Doped Ni Catalysts for Methane Reforming with CO2

Abstract

Pb, Sb, Bi and Te doped Ni catalysts were prepared and used for methane reforming with CO 2 in order to diminish coke deposition. It was found that small amounts of Pb doped Ni catalysts exhibited excellent coke resistance ability with minor loss of the reforming activity. As the added amount of Pb increased from 0 to 0.015 (mole ratio between Pb/Ni), coke formation rate decreased from 166.7 mg-coke/g-cat h (on Ni/SiO 2 ) to 0, while the reforming activity decreased slightly from 73.2% to 63.3% (conversion of CO 2 ) at 800°C, 60,000 ml(STP)/g-catÁh (CH 4 CO 2 =1:1, no dilution gas in feed). Higher amounts of Pb and Sb, Bi, Te made Ni catalyst deactivated for methane reforming with CO 2 .

Controlling Selectivity and Stability in the Hydrocarbon Wet-Reforming Reaction Using Well-Defined Ni + Ga Intermetallic Compound Catalysts

“…Each of these approaches clearly limits rehydrogenation kinetics by modifying the stability of carbonaceous or atomic H intermediates or the fundamental nature of the hydrogen-surface bond. A similar trend has been identified in prior studies by others and ourselves in the surface chemistry of TM solid compounds formed from TMs combined with similarly sized p-block elements. ,, Elevated kinetic barriers for H-transfer have been connected to the nature of the H-surface bond and the presence of covalent-like bonding within the TM solid compound as a function of the selective or full hybridization between the d- and p-states of constituent elements. ,,, This effect may help to avoid the unselective loss of H, but may also detrimentally affect H 2 evolution rates in reforming reactions. The studies presented herein clarify the beneficial effect of this newly accessible surface chemistry.…”

“…Many prior studies have focused on limiting coke, TM carbide, and carbon nanotube (CNT) formation through the addition of secondary elements to a late TM metal like Ni to attenuate C/CH x supply at the catalyst surface. ,,,− For example, the addition of mostly inactive coinage metals (Au or Ag) or large p-block elements (Bi) has been shown to block over-reactive sites via a simple physical effect. − ,, Stability could also be improved by reducing the rate of C–H activation in comparison to that of the over-reactive sites of pure Ni through the addition of more reactive TMs and f-block elements. For example, the addition of Fe, Mo, Co, or Rh results in the lower overall catalytic activity in comparison to that of Ni at t = 0 TOS but improved stability.…”

“…Because the added elements limit coke deposition, their overall activity at steady state is often higher than that of pure Ni. ,− When doping late TMs with large p-elements (Sn, Pb, Te, etc.) that form oxides too stable to cycle in composition under reaction conditions, the over-reactive site blocking or electronic modifications of the general surface chemistry likely limit C–H activation and coke deposition. ,,,− …”

Characterization of NiO–Al2O3 composite and its conductivity in biogas for solid oxide fuel cell

“…Therefore, it has widely been used in various industrial processes [3][4][5][6]. Furthermore, these composites have also developed renewed interest in their partial applications in CO 2 reduction [7,8], as a protective barrier, as electrochromic materials in smart windows [9], in sensors [10] as surface layers and in toughening processes [11].…”

Characteristics of the Decomposition of CO2 in a Dielectric Packed-Bed Plasma Reactor

“…Among the methods for the reduction of CO 2 , the reforming of CO 2 and hydrocarbons has attracted great interests in the past decades because of the mitigation of greenhouse gases and better carbon resource recycling utilization [1]. Generally, reforming reactions of CO 2 and hydrocarbons are carried out by thermal catalysis, and the catalysts are usually supported metals, including supported noble metals and Ni-based catalysts [2][3][4][5]. However, dry reforming reactions require high temperatures to overcome the unfavorable thermodynamic equilibrium.…”