The advantage of n-type semiconductor for an anode of solid oxide fuel cells (SOFCs) lies in its higher electronic conductivity in reducing atmosphere than in air. In this study, n-type FeNbO4-based oxides that can be reduced at temperatures below 700 o C for a conductivity above 1 S cm -1 are explored as anode materials for a ceria-based SOFC utilizing liquefied-petroleum-gas (LPG) fuel apart from pure H2. Fe0.8Nb1.2O4 with 20 at.% Fe deficiency was founded in the sample sintered at 1250 o C. The structure stability of FeNbO4 under reducing atmosphere can be improved by its solid solution with a lessreducible TiO2 that also stabilizes the high-temperature -PbO2 type structure with mixed Fe 3+ and Nb 5+ cation. In particular, a full cell employing Ti0.36(Fe0.985Nb1.015)0.84O4, a stable and electrically conductive (1 S cm -1 ) oxide in 5% H2, as anode shows a powder density of 180 mW cm -2 at 700 o C if 0.5 wt.% Pd is impregnated to increase the electrocatalysis and the electric loss is mostly from the electrolyte. The oxide anode showed a degradation (20% during the 5 to 26 hours aging) and the carbon deposition is slight after 5-hour operation under an LPG fuel.[1] and are not restrained by efficiency limitations applicable to heat engines (i.e. the Carnot cycle). The potential widespread use of SOFCs also depends on the availability of fuel[2]. Comparing to the low-temperature proton-exchange-membrane fuel cell (PEMFC), the advantage of an all-ceramic SOFC device could be the ability to use carbonaceous fuel, i.e. carbon monoxide, methane et al., other than pure H2 fuel[3-6]. The fuel versatility of an SOFC increases the fuel availability since the infrastructure for carbonaceous fuel is mature, which will facilitate the commercialization of this technique and reduce the additional cost on H2 storage and transport[2]. The conventional nickelbased anode catalyzing the oxidation of the H2 fuel on GDC electrolyte is Ni(O)-GDC cermet and a high performance (e.g. 2 W cm 2 at 550 o C)[7] has been achieved via the optimization of the cathode materials and the thinning of the electrolyte[8]. However, the carbon deposition or coking process of the Ni under a carbonaceous fuel would prohibit the long-term operation for continuous power supply[9] and thus novel oxide perovskites, such as (La, Sr)(Cr, Mn)O3, Sr2MoMO6 (M=Mg, Cr or Mn) and (La, Sr)TiO3, has been developed for the operation under hydrocarbon fuels[10-20].Generally, both nand p-type semiconducting oxides can be used as the anode materials in an SOFC. La0.75Sr0.25Cr0.5Mn0.5O3 is a paradigmatic p-type semiconducting oxide showing a decreased conductivity under reducing atmosphere of fuel than in air, while (La, Sr)TiO3 is an n-type semiconductor showing superior stability and conductivity if is fully reduced[21] at elevated temperatures [22] (above 750 o C under H2). However, an SOFC under the intense in-situ reduction at elevated temperature for anodes can possibly induce the reduction of the GDC electrolyte, causing the increase of electronic conduction and i...

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Effect of mineral nutrients in biomass was found to be crucial in the synthesized carbon dots, affecting their dispersibility, PL stability and crystallinity.

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