Physico-Chemical nanomaterials science

Catalytic oxidation of hydrogen over nanoscale gold and platinum metals
Klimchuk V.Yu.1, Boldyrieva O.Yu.1, Zaporozhets O.A.1, and Lisnyak V.V.1
1 Chemical Department, Taras Shevchenko University of Kyiv, Volodymyrska Str., 64, Kyiv-01601, Ukraine. 
E-mail: ob@univ.kiev.ua

Catalysis with nanoscale supported noble metals is a prominent direction for the development in the renewable and green energy industry. Hydrogen is the known fuel of the future; but, its safe use is still an actual problem because of reasons related to hydrogen storage. Recombination catalysts for H2–O2 reaction become required since numerous hydrogen leakages can be caused the external fire and explosion. In this situation, the use of passive converter that recombines hydrogen by low-temperature catalytic oxidation and works on nanoscale supported noble metals seems to be a brilliant solution. However, at preparing of oxidation catalysts by impregnation methods, we rarely get high-dispersed particles because of the lack of induced interaction between the noble metal salts used as a precursor and the oxide support, which allows mobility of the precursor salt during drying and reduction. To solve this issue, we prepared a series of catalysts containing nanosized metal particles by a specially elaborated technique. The morphologic studies of nanoparticles were performed with SEM, HRTEM, AFM, and STM methods. Also, we investigated kinetic aspects of the hydrogen oxidation over nanoscale noble metals. The prepared catalysts showed sufficient adsorption of H2 and O2 molecules to be warranted for detailed consideration, and we considered the reason for the observed effective adsorption. Spillover and thermal hysteresis phenomena registered in the course of catalytic experiments with H2–air gas mixtures [1] were disclosed, and their reasons were suggested. The catalysts based on nanoscale supported noble metals can completely eliminate H2 from H2–air mixtures even at zeroth temperatures.

1.	Volovenko O.B., Zaporozhets O.A., Lisnyak V.V., Boldyrieva O.Yu. Platinum surface complexes as precursors for H2–O2 recombination catalysts. // Adsorption Sci Technol.-2017.-35.-P. 735-743.