ABSTRACT
Against the background of escalating global electronic waste (e-waste) and its rich reservoir of elements, this research addresses the exploitation of precious metals from discarded CPUs for potential applications in hydrogen production. The study systematically explores the influence of varied CPU sample preparation techniques on the formation of an electrode's catalytic layer and the kinetics of the hydrogen evolution reaction (HER) in alkaline media. Four distinct e-waste samples, each subjected to different preparation protocols, were employed as sources in electrodeposition baths. The electrocatalytic efficiency of the resulting electrodeposited cathodes was evaluated, with the AR-CPU-1.4M electrode demonstrating superior properties. Morphological insights from SEM, coupled with elemental data from EDS and ICP analyses, revealed the intricate relationship between sample preparation, electrode characteristics, and HER kinetics. Notably, gold deposits and a prominent copper concentration emerged as defining attributes of our findings. This research underscores the potential of e-waste-derived metals, particularly in hydrogen production, providing an avenue for sustainable metal recovery and utilization.
ABSTRACT
Green hydrogen produced by alkaline electrolysis is a promising solution to address the world's increasing energy demand while mitigating greenhouse gas emissions. However, the efficient and cost-effective production of green hydrogen via alkaline electrolysis requires improvements. This paper presents an in situ activation process that simplifies the alkaline electrolysis technology while enhancing the catalytic activity of electrodes for the hydrogen evolution reaction. The aim of this research is to enhance the energy efficiency of alkaline electrolysis and decrease the energy consumption for hydrogen production. To achieve this goal, ionic activators comprising Ni, Zn, and Mo were incorporated into the standard electrolyte solution. Our results demonstrate that the anticipated improvement in the catalytic activity of the d-metal combination, surpassing even that of precious metals, has been successfully attained. As a result, a 20% reduction in energy consumption (REC) for the hydrogen produced has been observed. The catalytic activity of the added activators for the hydrogen evolution reaction was discussed by analyzing the mechanism of the reaction via Tafel analysis and EIS techniques. These findings offer a promising approach to improve alkaline electrolysis and enhance the production of green hydrogen.
ABSTRACT
The capacitance and operating voltage of supercapacitors as well as their energy density have been increased by development of different materials and electrolytes. In this paper, two strategies, for the first time, were used to improve energy density: Mn3O4- and N-dual doped carbon electrode and aqueous mixture of multivalent ions as electrolyte. Mn3O4- and N-dual doped carbon was prepared by a novel and cost-effective procedure using deep eutectic solvent. XRD, XPS, and FTIR confirmed presence of Mn3O4 and nitrogen, while SEM and EDS elemental mapping showed micrometer-sized nanosheets with uniform distribution of C, O, N, and Mn atoms. Charge storage behavior of carbon was tested in aqueous multivalent-based electrolytes and their mixture (Ca2+-Al3+). Regarding both specific capacitance and workable voltage, the Ca2+-Al3+ mixed electrolyte was found as the best optimal solution. The calcium addition to the Al-electrolyte allows the higher operating voltage than in the case of individual Al(NO3)3 electrolyte while the addition of Al3+ ion in the Ca(NO3)2 electrolyte improves the multivalent-ion charge storage ability of carbon. As a result, the specific energy density of two-electrode Mn3O4@N-doped carbon//Al(NO3)2+Ca(NO3)2//Mn3O4@N-doped carbon supercapacitor (34 Wh kg-1 at 0.1 A g-1) overpasses the reported values obtained for Mn-based carbon supercapacitors using conventional aqueous electrolytes.
ABSTRACT
BACKGROUND: Niemann Pick type C is an autosomal recessive lysosomal storage disorder caused by mutations in NPC1 and NPC2 genes. It is a neuro-visceral disease with a heterogeneous phenotype. Clinical features depend on the age at onset. Visceral manifestations are more prominent in the early onset (infantile) form, while neuro-psychiatric symptoms are more prominent in the late disease onset (juvenile and adult forms). METHODS: A total number of 150 patients have been screened for changes in NPC1 and NPC2 gene at the Neurology Clinic, University Clinical Centre of Serbia in the period 2012-2020. Clinical data were extracted for patients with biallelic mutations. RESULTS: Fifteen patients carried biallelic mutations in the NPC1. Out of eight different reported NPC1 variants, four are novel (c.1204_1205TT>GC, p.F402A; c.2486T>G, p.L829R; c.2795+5 G>C; c.3722T>A, p.L1241*). The mean age at the disease onset was 20.3 ± 11.9 years with the average diagnostic delay of 7.7 ± 4.3 years. Movement disorders and psychiatric or cognitive disturbances were the most common initial symptoms (in 33% and 28% patients, respectively). The average age at the first neurological manifestation was 21 ± 12.0 years. At the last examination, eye movement abnormalities (vertical slow saccades or vertical supranuclear gaze palsy), and ataxia were present in all patients, while dystonia was common (in 78.6% of patients). Presence of c.2861C>T, p.S954L mutation in homozygous state was associated with older age at the neurological symptom onset. CONCLUSIONS: Clinical findings were in line with the expected, but the diagnostic delay was common. We hypothesize that the presence of c.2861C>T, p.S954L mutation may contribute to the phenotype attenuation.
