Octahedral Mn_(3)O_(4)nanoparticles with an Ag-doping and nanoporous Ag(NPS)framework was simply fabricated through an alloying-etching engineering.The dual-modified Mn_(3)O_(4)(denoted as Ag−Mn_(3)O_(4)/NPS)consists ...Octahedral Mn_(3)O_(4)nanoparticles with an Ag-doping and nanoporous Ag(NPS)framework was simply fabricated through an alloying-etching engineering.The dual-modified Mn_(3)O_(4)(denoted as Ag−Mn_(3)O_(4)/NPS)consists of Ag-doped Mn_(3)O_(4)nanoparticles crosslinked with three dimensional nanoporous Ag framework.The incorporated Ag dopant is effective in improving the intrinsic ionic and electronic conductivities of Mn_(3)O_(4),while the NPS framework is introduced to improve the electron/mass transfer across the entire electrode.Profiting from the dual-modification strategy,the Ag−Mn_(3)O_(4)/NPS exhibits admirable rate capability and cycling stability.A high reversible capacity of 88.7 mA·h/g can still be retained for over 1000 cycles at a current density of 1 A/g.Moreover,a series of ex-situ experimental techniques indicate that for Ag−Mn_(3)O_(4)/NPS electrode during the zinc ion storage,Mn_(3)O_(4)is electrochemically oxidized into various MnOx(e.g.,Mn_(2)O_(3),MnO2)species in the initial charging,and the subsequent battery reaction is actually the intercalation/deintercalation of H+and Zn2+into MnOx.展开更多
A continuous online in situ attenuated total reflection Fourier-transform infrared(ATR-FTIR)spectroscopic technique was used to investigate the adsorption and desorption kinetics of heptyl xanthate(KHX)on the surface ...A continuous online in situ attenuated total reflection Fourier-transform infrared(ATR-FTIR)spectroscopic technique was used to investigate the adsorption and desorption kinetics of heptyl xanthate(KHX)on the surface of ZnO and Cu(Ⅱ)activated ZnO.The results showed that Cu(Ⅱ)facilitated the xanthate adsorption process on the surface,and led to the formation of cuprous xanthate(CuX),dixanthogen(X_(2))and xanthate aggregates.The adsorption of xanthate on the surface of ZnO and Cu(Ⅱ)activated ZnO was found to both follow the pseudo-first-order kinetic model.When the NaOH solution was used as a desorption agent,the adsorbed xanthate can largely be removed due to the competition between OH^(−)and HX−.However,for Cu(Ⅱ)activated ZnO,the peak intensities at 1197 and 1082 cm^(−1) had no obvious weakening,and the absorption intensities at 1261 and 1026 cm^(−1) increased in the first 5 min,indicating an ion-exchange reaction between OH^(−)and surface zinc bonded xanthate HX−and the reorganization of adsorbed xanthate.展开更多
Developing non‐noble‐metal electrocatalyst with efficient and durable activity is a urgent task for addressing the sluggish reaction kinetics of electrochemical water oxidation.Structural evolution of the electrocat...Developing non‐noble‐metal electrocatalyst with efficient and durable activity is a urgent task for addressing the sluggish reaction kinetics of electrochemical water oxidation.Structural evolution of the electrocatalyst is an important strategy for achieving enhanced performance.Herein,in situ evolution of surface Co_(2)CrO_(4) to CoOOH/CrOOH(CoOOH/CrOOH‐Co_(2)CrO_(4))by an electrochemical method under alkaline conditions was designed for enhancing the electrocatalytic performance of water oxidation.The experiments demonstrated that the synergy between CoOOH/CrOOH and Co_(2)CrO_(4) resulted in a marked increase in the number of active sites and improved the rate of charge transfer,which enhanced the activity for water oxidation.At a geometrical current density of 20 mA cm^(−2),the overpotential of the oxygen evolution reaction was 244 mV and the turnover frequency was 0.536 s^(−1) in 1.0 M NaOH.展开更多
基金financially supported by the Natural Science Foundation of Shandong Province,China (Nos.ZR2023ME155,ZR2023ME085)the National Natural Science Foundation of China (No.52201254)+1 种基金the Project of“20 Items of University”of Jinan,China (No.202228046)the Taishan Scholar Project of Shandong Province,China (No.tsqn202306226)。
文摘Octahedral Mn_(3)O_(4)nanoparticles with an Ag-doping and nanoporous Ag(NPS)framework was simply fabricated through an alloying-etching engineering.The dual-modified Mn_(3)O_(4)(denoted as Ag−Mn_(3)O_(4)/NPS)consists of Ag-doped Mn_(3)O_(4)nanoparticles crosslinked with three dimensional nanoporous Ag framework.The incorporated Ag dopant is effective in improving the intrinsic ionic and electronic conductivities of Mn_(3)O_(4),while the NPS framework is introduced to improve the electron/mass transfer across the entire electrode.Profiting from the dual-modification strategy,the Ag−Mn_(3)O_(4)/NPS exhibits admirable rate capability and cycling stability.A high reversible capacity of 88.7 mA·h/g can still be retained for over 1000 cycles at a current density of 1 A/g.Moreover,a series of ex-situ experimental techniques indicate that for Ag−Mn_(3)O_(4)/NPS electrode during the zinc ion storage,Mn_(3)O_(4)is electrochemically oxidized into various MnOx(e.g.,Mn_(2)O_(3),MnO2)species in the initial charging,and the subsequent battery reaction is actually the intercalation/deintercalation of H+and Zn2+into MnOx.
基金supported by the National Natural Science Foundation of China (Nos.51274104,50874052)the National Basic Research Program of China (No.2011CB933700)。
文摘A continuous online in situ attenuated total reflection Fourier-transform infrared(ATR-FTIR)spectroscopic technique was used to investigate the adsorption and desorption kinetics of heptyl xanthate(KHX)on the surface of ZnO and Cu(Ⅱ)activated ZnO.The results showed that Cu(Ⅱ)facilitated the xanthate adsorption process on the surface,and led to the formation of cuprous xanthate(CuX),dixanthogen(X_(2))and xanthate aggregates.The adsorption of xanthate on the surface of ZnO and Cu(Ⅱ)activated ZnO was found to both follow the pseudo-first-order kinetic model.When the NaOH solution was used as a desorption agent,the adsorbed xanthate can largely be removed due to the competition between OH^(−)and HX−.However,for Cu(Ⅱ)activated ZnO,the peak intensities at 1197 and 1082 cm^(−1) had no obvious weakening,and the absorption intensities at 1261 and 1026 cm^(−1) increased in the first 5 min,indicating an ion-exchange reaction between OH^(−)and surface zinc bonded xanthate HX−and the reorganization of adsorbed xanthate.
文摘Developing non‐noble‐metal electrocatalyst with efficient and durable activity is a urgent task for addressing the sluggish reaction kinetics of electrochemical water oxidation.Structural evolution of the electrocatalyst is an important strategy for achieving enhanced performance.Herein,in situ evolution of surface Co_(2)CrO_(4) to CoOOH/CrOOH(CoOOH/CrOOH‐Co_(2)CrO_(4))by an electrochemical method under alkaline conditions was designed for enhancing the electrocatalytic performance of water oxidation.The experiments demonstrated that the synergy between CoOOH/CrOOH and Co_(2)CrO_(4) resulted in a marked increase in the number of active sites and improved the rate of charge transfer,which enhanced the activity for water oxidation.At a geometrical current density of 20 mA cm^(−2),the overpotential of the oxygen evolution reaction was 244 mV and the turnover frequency was 0.536 s^(−1) in 1.0 M NaOH.