The tailored chemical synthesis of binary and ternary alloy nanoparticles with a uniform elemental composition is presented. Their dual use as magnetic susceptors for induction heating and catalytic agent for steam reforming of methane to produce hydrogen at temperatures near and above 800 °C is demonstrated. The heating and catalytic performance of two chemically synthesized samples of CoNi and Cu⊂CoNi are compared and held against a traditional Ni-based reforming catalyst. The structural, magnetic, and catalytic properties of the samples were characterized by X-ray diffraction, elemental analysis, magnetometry, and reactivity measurements. For induction-heated catalysts, the conversion rate of methane is limited by chemical reactivity, as opposed to the case of traditional externally heated reformers where heat transport limitations are the limiting factor. Catalyst production by the synthetic route allows controlled doping with miniscule concentrations of auxiliary metals.
The tailored chemical synthesis of binary and ternary alloy nanoparticles with a uniform elemental composition is presented. Their dual use as magnetic susceptors for induction heating and catalytic agent for steam reforming of methane to produce hydrogen at temperatures near and above 800 °C is demonstrated. The heating and catalytic performance of two chemically synthesized samples of CoNi and Cu⊂CoNi are compared and held against a traditional Ni‐based reforming catalyst. The structural, magnetic, and catalytic properties of the samples were characterized by X‐ray diffraction, elemental analysis, magnetometry, and reactivity measurements. For induction‐heated catalysts, the conversion rate of methane is limited by chemical reactivity, as opposed to the case of traditional externally heated reformers where heat transport limitations are the limiting factor. Catalyst production by the synthetic route allows controlled doping with miniscule concentrations of auxiliary metals.
Induction heating by magnetic hysteresis of nanoparticles inside chemical reactors is an interesting approach for direct and electrified heating of high-temperature endothermic catalytic reactions. Here, we show how it is possible to tune the induction heating for steam methane reforming by use of aluminasupported Co x Ni (100−x) nanoparticles with well-defined alloy compositions from x = 20 to 90. The ∼30 nm Co−Ni particles function both as a catalyst and as an induction heating susceptor. We find that induction heating increases with increasing Ni content at lower temperatures and smaller induction fields due to Ni being magnetically softer than Co, but the maximum heating temperature increases with Co content due to the Curie temperature being higher for Co than for Ni. Specifically, the Curie temperature of the sample increases with the Co content and sets for each alloy a hard limit to the maximum operation temperature in the induction-heated reactor. Furthermore, the reaction rate increases with increasing Ni content. The compromise between magnetic softness, Curie temperature, and catalytic activity leads to an optimum Co−Ni sample composition at a given operating temperature and induction field amplitude. Based on the results, Co−Ni compositions can be selected in order to tune heat transport and reaction kinetics down through a reactor to optimize the reactor performance. Moreover, Co−Ni composition can be chosen such that the Curie temperature prevents overheating.
The use of naturally occurring quinones to produce more
sustainable
electrolytes to use for renewable energy storage in redox flow batteries
(RFBs) is still a new and rarely investigated subject. In this study,
we demonstrate how the putative phoenicin and its dimer (diphoenicin)
influence the capacity performance of phoenicin as a negolyte in a
redox flow battery. To do this, we biosynthesized phoenicin by cultivating
the filamentous fungus Penicillium phoeniceum and the resulting fungal extract contained multiple metabolites,
putatively related to phoenicin, including the proposed phoenicin
dimer, which constituted 7% of the extract. When paired with potassium
ferri/ferrocyanide as a posolyte in an RFB, the battery showed an
initial capacity of 1.58 Ah L–1. In contrast to
our previous study, this corresponded to a two-electron reaction per
benzoquinone group. A detailed electrochemical and chemical analysis
is conducted to shed light on this discrepancy and to provide further
insight into the chemical stability of phoenicin in an alkaline environment
(pH = 14).
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