On the mechanism of oxidative degradation of rhodamine B over LaFeO3 catalysts supported on silica materials: Role of support

Abstract

On the mechanism of oxidative degradation of rhodamine B over LaFeO 3 catalysts supported on silica materials: Role of support, Microporous and Mesoporous Materials (2015), AbstractThis work aims to investigate the role of silica support in the catalytic oxidation of rhodamine B (RhB) over LaFeO 3 -Silica composites. Four LaFeO 3 -Silica composites using mesoporous silica (SBA-15, SBA-16, MCF) and nano-sized silica powder (NSP) as supports are prepared. XRD, N 2 physisorption isotherms and TEM results show that pure LaFeO 3 phase, with particle size of 15-20 nm, is prepared and the texture of supports remains unchanged after the deposition of LaFeO 3 .Catalytic results show that, besides the function to disperse LaFeO 3 on the surface, the support plays two important roles in the reaction: one is to absorb RhB from solution to the pores of support, and the other is to transport RhB from the pores to the active site, both influence the catalytic efficiency. Thus the non-porous NSP with negligible capacity for RhB adsorption is the worst, and the MCF with considerable capacity for RhB adsorption and the strongest ability to transport RhB to the active site is the best support of LaFeO 3 for RhB oxidation. SBA-15 and SBA-16, although show considerable or even higher capacity for RhB adsorption relative to MCF, their contribution to the reaction is less due to the low efficiency of transporting RhB to the active site. On these bases, the role of silica support in RhB oxidation conducted over LaFeO 3 -Silica composite is proposed.

Adsorption and photo-Fenton catalytic degradation of organic dyes over crystalline LaFeO3-doped porous silica

“…This suggests that both of the LFO-doped catalysts could adsorb RhB from solution onto the silica support and guarantee the degradation to occur smoothly on the LFO active sites. 24 As can be seen above, the plain silica support HPS-0LFO could remove RhB to some level, mainly governed by adsorption (~65% shown in Fig. 6a).…”

Aerobic selective oxidation of alcohols using La1−Ce CoO3 perovskite catalysts

“…Very often they are used for reactions carried out at high temperatures, such as purification of exhaust gases [19,20]. Recent reports show that perovskites are also active in reactions carried out at mild temperatures, such as the room-temperature oxidation of organic dyes by H 2 O 2 , although they are less active for H 2 O 2 decomposition [21]. This shows that the ability of perovskites to activate H 2 O 2 can be improved in the presence of an organic substrate, which can coordinate with the transition metals of the perovskite and influence the electronic structure of the metal-oxygen bond, improving H 2 O 2 activation.…”

“…In view of the above, and given our past experience with perovskites [17,[21][22][23][24][25], we attempted to investigate if these oxides would also have the ability to activate molecular oxygen and subsequently catalyze the oxidation of organic substrates into desired fine chemicals at mild temperatures. Given the strong affinity of Ce 4+ to oxygen [22], La 1Àx Ce x CoO 3 (0 6 x 6 1.5) catalysts were prepared by a sol-gel method using methanol and ethylene glycol as complexing agents, with calcination at 600°C for 5 h. The LaCoO 3 activity and the efficiency for aerobic oxidation of alcohols at mild temperatures (e.g., 88°C) were compared with those of materials with cerium incorporated into the framework.…”

A Visible Light-Driven Zn/Cr-LaFeO3 Nanocomposite with Enhanced Photocatalytic Activity towards H2 Production and RhB Degradation

“…According to Li et al. the composites of LFO and Silica also showed tremendous activity towards RhB degradation under visible light irradiation . Similarly different groups also reported different photocatalytic activity of the neat and composites of LFO towards both water splitting as well as organic pollutant degradation which is explained in the section 4.…”