The functionalization of multi-walled carbon nanotubes （MWCNTs） by ozone treatment has been sys- tematically investigated by using Raman spectroscopy, transmission electron microscopy （TEM）, Fourier transform inha...The functionalization of multi-walled carbon nanotubes （MWCNTs） by ozone treatment has been sys- tematically investigated by using Raman spectroscopy, transmission electron microscopy （TEM）, Fourier transform inhared spectroscopy （FTIR）, X-ray photoelectron spectroscopy （XPS）, organic elemental anal- ysis （OEA） and Boehm titration. The results showed that the functionalization process occurred at defective sites （opened mouths, tube caps, debris, etc.） before opening caps and truncating walls, and finally the graphitic structure was deteriorated. The surface oxygen content first increased with the treatment time but kept at around 8.0 wt% after 5 h. The analysis of the distribution of oxygen-containing groups re- vealed that phenolic hydroxyl was gradually converted to carboxyl and lactone, The carboxyl was found to play a pivotal role to reduce the over-potentials when we used the functionalized MWCNTs as the cat- alyst for oxygen reduction reaction （ORR）.展开更多
The carbon nanotubes(CNTs) as the emerging materials for organic pollutant removal have gradually become a burgeoning research field.Herein,a mini-review of CNTs-based materials curre ntly studies for organic pollutan...The carbon nanotubes(CNTs) as the emerging materials for organic pollutant removal have gradually become a burgeoning research field.Herein,a mini-review of CNTs-based materials curre ntly studies for organic pollutant elimination is presented.This review summarizes the preparation methods of CNTsbased materials.CNTs-based materials can be used as adsorbents to remove organic pollutants in wastewater.The adsorption mechanisms mainly include surface diffusio n,pore diffusion and adsorption reaction.Most importantly,an in-depth overview of CNTs-based materials currently available in advanced oxidation processes(AOPs) applications for wastewater treatment is proposed.CNTs-based materials can catalyze different oxidants(e.g.,hydrogen peroxide(H2 O2),persulfates(PMS/PDS),ozone(O3) and ferrate/permanganate(Fe(Ⅵ)/Mn(Ⅶ)) to generate more reactive oxygen species(ROS) for organic pollutant elimination.Moreover,the possible reaction mechanisms of removing organic pollutants by CNTs-based materials are summarized systematically and discussed in detail.Finally,application potential and future research directions of CNTs-based materials in the environmental remediation field are proposed.展开更多
Electrocatalytic oxygen evolution reaction(OER)is one of the crucial reactions for converting renewable electricity into chemical fuel in the form of hydrogen.To date,there is still a challenge in designing ideal cost...Electrocatalytic oxygen evolution reaction(OER)is one of the crucial reactions for converting renewable electricity into chemical fuel in the form of hydrogen.To date,there is still a challenge in designing ideal cost-effective OER catalysts with excellent activity and robust durability.The hybridization of transition metal oxides and carbonaceous materials is one of the most effective and promising strategies to develop high-performance electrocatalysts.Herein,this work synthesized hybrids of NiFe_2 O_4 spinel materials with two-dimensional(2D)graphene oxide and one-dimensional(1 D)carbon nanotubes using a facile solvothermal approach.Electrocatalytic activities of NiFe_(2)O_(4) with 2 D graphene oxide toward OER were realized to be superior even to the 1 D carbon nanotube-based electro catalyst in terms of overpotential to reach a current density of10 mA/cm^(2) as well as Tafel slopes.The NiFe_(2)O_(4) with 2 D graphene oxide hybrid exhibits good stability with an overpotential of 327 mV at a current density of 10 mA/cm^(2) and a Tafel slope of 103 mV/dec.The high performance of NiFe_(2)O_(4) with 2 D graphene oxide is mainly attributed to its unique morphology,more exposed active sites,and a porous structure with a high surface area.Thus,an approach of hybridizing a metal oxide with a carbonaceous material offers an attractive platform for developing an efficient electrocatalyst for water electrochemistry applications.展开更多
燃料电池阴极氧还原反应(ORR)的电子转移过程比较复杂,反应动力学缓滞,需要高效的电催化剂来加快反应速率。传统的贵金属铂基催化剂价格昂贵,因此亟需开发高性能、低成本的非贵金属催化剂作为替代材料。首先通过溶胶凝胶和热处理,得到...燃料电池阴极氧还原反应(ORR)的电子转移过程比较复杂,反应动力学缓滞,需要高效的电催化剂来加快反应速率。传统的贵金属铂基催化剂价格昂贵,因此亟需开发高性能、低成本的非贵金属催化剂作为替代材料。首先通过溶胶凝胶和热处理,得到了尺寸约为10 nm的氧化铈/镍复合纳米颗粒,然后通过催化甲烷热分解,得到了碳纳米管支撑的氧化铈/镍纳米材料。由于碳纳米管的形成,使催化剂与电解液的接触面积增加,并且改变了金属镍的电子结构,从而使其在碱性溶液中表现出较好的电催化氧还原活性,其循环伏安的氧还原峰电位约在-0.17 V和-0.51 V左右,氧还原极化曲线的开启电位约在-0.05 V vs. SCE。展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21307142 and 21403261)Ningbo Science and Technology Bureau(No.2014D10004)
文摘The functionalization of multi-walled carbon nanotubes （MWCNTs） by ozone treatment has been sys- tematically investigated by using Raman spectroscopy, transmission electron microscopy （TEM）, Fourier transform inhared spectroscopy （FTIR）, X-ray photoelectron spectroscopy （XPS）, organic elemental anal- ysis （OEA） and Boehm titration. The results showed that the functionalization process occurred at defective sites （opened mouths, tube caps, debris, etc.） before opening caps and truncating walls, and finally the graphitic structure was deteriorated. The surface oxygen content first increased with the treatment time but kept at around 8.0 wt% after 5 h. The analysis of the distribution of oxygen-containing groups re- vealed that phenolic hydroxyl was gradually converted to carboxyl and lactone, The carboxyl was found to play a pivotal role to reduce the over-potentials when we used the functionalized MWCNTs as the cat- alyst for oxygen reduction reaction （ORR）.
基金The authors would like to acknowledge the financial support from the National Natural Science Foundation of China(No.51878423)Fundamental Research Funds for the Central Universities(No.2018SCUH0071)Excellent Youth Foundation of Sichuan Scientific Committee(No.2019JDJQ0005).
文摘The carbon nanotubes(CNTs) as the emerging materials for organic pollutant removal have gradually become a burgeoning research field.Herein,a mini-review of CNTs-based materials curre ntly studies for organic pollutant elimination is presented.This review summarizes the preparation methods of CNTsbased materials.CNTs-based materials can be used as adsorbents to remove organic pollutants in wastewater.The adsorption mechanisms mainly include surface diffusio n,pore diffusion and adsorption reaction.Most importantly,an in-depth overview of CNTs-based materials currently available in advanced oxidation processes(AOPs) applications for wastewater treatment is proposed.CNTs-based materials can catalyze different oxidants(e.g.,hydrogen peroxide(H2 O2),persulfates(PMS/PDS),ozone(O3) and ferrate/permanganate(Fe(Ⅵ)/Mn(Ⅶ)) to generate more reactive oxygen species(ROS) for organic pollutant elimination.Moreover,the possible reaction mechanisms of removing organic pollutants by CNTs-based materials are summarized systematically and discussed in detail.Finally,application potential and future research directions of CNTs-based materials in the environmental remediation field are proposed.
基金financial support from the SERB Early Career Research Project(No.ECR/2017/001850)Department of Science and Technology(Nos.DST/NM/NT/2019/205(G),DST/TDT/SHRI-34/2018)+2 种基金Karnataka Science and Technology Promotion Society(KSTePS/VGST-RGSF/2018-19/GRD NO.829/315)start-up grant,Jain University(11(39)/17/013/2017SG)Nanomission(SR/NM/NS-20/2014)for the characterization facilities。
文摘Electrocatalytic oxygen evolution reaction(OER)is one of the crucial reactions for converting renewable electricity into chemical fuel in the form of hydrogen.To date,there is still a challenge in designing ideal cost-effective OER catalysts with excellent activity and robust durability.The hybridization of transition metal oxides and carbonaceous materials is one of the most effective and promising strategies to develop high-performance electrocatalysts.Herein,this work synthesized hybrids of NiFe_2 O_4 spinel materials with two-dimensional(2D)graphene oxide and one-dimensional(1 D)carbon nanotubes using a facile solvothermal approach.Electrocatalytic activities of NiFe_(2)O_(4) with 2 D graphene oxide toward OER were realized to be superior even to the 1 D carbon nanotube-based electro catalyst in terms of overpotential to reach a current density of10 mA/cm^(2) as well as Tafel slopes.The NiFe_(2)O_(4) with 2 D graphene oxide hybrid exhibits good stability with an overpotential of 327 mV at a current density of 10 mA/cm^(2) and a Tafel slope of 103 mV/dec.The high performance of NiFe_(2)O_(4) with 2 D graphene oxide is mainly attributed to its unique morphology,more exposed active sites,and a porous structure with a high surface area.Thus,an approach of hybridizing a metal oxide with a carbonaceous material offers an attractive platform for developing an efficient electrocatalyst for water electrochemistry applications.
文摘燃料电池阴极氧还原反应(ORR)的电子转移过程比较复杂,反应动力学缓滞,需要高效的电催化剂来加快反应速率。传统的贵金属铂基催化剂价格昂贵,因此亟需开发高性能、低成本的非贵金属催化剂作为替代材料。首先通过溶胶凝胶和热处理,得到了尺寸约为10 nm的氧化铈/镍复合纳米颗粒,然后通过催化甲烷热分解,得到了碳纳米管支撑的氧化铈/镍纳米材料。由于碳纳米管的形成,使催化剂与电解液的接触面积增加,并且改变了金属镍的电子结构,从而使其在碱性溶液中表现出较好的电催化氧还原活性,其循环伏安的氧还原峰电位约在-0.17 V和-0.51 V左右,氧还原极化曲线的开启电位约在-0.05 V vs. SCE。
基金supported by the National Natural Science Foundation of China(21576299,21576300)Guangzhou Science and Technology Project(201607010104,201707010079)+3 种基金Science and Technology Planning Project of Guangdong Province(2017A050501009)the National Key Research and Development Program of China(2016YFB0101204)Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(2016TQ03N322)the fundamental Research Funds for Central Universities(17lgzd14)~~
