The anode reaction and current density of the electrowinning of Sb from jamesonite concen- trate have been investigate.High anodic current density seems to be the major reason for high energy consumption,air pollution...The anode reaction and current density of the electrowinning of Sb from jamesonite concen- trate have been investigate.High anodic current density seems to be the major reason for high energy consumption,air pollution by alkaline mists in workshop as well as poor quality of deposition.A series of steps,such as absorption,phase formation,ageing of passivated films etc.,were found to be involved during the anodic passivating process of Fe in NaOH solution. A new anodic material Fe/Ni/Co_3O_4 was developed so as to save the d.c.electric energy over 160 kWh/t of Sb.展开更多
This paper describes the effect of the composition of the oxide films on the properties of electrodes Ti/M<sub>x</sub>Ti<sub>y</sub>Sn<sub>z</sub>O<sub>2</sub> (M = Ir o...This paper describes the effect of the composition of the oxide films on the properties of electrodes Ti/M<sub>x</sub>Ti<sub>y</sub>Sn<sub>z</sub>O<sub>2</sub> (M = Ir or Ru) prepared by the polymeric precursor method. XRD studies showed that the anodes are formed by solid solutions. The electrodes containing IrO<sub>2</sub> exhibit lower activity for the oxygen evolution reaction. The doping of the electrode surface with SnO<sub>2</sub> improves the catalytic properties of the anodes. However, it should be held in appropriate compositions, because the change in the atomic ratio of this element shows a marked effect on the stability of the oxides. Electrode Ti/Ir<sub>0.2</sub>Ti<sub>0.3</sub>Sn<sub>0.5</sub>O<sub>2</sub> has lower lifetime, i.e. 6 hours. The 20% decrease in the stoichiometric amount of SnO<sub>2</sub> increases the time to a value above 70 hours, as observed for Ti/Ir<sub>0.3</sub>Ti<sub>0.4</sub>Sn<sub>0.3</sub>O<sub>2</sub>. Electrode Ti/Ru<sub>0.3</sub>Ti<sub>0.4</sub>Sn<sub>0.3</sub>O<sub>2</sub> shows lifetime of 11 hours;therefore IrO<sub>2</sub> is more stable than RuO<sub>2</sub> under the conditions investigated. These results suggest that electrode Ti/Ir<sub>0.3</sub>Ti<sub>0.4</sub>Sn<sub>0.3</sub>O<sub>2</sub> is promising for different applications, such as water electrolysis, capacitors and organic electrosynthesis.展开更多
Chlorine(Cl2)is one of the most important chemicals produced by the electrolysis of brine solutions and is a key raw material for many areas of industrial chemistry.For nearly half a century,dimensionally stable anode...Chlorine(Cl2)is one of the most important chemicals produced by the electrolysis of brine solutions and is a key raw material for many areas of industrial chemistry.For nearly half a century,dimensionally stable anode(DSA)made from a mixture of RuO_(2) and TiO_(2) solid oxides coated on Ti substrate has been the most widely used electrode for chlorine evolution reaction(CER).In harsh operating environments,the stability of DSAs remains a major challenge greatly affecting their lifetime.The deactivation of DSAs significantly increases the cost of the chlor-alkali industry due to the corrosion of Ru and the formation of the passivation layer TiO_(2).Therefore,it is urgent to develop catalysts with higher activity and stability,which requires a thorough understanding of the deactivation mechanism of DSA catalysts.This paper reviews existing references on the deactivation mechanisms of DSA catalysts,including both experimental and theoretical studies.Studies on how CER selectivity affects electrode stability are also discussed.Furthermore,studies on the effects of the preparation process,elemental composition,and surface/interface structures on the DSA stability and corresponding improvement strategies are summarized.The development of other non-DSA-type catalysts with comparable stability is also reviewed,and future opportunities in this exciting field are also outlined.展开更多
文摘The anode reaction and current density of the electrowinning of Sb from jamesonite concen- trate have been investigate.High anodic current density seems to be the major reason for high energy consumption,air pollution by alkaline mists in workshop as well as poor quality of deposition.A series of steps,such as absorption,phase formation,ageing of passivated films etc.,were found to be involved during the anodic passivating process of Fe in NaOH solution. A new anodic material Fe/Ni/Co_3O_4 was developed so as to save the d.c.electric energy over 160 kWh/t of Sb.
文摘This paper describes the effect of the composition of the oxide films on the properties of electrodes Ti/M<sub>x</sub>Ti<sub>y</sub>Sn<sub>z</sub>O<sub>2</sub> (M = Ir or Ru) prepared by the polymeric precursor method. XRD studies showed that the anodes are formed by solid solutions. The electrodes containing IrO<sub>2</sub> exhibit lower activity for the oxygen evolution reaction. The doping of the electrode surface with SnO<sub>2</sub> improves the catalytic properties of the anodes. However, it should be held in appropriate compositions, because the change in the atomic ratio of this element shows a marked effect on the stability of the oxides. Electrode Ti/Ir<sub>0.2</sub>Ti<sub>0.3</sub>Sn<sub>0.5</sub>O<sub>2</sub> has lower lifetime, i.e. 6 hours. The 20% decrease in the stoichiometric amount of SnO<sub>2</sub> increases the time to a value above 70 hours, as observed for Ti/Ir<sub>0.3</sub>Ti<sub>0.4</sub>Sn<sub>0.3</sub>O<sub>2</sub>. Electrode Ti/Ru<sub>0.3</sub>Ti<sub>0.4</sub>Sn<sub>0.3</sub>O<sub>2</sub> shows lifetime of 11 hours;therefore IrO<sub>2</sub> is more stable than RuO<sub>2</sub> under the conditions investigated. These results suggest that electrode Ti/Ir<sub>0.3</sub>Ti<sub>0.4</sub>Sn<sub>0.3</sub>O<sub>2</sub> is promising for different applications, such as water electrolysis, capacitors and organic electrosynthesis.
文摘Chlorine(Cl2)is one of the most important chemicals produced by the electrolysis of brine solutions and is a key raw material for many areas of industrial chemistry.For nearly half a century,dimensionally stable anode(DSA)made from a mixture of RuO_(2) and TiO_(2) solid oxides coated on Ti substrate has been the most widely used electrode for chlorine evolution reaction(CER).In harsh operating environments,the stability of DSAs remains a major challenge greatly affecting their lifetime.The deactivation of DSAs significantly increases the cost of the chlor-alkali industry due to the corrosion of Ru and the formation of the passivation layer TiO_(2).Therefore,it is urgent to develop catalysts with higher activity and stability,which requires a thorough understanding of the deactivation mechanism of DSA catalysts.This paper reviews existing references on the deactivation mechanisms of DSA catalysts,including both experimental and theoretical studies.Studies on how CER selectivity affects electrode stability are also discussed.Furthermore,studies on the effects of the preparation process,elemental composition,and surface/interface structures on the DSA stability and corresponding improvement strategies are summarized.The development of other non-DSA-type catalysts with comparable stability is also reviewed,and future opportunities in this exciting field are also outlined.
