Degradation of nitrobenzene(NB)via Fenton-like reaction is considered as an efficient approach for contaminated groundwater remediation.However,the poor stability of H2O2limits the application of traditional Fenton re...Degradation of nitrobenzene(NB)via Fenton-like reaction is considered as an efficient approach for contaminated groundwater remediation.However,the poor stability of H2O2limits the application of traditional Fenton reactions in soil and groundwater due to the transportation risks of H_(2)O_(2).In this study,we synthesized a controlled release nano calcium peroxide(n CP)by coating it with polydopamine(PDA)as a solid H2O2to construct a Fe(Ⅱ)/PDA@n CP Fenton-like system for contaminants degradation.The phenolquinone transformations of catechol groups on the PDA surface facilitated the Fe(Ⅱ)/Fe(Ⅲ)cycle,resulting in enhanced generation of hydroxyl radicals(HO·)and effective long-term degradation of NB.Moreover,the PDA shell modulated the n CP decomposition rate and inhibited sharp p H fluctuations,and the NB removal efficiency was achieved up to 96.8%at p H ranging from 3.0 to 9.0.This study demonstrated the promising application potential of PDA@n CP as a solid-controlled release H2O2source in Fenton-like system for groundwater contamination remediation.展开更多
Three supported Ir/TiO_(2)catalysts,containing anatase TiO_(2)nanocrystals with predominantly exposed{101},{100},and{001}planes,were subjected to various pre-treatments(H2 reduction at different temperatures and O_(2)...Three supported Ir/TiO_(2)catalysts,containing anatase TiO_(2)nanocrystals with predominantly exposed{101},{100},and{001}planes,were subjected to various pre-treatments(H2 reduction at different temperatures and O_(2)re-oxidation)and then tested in the vapor phase selective hydrogenation of crotonaldehyde.The pre-treatments significantly altered the Ir-TiO_(x)interactions,including the morphologies and electronic properties of the Ir species and their surface acidity.These interactions were also closely related to the crystal planes of TiO_(2),which further supported the observed reaction behaviors of the various Ir/TiO_(2)catalysts.The best performance was obtained using the Ir/TiO_(2)-{101}catalyst pre-reduced at 300℃,owing to its higher Ir^(0)surface concentration and moderate surface acidity compared to the other catalysts.Moreover,these findings indicated the synergistic role of the Ir-TiO_(x)interface in the reaction,as the interfacial sites were responsible for the adsorption/activation of H_(2)and the C=O bond in the crotonaldehyde molecule.However,pre-reduction at 400℃resulted in partial encapsulation of the Ir particles by TiO_(x)via strong metal-support interactions,which is unfavorable for the catalytic reaction owing to the loss of Ir-TiO_(x)interfacial sites.展开更多
Pt/ZrO_(2)catalysts promoted with MoO_(3)and Nb_(2)O_(5)were tested for the combustion of short-chain alkanes(namely,methane,ethane,propane,and n-hexane).For short-chain alkane combustion,the inhibition of MoO_(3)(for...Pt/ZrO_(2)catalysts promoted with MoO_(3)and Nb_(2)O_(5)were tested for the combustion of short-chain alkanes(namely,methane,ethane,propane,and n-hexane).For short-chain alkane combustion,the inhibition of MoO_(3)(for the methane reaction)dramatically transformed to promotion(for the ethane,propane,and n-hexane reactions)as the carbon chain length increased,whereas the remarkable promotion of Nb_(2)O_(5)gradually weakened with an increase in the carbon chain length.Based on a detailed study of the oxidation reactions of methane and propane over the catalysts,the different roles of the promoters in the reactions were ascribed to differences in the acidic properties of the surface and the oxidation or reduction states of the Pt species.The MoO_(3)promoter could decorate the surface of the Pt species for a Pt-Mo/ZrO_(2)catalyst,whereas the Nb_(2)O_(5)promoter on the support could be partially covered by Pt particles for a Pt-Nb/ZrO_(2)catalyst.The formation of accessible Pt-MoO_(3)interfacial sites,a high concentration of metallic Pt species,and a high surface acidity in Pt-Mo/ZrO_(2)were responsible for the enhanced activity for catalytic propane combustion.The lack of enough accessible Pt-Nb_(2)O_(5)interfacial sites but an enhanced surface acid sites in Pt-Nb/ZrO_(2)explained the slight improvement in activity for catalytic propane combustion.However,the stabilized Pt^(n+)species in Pt-Nb/ZrO_(2)were responsible for the much-improved activity for methane combustion,whereas the Pt^(n+)species in Pt-Mo/ZrO_(2)could be reduced during the oxidation reaction,and the fewer exposed surface Pt species because of MoO_(3)decoration accounted for the inhibited activity for methane combustion.In addition,it can be concluded that MoO_(3)promotion is favorable for the activation of C-C bonds,whereas Nb_(2)O_(5)promotion is more beneficial for the activation of C-H bonds with high energy.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42077185,U22A20591)the Sichuan Science and Technology Program for Distinguished Young Scholars(Nos.2022JDJQ0010,2022ZYD0040)+1 种基金the National Key Research and Development Program of China(No.2020YFC1808300)the Research Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(No.SKLGP2020Z002)。
文摘Degradation of nitrobenzene(NB)via Fenton-like reaction is considered as an efficient approach for contaminated groundwater remediation.However,the poor stability of H2O2limits the application of traditional Fenton reactions in soil and groundwater due to the transportation risks of H_(2)O_(2).In this study,we synthesized a controlled release nano calcium peroxide(n CP)by coating it with polydopamine(PDA)as a solid H2O2to construct a Fe(Ⅱ)/PDA@n CP Fenton-like system for contaminants degradation.The phenolquinone transformations of catechol groups on the PDA surface facilitated the Fe(Ⅱ)/Fe(Ⅲ)cycle,resulting in enhanced generation of hydroxyl radicals(HO·)and effective long-term degradation of NB.Moreover,the PDA shell modulated the n CP decomposition rate and inhibited sharp p H fluctuations,and the NB removal efficiency was achieved up to 96.8%at p H ranging from 3.0 to 9.0.This study demonstrated the promising application potential of PDA@n CP as a solid-controlled release H2O2source in Fenton-like system for groundwater contamination remediation.
文摘Three supported Ir/TiO_(2)catalysts,containing anatase TiO_(2)nanocrystals with predominantly exposed{101},{100},and{001}planes,were subjected to various pre-treatments(H2 reduction at different temperatures and O_(2)re-oxidation)and then tested in the vapor phase selective hydrogenation of crotonaldehyde.The pre-treatments significantly altered the Ir-TiO_(x)interactions,including the morphologies and electronic properties of the Ir species and their surface acidity.These interactions were also closely related to the crystal planes of TiO_(2),which further supported the observed reaction behaviors of the various Ir/TiO_(2)catalysts.The best performance was obtained using the Ir/TiO_(2)-{101}catalyst pre-reduced at 300℃,owing to its higher Ir^(0)surface concentration and moderate surface acidity compared to the other catalysts.Moreover,these findings indicated the synergistic role of the Ir-TiO_(x)interface in the reaction,as the interfacial sites were responsible for the adsorption/activation of H_(2)and the C=O bond in the crotonaldehyde molecule.However,pre-reduction at 400℃resulted in partial encapsulation of the Ir particles by TiO_(x)via strong metal-support interactions,which is unfavorable for the catalytic reaction owing to the loss of Ir-TiO_(x)interfacial sites.
文摘Pt/ZrO_(2)catalysts promoted with MoO_(3)and Nb_(2)O_(5)were tested for the combustion of short-chain alkanes(namely,methane,ethane,propane,and n-hexane).For short-chain alkane combustion,the inhibition of MoO_(3)(for the methane reaction)dramatically transformed to promotion(for the ethane,propane,and n-hexane reactions)as the carbon chain length increased,whereas the remarkable promotion of Nb_(2)O_(5)gradually weakened with an increase in the carbon chain length.Based on a detailed study of the oxidation reactions of methane and propane over the catalysts,the different roles of the promoters in the reactions were ascribed to differences in the acidic properties of the surface and the oxidation or reduction states of the Pt species.The MoO_(3)promoter could decorate the surface of the Pt species for a Pt-Mo/ZrO_(2)catalyst,whereas the Nb_(2)O_(5)promoter on the support could be partially covered by Pt particles for a Pt-Nb/ZrO_(2)catalyst.The formation of accessible Pt-MoO_(3)interfacial sites,a high concentration of metallic Pt species,and a high surface acidity in Pt-Mo/ZrO_(2)were responsible for the enhanced activity for catalytic propane combustion.The lack of enough accessible Pt-Nb_(2)O_(5)interfacial sites but an enhanced surface acid sites in Pt-Nb/ZrO_(2)explained the slight improvement in activity for catalytic propane combustion.However,the stabilized Pt^(n+)species in Pt-Nb/ZrO_(2)were responsible for the much-improved activity for methane combustion,whereas the Pt^(n+)species in Pt-Mo/ZrO_(2)could be reduced during the oxidation reaction,and the fewer exposed surface Pt species because of MoO_(3)decoration accounted for the inhibited activity for methane combustion.In addition,it can be concluded that MoO_(3)promotion is favorable for the activation of C-C bonds,whereas Nb_(2)O_(5)promotion is more beneficial for the activation of C-H bonds with high energy.
