Poisoning-tolerant metal hydride materials and their application for hydrogen separation from CO2/CO containing gas mixtures

Abstract

Modibane, K.D. et al. (2013). Poisoning-tolerant metal hydride materials and their application for hydrogen separation from CO2/CO containing gas mixtures. AbstractMetal hydride materials offer attractive solutions in addressing problems associated with hydrogen separation and purification from waste flue gases. However, a challenging problem is the deterioration of hydrogen charging performances resulting from the surface chemical action of electrophilic gases. In this work, the feasibility study of poisoning tolerance of surface modified AB5-type hydride forming materials and their application for hydrogen separation from process gases containing carbon dioxide and monoxide was carried out. Target composition of La(Ni,Co,Mn,Al)5 substrate was chosen to provide maximum reversible hydrogen capacity at the process conditions. The selected substrate alloy has been shown to be effectively surface-modified by fluorination followed by electroless deposition of palladium. The surface-modified material exhibited good coating quality, high cycle stability and minimal deterioration of kinetics of selective hydrogen absorption at room temperature, from gas mixtures containing 10% CO2 and up to 100 ppm CO. The experimental prototype of a hydrogen separation unit, based on the surfacemodified metal hydride material, was tested and exhibited stable hydrogen separation and purification performances when exposed to feedstocks containing concentrations of CO21. Introduction Metal hydride (MH) materials have found a number of promising gas-phase applications in processes of considerable economic potential, such as hydrogen storage, separation and recovery, thermally-driven compressors and heat pumps, etc. [1e3]. These materials exhibit a favourable combination of their properties, including reversibility and selectivity of interaction with H 2 gas at mild conditions, high volumetric density of hydrogen in the solid, significant heat effects in the course of hydrogenation/dehydrogenation. Thus they are very flexible in the applications, and often allow to develop multifunctional facilities (e.g., for hydrogen storage, purification and controlled supply) which offer to an end-user safe, efficient and cost-saving solutions [4].

Metal hydride technologies for renewable energy

“…Surface modification (fluorination, electroless deposition, etc.) of metal hydrides was applied to improve poisoning tolerance against CO and CO2 [30,31,[38][39][40]. Our research team [41] showed practical applicability of metal hydride technology for biohydrogen separation from different gas compositions.…”

“…Main disadvantage is low gravimetric density, which does not exceed 1 -2 %wt., but it is not significant limitation for stationary applications [12,17]. To current date, there are a number of practical application of metal hydrides in hydrogen storage systems [18][19][20][21], hydrogen compression [22-28], hydrogen purification [29][30][31].…”

Carbon monoxide poisoning and mitigation strategies for polymer electrolyte membrane fuel cells – A review

“…27 More recently, it was found that the reaction rate is dependent on the surface structure and the electrolyte. 28,29 For the most common anode catalyst, platinum, the rate of hydrogen oxidation depends on the crystal orientation following the trend Pt (110)>Pt (100)>Pt (111). The Tafel reaction is the rate-limiting step in the case of Pt(110): 30,31 + ↔ − (Tafel reaction) (1)…”

Hydrogen purification methods

“…X-ray photoelectron spectroscopy results confirmed that the bond between Ni and CO was formed by a simple chemisorptions process, rather than forming nickel carbonyl. Modibane et al (2013) studied the deterioration of AB 5 type hydride in hydrogen purification from gases containing carbon dioxide (up to 30%) and monoxide (up to 100 ppm). The substrate La(Ni, Co Mn, Al) 5 was surface-modified by fluorination followed by electroless deposition of palladium.…”