Page 6 - JES202006
P. 6

2                           jour nal o f e nvironmental sciences 92 (2020) 1 e10


          gas shift reaction, and hydrogenation reactions (Bai et al.,  other creatures due to its toxicity and difficulty in degradation.
          2014; Cui et al., 2015; Chen et al., 2017; Wu et al., 2017). The  While, its reduction product, p-aminophenol (PAP), can be
          metal-support interaction, especially the strong metal-  involved in various fields including drugs, developing agent,
          support interaction, can induce the phenomenon that elec-  polymers, agrochemicals, pigments, and dyes. So it is of great
          tron transfer from support to metal, and thus the geometric or  importance to realize the conversion of PNP to PAP (Tafesh and
          electronic property of catalysts can be significantly altered,  Weiguny, 1996; Shi et al., 2010; Li et al., 2012, 2015; Qiao et al.,
          which shows a substantial influence on catalytic activity and  2017; Karki et al., 2018). The hydrogenation reduction of PNP by
          stability (Yuan et al., 2018). Surface facets, surface polariza-  NaBH 4 is thermodynamically feasible only with the aid of
          tion, oxygen vacancy and so on have been identified as valid  appropriate catalysts (Khalavka et al., 2009; Zhang et al., 2012;
          strategies to modify electronic structures of materials, which  Huang et al., 2012b; Antonels and Meijboom, 2013; Fu et al.,
          are attributed to the efficiency of interfacial interaction (Sun  2013; Johnson et al., 2013; Kalekar et al., 2013; Liao et al., 2016).
          et al., 2010; Huang et al., 2012a; Bao et al., 2015).  Numerous reports focus on the synthesis and the activity of
             The support in the synthesized heterogeneous catalysts  various catalysts, but the catalytic properties for the reduction of
          plays a significant role to catalytic activity because of its in-  PNPbyAg/Fe 2 O 3 with specific morphology were rarely reported.
          ternal properties such as morphology, components, oxygen  Herein, we prepared three different Ag/Fe 2 O 3 composites
          vacancy, and so on (Schubert et al., 2001; Li et al., 2013). The  with different support morphologies including nanoplates
          mechanism about the interfacial interaction between metal  (NPs), nanospheres (NSs), and nanocubes (NCs). The reduction
          and the support, especially the reducible oxides, for example,  of PNP with excessive reductant under ambient condition was
          TiO 2 , CeO 2 ,Fe 2 O 3 , have been widely investigated (Ou et al.,  chosen to evaluate the catalytic activity. The catalytic activ-
          2011; Liu et al., 2012; Yuan et al., 2018). Zhao et al. (2016) re-  ities of three catalysts showed obvious. Diverse measure-
          ported a novel composite catalyst with different crystal facets  ments were carried out to investigate the morphology
          used as supports for selective catalytic reduction of NO with  dependence of the hematite support. The high performance of
          NH 3 , and discovered that the TiO 2 nanosheets supported  Ag/Fe 2 O 3 NPs could be attributed to the strong electron
          catalyst showed much better activity, stability and durability  interaction between Ag and plate-like Fe 2 O 3 at their interface.
          than the TiO 2 nanoparticles supported catalyst. Larsen et al.
          (2016) investigated the catalytic performance of Au deco-
          rated Fe 2 O 3 catalyst with different shapes, including spheres,  1.  Materials and methods
          rings, and tubes, using a similar methods, which confirmed
          that the supports with specific morphology determined the  1.1.  Materials and reagents
          catalytic performance. To demonstrate the effect of metal-
          support interaction, the CO oxidation was catalyzed by Pt/  Allreagentswereofanalyticalgrade andusedwithout further
          FeO x catalyst obtained via using a co-precipitation method, in  purification. Iron chloride hexahydrate (FeCl 3 $6H 2 O), Fe 2 O 3
          which its high performance was attributed to the synergetic  nanospheres (Fe 2 O 3 NSs), sodium acetate, sodium oleate, oleic
          effect of surface FeO x and Pt (Xu et al., 2018). Recently, Chen et  acid, ethanol, sodium borohydride, silver nitrate, p-nitrophenol
          al. (2020) reported that three kinds of Au nanoparticles with  were purchased from Sinopharm Group Chemical Reagent Co.
          different morphologies, including Au nanospheres (Au-NSs),  Ltd., China. Deionized water (18 MU,cm) from a Millipore Q
          Au nanorods (Au-NRs) and Au nanopentogons (Au-NPs), were  water  purification  system  was  used  throughout  the
          prepared and used as photosensitizers to modify TiO 2 hollow  experiments.
          nanoboxes to enhance the photocatalytic activity, which
          ascribe the best performance to the surface plasma resonance  1.2.  Preparation of Fe 2 O 3 nanocrystals
          (SPR) effect of Au-NRs.
             The reduction potential of Ag decreases due to the  Fe 2 O 3 NPs and NCs were prepared with different hydrother-
          increased Fermi potential, which makes it possible to be uni-  mal and solvothermal methods as previously reported (Wang
          versally applied in the electron transfer process (Saha et al.,  et al., 2007; Chen et al., 2010).
          2010). The state of Ag, including the geometric or electronic  For the preparation of Fe 2 O 3 NPs, 1.09 g of FeCl 3 $6H 2 O was
          properties, may be altered due to the effect of the support or  added to the mixed solution consist of 40.0 mL ethanol and
          the metal-support interaction. For Ag/CeO 2 catalysts with  2.8 mL deionized water. And then 3.2 g of sodium acetate was
          various morphologies including nanorods, nanoparticles, and  added to the mixture with magnetic stirring until completely
          nanocubes, the catalytic activities primarily relayed on the  dissolved. After that, the mixture was transferred into a
          morphologies of the support, which was on account of the  100 mL Teflon-lined stainless steel autoclave, and heated at

          surface oxygen vacancy concentration produced by the  180 C for 12 hr. The red precipitate was collected, and washed
          interfacial interaction between Ag and CeO 2 with different  thoroughly by deionized water, and ethanol, respectively.
          morphologies (Yu et al., 2018). When Ag/MnO 2 catalysts with  Finally, the obtained product was dried at 40 C for 12 hr.

          different morphologies (wire-like, rod-like and tube-like) were  Fe 2 O 3 NCs were synthesized by a reported solvothermal
          used for the toluene oxidation, it was demonstrated that the  method. In brief, 5.33 g sodium oleate, 27 mL of ethanol, 4.3 mL
          morphology of the support significantly affected the state of  of oleic acid, and 23 mL of water were mixed together, and then
          Ag and the metal-support interaction, thus determining the  1.6 g of FeCl 3 $6H 2 O was added to the solution. After stirring for
          activity (Li et al., 2016).                         2 hr, the mixture was transferred into a 100 mL Teflon-lined

             p-Nitrophenol (PNP), one of the common organic pollution  stainless steel autoclave, and heated at 180 C for 12 hr. Until
          existing in the wastewater, can cause damage to human and  cooling to ambient temperature, the product was collected,
   1   2   3   4   5   6   7   8   9   10   11