrogen Production via the Steam Reforming of Glycerol

Abstract

A promising route for the energetic valorisation of the main by-product of the biodiesel industry is the steam reforming of glycerol, as it can theoretically produce seven moles of H2 for every mole of C3H8O3. In the work presented herein, CeO2–Al2O3 was used as supporting material for Ir, Pd and Pt catalysts, which were prepared using the incipient wetness impregnation technique and characterized by employing N2 adsorption–desorption, X-Ray Diffraction (XRD), Temperature Programmed Reduction (TPR), Temperature Programmed Desorption (TPD), X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). The catalytic experiments aimed at identifying the effect of temperature on the total conversion of glycerol, on the conversion of glycerol to gaseous products, the selectivity towards the gaseous products (H2, CO2, CO, CH4) and the determination of the H2/CO and CO/CO2 molar ratios. The main liquid effluents produced during the reaction were quantified. The results revealed that the Pt/CeAl catalyst was more selective towards H2, which can be related to its increased number of Brønsted acid sites, which improved the hydrogenolysis and dehydrogenation–dehydration of condensable intermediates. The time-on-stream experiments, undertaken at low Water Glycerol Feed Ratios (WGFR), showed gradual deactivation for all catalysts. This is likely due to the dehydration reaction, which leads to the formation of unsaturated hydrocarbon species and eventually to carbon deposition. The weak metal–support interaction shown for the Ir/CeAl catalyst also led to pronounced sintering of the metallic particles.

Recent Advances in Glycerol Catalytic Valorization: A Review

“…The production of H 2 has gained a huge amount of interest in the last decades, as it is a potential clean energy fuel [57]. In this route, there are several technologies employed, such as gasification, steam reforming [211,255], dry reforming [100,256], pyrolysis, and aqueous phase reforming [257] (see Section 3.3). The drawbacks of reforming are the drastic reaction conditions (atmospheric pressure and temperature < 800 • C) and many side reactions and the production of CO 2 .…”

Main Hydrogen Production Processes: An Overview

“…The use of glycerol in reforming processes is very promising; it can theoretically provide seven moles of hydrogen for every mole of C 3 H 8 O 3 [55], moreover glycerol is a by-product of biodiesel production, whose commercial value has been strongly affected by excessive supply. The use of glycerol for the production of value-added chemicals, such as hydrogen, appears to be the best way to exploit it and simultaneously increase the global biodiesel market [56].…”

“…The use of glycerol for the production of value-added chemicals, such as hydrogen, appears to be the best way to exploit it and simultaneously increase the global biodiesel market [56]. Even in the case of glycerol steam reforming, the noble metal-based catalysts show excellent performance [57], in particular excellent activity has been found with Pt-based catalysts [55], moreover the presence of promoters suppresses the coke formation, however the high cost makes them uncompetitive compared to nickel-based catalysts [58].…”

Catalytic Oxidation of Glycerol over Pt Supported on MOF-Derived Carbon Nanosheets

“…In recent years, biodiesel has attracted increasing attention as a renewable energy source. − Consequently, biodiesel production has continually increased and so has the quantity of glycerol generated as a byproduct . Therefore, it is important to develop means of effectively transforming glycerol into high-value-added products, such as selective oxidation, , steam reforming reaction, − hydrogenolysis, , transesterification and pyrolysis . which could reduce the production cost of biodiesel while improving the associated economics.…”