Size Limit of Support Particles in an Oxide-Supported Metal Catalyst:  Nanocomposite Ni/ZrO₂ for Utilization of Natural Gas

Abstract

This paper explores the size effect of zirconia particles on the catalysis of Ni metal for CO2 re-forming of methane. It is revealed for the first time that when the sizes of zirconia particles become samller than 25 nm, the oxide forms nanocomposite catalysts with size-comparable Ni-metal nanocrystals (10−15 nm). The nanocomposite catalysts show extremely stable catalysis, which is in strong contrast with the deactivating Ni catalyst supported on bigger zirconia particles (>25 nm). This raises the possibility of tailoring the catalytic behavior of oxide-supported metal catalysts by reducing the particle size of oxide to make high-performance nanocomposite catalysts.

Comparative study of atmospheric and high pressure CO2 reforming of methane over Ni/MgO-AN catalyst

“…This characteristic catalyst behavior in the high-pressure reaction can be termed as a selfstabilization of the catalyst since no external force was exerted during the reaction. Because of the unavoidable reverse water-gas shift reaction (CO 2 + H 2 = CO + H 2 O), it can be expected that the actual conversion of CO 2 should be higher than that of CH 4 in the reaction [11,36]. Clearly, the catalytic results in figure 1 are consistent with this expectation, the conversion of methane (83.0%) being lower than that of CO 2 (86.5%).…”

Catalysis by Gold: Isolated Surface Au3+ Ions are Active Sites for Selective Hydrogenation of 1,3‐Butadiene over Au/ZrO2 Catalysts

“…[24] Samples of Au/ZrO 2 were prepared by loading the support with appropriate amounts of Au by the deposition-precipitation method with HAuCl 4 precursor, [8] the concentration of which was adjusted to yield catalysts containing 0.76, 0.23, 0.05, and 0.01 wt % Au (ICP-AES analysis). The 0.76 % Au/ZrO 2 sample was treated with an aqueous solution of KCN in a process similar to that reported by Fu et al [11] to give 0.08 % Au/ZrO 2 catalyst.…”

Performance of Ni/MgO–AN catalyst in high pressure CO2 reforming of methane

“…This characteristic performance of the catalyst can be termed as a self-stabilization of the catalyst in the high-pressure reaction since no external force was exerted during the reaction and the stabilized activity was kept unchanged at TOS longer than 50 h. It is interesting to notify that the conversion of CH 4 at the very beginning of the reaction (TOS £ 2 h) is higher than that of the CO 2 reactant, e.g. the conversions of CH 4 and CO 2 are 37.5 and 32.6%, respectively, at TOS ¼ 1 h. Because of the unavoidable reverse watergas shift reaction (CO 2 + H 2 fi CO + H 2 O), the conversion of CO 2 should usually be higher than that of CH 4 in the reaction [27,29]. This abnormal phenomenon indicates that the conversion of CH 4 was not balanced by the CO 2 conversion or there was an ''excessive'' conversion of CH 4 at the beginning of the reaction.…”