Various metal oxides as promoters were also reported inliterature such as MgO, CeO2 and La2O3. According toTomishige et al. [23], addition of MgO to Pt/Ni/CeO2/Al2O3catalyst formed NiOeMgO solid solution which helped todisperse Ni particles. They [24e27] also reported similar phenomenon using CeO2 as the promoter for Ni-based catalystwhere the Ni and CeO2 formed a strong interaction and thisinteraction played a very important role on the catalytic activity of the catalyst and suppression of coke deposition inbiomass gasification. Furthermore, La2O3 was also widelyknown to improve the catalyst activity and stability [28,29] asreported in steam reforming of naphthalene [13], steam gasification of pine sawdust [30], steam reforming of bio-oil [31],and steam reforming of toluene [32].Mineral catalysts such as dolomite (CaMg(CO3)2) andolivine ((Mg,Fe)2SiO4) have been getting much attention due toits cheap cost. However, the activity of dolomite and olivine toreduce tar concentration in biomass gasifier is still belowexpectation [33e36]. In addition, dolomite also has problem inpoor attrition resistance. Therefore, they can only be used forguard bed to lower down the tar concentration before passingto expensive catalyst for total tar removal. Addition of Ni or Feon the olivine [34e38], dolomite, and basic metal oxide such asCaO [39] have been reported to enhance the catalytic activityin steam reforming of tar.It is clearly shown in literature that development of catalyst for steam reforming of toluene for hydrogen productionshould use Ni, Co or Fe as the catalyst with basic metal oxide(such as MgO and CaO) as the catalyst support in order toreduce carbon formation rate which is the main problem insteam reforming of toluene. From an economic point of view,Ni and Fe catalysts are preferred than Co catalyst. Therefore,in this study, combination between Ni and Fe with La as thecatalyst support is utilized since La2O3 support is a basic metaloxide and it has been reported to increase the activity of steamreforming of bio-oils, steam gasification of pine sawdust [30]and steam reforming of naphthalene [13] and help to reducethe rate of carbon deposition on the catalyst surface [28,29]. Inorder to elucidate the effect of Fe addition on Ni catalyst,perovskite catalyst synthesized by solegel method is chosenover impregnation method since perovskite catalyst is a welldefined mixed oxide catalyst with general chemical formulaABO3, in which after reduction, can produce uniform metalparticles. The catalytic performance of perovskite catalyst interms of activity and stability is studied for hydrogen production via steam reforming of tar with toluene as a modelcompound of tar. Various characterizations of fresh, reduced,and spent catalysts are also performed to elucidate the effectof Fe addition to Ni catalyst in catalyst performance.
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