Service life of two different oxide anodes in phenolsulfonic acid (PSA) solution was investigated by accelerated electrolysis. The durability of Ti/IrO_2+Ta_2 O_5 anode increased by the addition of SnO_2 in the mixed...Service life of two different oxide anodes in phenolsulfonic acid (PSA) solution was investigated by accelerated electrolysis. The durability of Ti/IrO_2+Ta_2 O_5 anode increased by the addition of SnO_2 in the mixed oxides. The degradation mechanisms of Ti/IrO_2+ Ta_2 O_5 and Ti/IrO_2 +Ta_2 O_5 +SnO+2 anodes were different. It was shown from the observation of scanning electron microscopy (SEM) and the electrochcmical measurement that, the deactivation of Ti/IrO_2 + Ta_2 O_5 anode was due to the build-up of an organic film on surface. The growth of the covered film on surface was restricted by addition of SnO_2, which resulted in increasing of the service life of anodes. The over-potential for oxygen evolution on Ti/IrO_2 +Ta_2 O_5 electrode increased after doping SnO_2, and the intermediate products of PSA building-up on the surface was much more rapidly oxidized. Meanwhile, a certain part of the surface oxide deposit entered into the solution leading to loss of oxides, which resulted in degradation of Ti/IroO_2 + Ta_2 O_5 anode containing SnO_2 component.展开更多
The electrosynthesis of H_(2)O_(2)as an environmentally friendly green process has attracted great attention due to the importance of H_(2)O_(2)in industry and human lives.In this work,a new strategy was proposed to i...The electrosynthesis of H_(2)O_(2)as an environmentally friendly green process has attracted great attention due to the importance of H_(2)O_(2)in industry and human lives.In this work,a new strategy was proposed to improve the electrical conductivity and H_(2)O_(2)selectivity of transition metal oxides catalysts.F-C(F doped carbon)was coupled with Ta_(2)O_(5)by calcining polyvinylidene fluoride(PVDF)as the carbon source using one step method.The Ta_(2)O_(5)/F-C composite catalysts show an excellent H_(2)O_(2)selectivity of more than 80%as well as high reactivity at 2.52 mA/cm^(2),which is greatly enhanced compared to the counterparts of F-C(selectivity of 59%)and Ta_(2)O_(5)-800(current density of 0.85 mA/cm^(2))in 0.1 M KOH solution.The onset potential for H_(2)O_(2)production on Ta_(2)O_(5)/F-C composites is 0.78 V in 0.1 M KOH,which indicates a negligible overpotential.In addition,H_(2)O_(2)selectivity of the catalyst can be stabilized at more than 80%after 10 hours of electrolysis in alkaline electrolyte.The high performance due to the introduction of F-C increases the conductivity of Ta_(2)O_(5)and the synergistic effect between F-C and Ta_(2)O_(5).This work proposed an efficient synergistic effect among F-doped C and Ta_(2)O_(5)for H_(2)O_(2)production.展开更多
The shuttle effect of polysulfides during the charging and discharging of lithium-sulfur(Li-S)batteries and the growth of Li dendrites are crucial obstacles to hinder the commercialization of Li-S batteries.Heterostru...The shuttle effect of polysulfides during the charging and discharging of lithium-sulfur(Li-S)batteries and the growth of Li dendrites are crucial obstacles to hinder the commercialization of Li-S batteries.Heterostructure engineering is an effective strategy to accelerate catalytic conversion and suppress the dissolution of polysulfides.Herein,we report a Ta_(4)C_(3)-Ta_(2)O_(5) heterostructure composite as a bi-functional modified separator that not only achieves effective protection for lithium metal but also accelerates the polysulfides redox kinetics process.This heterostructure possesses efficient chemical anchoring and abundant active sites to immobilize polysulfides by synergistic effect,which endows a stable long cycling performance for Li-S batteries.This corresponds to an initial high capacity of 801.9 mAh g^(–1) at 1 C with a decay rate of 0.086%for 500 cycles.Due to its high Young’s modulus(up to 384 GPa),Ta_(4)C_(3) contributes to forming a protective layer on the Li metal surface to inhibit the growth of Li dendrites.Accordingly,the symmetrical cell has a stable overpotential for 700 cycles at 20 mA cm^(–2)/20 mAh cm^(–2).So,this“one stone two birds”design affords a novel perspective for high-energy Li-S battery storage system design and Li metal protection.展开更多
文摘Service life of two different oxide anodes in phenolsulfonic acid (PSA) solution was investigated by accelerated electrolysis. The durability of Ti/IrO_2+Ta_2 O_5 anode increased by the addition of SnO_2 in the mixed oxides. The degradation mechanisms of Ti/IrO_2+ Ta_2 O_5 and Ti/IrO_2 +Ta_2 O_5 +SnO+2 anodes were different. It was shown from the observation of scanning electron microscopy (SEM) and the electrochcmical measurement that, the deactivation of Ti/IrO_2 + Ta_2 O_5 anode was due to the build-up of an organic film on surface. The growth of the covered film on surface was restricted by addition of SnO_2, which resulted in increasing of the service life of anodes. The over-potential for oxygen evolution on Ti/IrO_2 +Ta_2 O_5 electrode increased after doping SnO_2, and the intermediate products of PSA building-up on the surface was much more rapidly oxidized. Meanwhile, a certain part of the surface oxide deposit entered into the solution leading to loss of oxides, which resulted in degradation of Ti/IroO_2 + Ta_2 O_5 anode containing SnO_2 component.
基金supported by the National Natural Science Foundation of China(No.21703248)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB20000000)。
文摘The electrosynthesis of H_(2)O_(2)as an environmentally friendly green process has attracted great attention due to the importance of H_(2)O_(2)in industry and human lives.In this work,a new strategy was proposed to improve the electrical conductivity and H_(2)O_(2)selectivity of transition metal oxides catalysts.F-C(F doped carbon)was coupled with Ta_(2)O_(5)by calcining polyvinylidene fluoride(PVDF)as the carbon source using one step method.The Ta_(2)O_(5)/F-C composite catalysts show an excellent H_(2)O_(2)selectivity of more than 80%as well as high reactivity at 2.52 mA/cm^(2),which is greatly enhanced compared to the counterparts of F-C(selectivity of 59%)and Ta_(2)O_(5)-800(current density of 0.85 mA/cm^(2))in 0.1 M KOH solution.The onset potential for H_(2)O_(2)production on Ta_(2)O_(5)/F-C composites is 0.78 V in 0.1 M KOH,which indicates a negligible overpotential.In addition,H_(2)O_(2)selectivity of the catalyst can be stabilized at more than 80%after 10 hours of electrolysis in alkaline electrolyte.The high performance due to the introduction of F-C increases the conductivity of Ta_(2)O_(5)and the synergistic effect between F-C and Ta_(2)O_(5).This work proposed an efficient synergistic effect among F-doped C and Ta_(2)O_(5)for H_(2)O_(2)production.
基金supported by the National Natural Science Foundation of China(Nos.52202104,51875330,51975342)the China Postdoctoral Science Foundation(Nos.2021T140433,2020M683408)+1 种基金the Natural Science Foundation of Shaanxi Province(Nos.2019JZ-24,2021JQ-538)the Natural Science Foundation of Zhejiang Province(LZY23B030002).
文摘The shuttle effect of polysulfides during the charging and discharging of lithium-sulfur(Li-S)batteries and the growth of Li dendrites are crucial obstacles to hinder the commercialization of Li-S batteries.Heterostructure engineering is an effective strategy to accelerate catalytic conversion and suppress the dissolution of polysulfides.Herein,we report a Ta_(4)C_(3)-Ta_(2)O_(5) heterostructure composite as a bi-functional modified separator that not only achieves effective protection for lithium metal but also accelerates the polysulfides redox kinetics process.This heterostructure possesses efficient chemical anchoring and abundant active sites to immobilize polysulfides by synergistic effect,which endows a stable long cycling performance for Li-S batteries.This corresponds to an initial high capacity of 801.9 mAh g^(–1) at 1 C with a decay rate of 0.086%for 500 cycles.Due to its high Young’s modulus(up to 384 GPa),Ta_(4)C_(3) contributes to forming a protective layer on the Li metal surface to inhibit the growth of Li dendrites.Accordingly,the symmetrical cell has a stable overpotential for 700 cycles at 20 mA cm^(–2)/20 mAh cm^(–2).So,this“one stone two birds”design affords a novel perspective for high-energy Li-S battery storage system design and Li metal protection.
