Reforming of Glycerol

Biodiesel production has grown, between 2005 and 2015, at almost 25% per annum (reaching approximately 32 billion liters), leading to a seven-fold expansion of the sector. Although biodiesel is thought of as a renewable, biodegradable, environmentally-friendly fuel, there are concerns over the production of glycerol, the main by product of the transesterification reaction (it accounts for 10% of the volume of oil undergoing the reaction).

An innovative option is the energetic utilization of glycerol via steam reforming (SR), as every mole of glycerol fed to the reactor can theoretically produce seven moles of hydrogen. At LAFEC we have devoted our efforts towards the design of appropriate catalysts based on transition metals that can be used in the GSR. In some of our previous works, we reported on the performance of different transition metals (Ni, Co, Cu) on silica [BioResources 11 (2016) 10173-89] and alumina [Fuel Process Technol 152 (2016) 156-75], of Ni catalysts based on alumina, zirconia, silica [Top Catal 60 (2017) 1226-50] and apatite-type lanthanum silicates supports [RSC Adv 6 (2016) 78954-8], the influence of the synthesis method on Ni/Al catalysts [Chinese J Catal 37 (2016) 1949-65], the effect of the addition of lanthana on Ni/Al catalysts [Int J Hydrogen Energ 42 (2017) 13039-60], the effect of the addition of CaO-MgO on Ni/Al catalysts [Int J Hydrogen Energ 44 (2019) 256-273], the use of AlCeO₃ as supporting material for a Ni catalyst [Catalysts 9 (2019) 411], the effect of the addition of silica [Top Catal 60 (2017) 1226-1250] or yttria [Int J Hydrogen Enrg, In press] on Ni/ZrO₂ catalysts. We have also tested Ce-Sm-xCu [Sust Energ Fuels 3 (2019) 673-691] and Ni/Ce-Sm-xCu [Nanomaterials 8 (2018) 931] catalysts. A comprehensive literature review with particular focus on the main catalysts and support systems under development has also been carried out [Surf Coat Technol 352 (2018) 92-111].

Moreover, we have also examined glycerol reforming via chemical looping using Ni/ZrO₂ nano-composite oxygen carriers [Int J Hydrogen Energ 43 (2018) 13200-11].

CO₂ Utilization - Biogas Dry Reforming

It is well understood that human activities, emanating from current practices relating to the production and consumption of fossil based energy have an unequivocal impact upon the global climate. A promising technology is the Dry Reforming of Biogas, as the process makes use of the main greenhouse gases (CH₄ and CO₂), and can provide a renewable resource with a potential zero carbon footprint. The product of this process is syngas, a key chemical feedstock for the synthesis of oxygenated chemicals and hydrocarbons from Fisher – Tropsch synthesis.

At LAFEC we have examined the performance of nickel catalysts based on alumina modified with ceria, lanthana [J Nat Gas Sci Eng 31 (2016) 164-83 & Catal Today 195 (2012) 93-100], magnesia or calcium [Waste Biomass Valori 7 (2016) 725-36]. A theoretical investigation of Ni-Al₂O₃ and Ni/CeO₂-Al₂O₃ has also been performed [Int J Hydrogen Energ 35 (2010) 9818-27].

We have also devoted effort in investigating the performance of Nickel catalysts based on zirconia modified with ceria, lanthana [Int J Hydrogen Energ 42 (2017) 13724-40] and tugsten [Front Environ Sci 5 (2017) 66]. Moreover, we have examined different synthesis techniques in an effort to maximize the dispersion of active phase and optimize the active species [Catal Today 46, 175-83; Int J Hydrogen Energ 40 (2015) 9183-00].

Finally, we have committed ourselves at investigating the carbonaceous species formed during the reaction [J Catal 161, 626-40; Adv Mater Proc 2 (2017) 807-12; Mater Today: Proc. 5 (2018) 27607-27616; Int J Hydrogen Energ 43 (2018) 18955-18976; Appl Surf Sci 474 (2019) 42-56], as it is one of the main reasons for catalyst deactivation.

NO_x and SO₂ abatement

Nitrogen and sulphur oxide abatement is a subject of major environmental importance, as Nitric (NO_x) and Sulphur (SO_x) oxides are recognized as important precursors of acid rain, contributors to the formation of photochemical smog and to the destruction of the ozone layer. Recently, a lot of academic and policy attention has focused on N₂O emissions control. Nitrous oxide (N₂O) is listed as one of the most harmful greenhouse gases with a strong global warming potential (310 times higher than that of CO₂), that severely contributes to the stratospheric ozone layer depletion.

At LAFEC, we were the first to investigate the lean NO_x reduction by propene, H₂ as well as by propene + H₂ over supported (on γ-Al₂O₃), low loading (0.5 wt%), Pt, Pd and Ir catalysts [J Environ Chem Eng 4 (2016) 1629-41]. In addition, we have examined the impact of alkali promoters (K) on the physicochemical properties and catalytic performance of Ir/Al₂O₃ catalysts towards the N₂O decomposition [Top Catal 59 (2016) 1020-7]. Finally, we have examined the deactivation and regeneration procedures of copper oxide catalysts/sorbents that are supported on Al₂O₃, SiO₂, CeO₂-Al₂O₃, in the presence of SO₂ and identified the appropriate conditions for the simultaneous removal of NO and SO₂ [Global Nest J 14 (2012) 166-74].