• Membrane Journal
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• v.28 no.5
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• pp.297-306
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• 2018

This review focused carbon-free hydrogen productions from ammonia decomposition including inorganic membranes, catalysts and the presently studied reactor configurations. It also contains general information about hydrogen productions from hydrocarbons as hydrogen carriers. A Pd-based membrane (e.g. a porous ceramic or porous metallic support with a thin selective layer of Pd alloy) shows its efficiency to produce the high purity hydrogen. Ru-based catalysts consisted of Ru, support, and promoter are the efficient catalysts for ammonia decomposition. Packed bed membrane reactor (PBMR), Fluidized bed membrane reactor (FBMR), and membrane micro-reactor have been studied mainly for the optimization and the improvement of mass transfer limitation. Various types of reactors, which contain various combinations of hydrogen-selective membranes (i.e. Pd-based membranes) and catalysts (i.e. Ru-based catalysts) including catalytic membrane reactor, have been studied for carbon-free hydrogen production to achieve high ammonia conversion and high hydrogen flux and purity.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.3
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• pp.260-266
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• 2018

To enhance catalyst activity of the palladium (Pd) towards oxygen reduction reaction (ORR), iridium (Ir) and yttrium (Y) were alloyed by polyol method. Due to the low reduction potential of Y, it is hard to reduce Y ion completely by polyol method. In XPS spectra, the binding energy of the Pd is shifted to a lower value, which indicates the d-electron of Pd is filled by the electron from the Y. And other phases of Y are observed by the XPS. Among the catalysts, the $Pd_4IrY_{0.1}/C$ showed the best activity towards ORR, which indicates the metallic Y is effective for improving the catalytic activity. Thus, for further enhancing ORR activity, the novel method for complete reduction of Y is needed.