氧还原和氧析出是燃料电池、金属空气电池中关键的电化学反应。为了促进氧还原和氧析出反应的动力学过程,剥离制备了表面具有负电荷的氧化石墨纳米片和表面带有正电荷的钴镍纳米片层,基于静电作用通过层层自组装的方法,制备了结构有序的氧化石墨烯负载的钴镍双羟基氢氧化物纳米片层材料,并进一步通过煅烧得到了同样结构有序的具有尖晶石结构的钴镍过渡金属氧化物。通过SEM、EDS和XRD表征了所制备材料的微观结构和组成,通过电化学测试研究了所制备材料对于氧还原和氧析出反应的催化性能。结果表明,自组装制备的氧化石墨烯负载的钴镍双羟基氢氧化物纳米片具有良好的氧还原催化活性,极限电流密度和商品化的碳载铂相当,远远超过了传统的水热法合成的钴镍双羟基氢氧化物。这种催化活性的提高主要来源于自组装方法制备的材料在结构上的高度有序,钴镍双羟基氢氧化物层状结构的优势以及石墨烯的载体效应。同时,由其转变得到的具有尖晶石结构的钴镍氧化物对氧析出反应表现出较好的催化性能。
Oxygen reduction and oxygen evolution are the key electrochemical reactions in fuel cells and metal-air batteries.In order to promote the kinetic process of oxygen reduction and oxygen evolution reaction,graphite oxide(GO) nanosheets with a negative charge on the surface and cobalt-nickel nanosheets with a positive charge on the surface were exfoliate for preparing GO-supported cobalt-nickel(CoNi) layered double hydroxide nanosheet with ordered structure.Specially,the GO-supported CoNi layered double hydroxide nanosheet can transform to CoNi transition metal oxide with spinel structure at a certain condition by calcination.The microstructure and composition of the prepared materials was studied by SEM combined with EDS and XRD characterization.The catalytical performance of the prepared materials for oxygen reduction and oxygen evolution reaction was studied by electrochemical tests.The results shown that the GO-supported CoNi dihydroxy hydroxide nanosheets prepared by self-assembly had good oxygen reduction catalytic activity,and the limiting current density was comparable to the commercial carbon-supported platinum,which was far more than the corresponding material synthesized via traditional hydrothermal method.This improvement in catalytic activity was mainly due to the highly ordered structure of the materials prepared by the self-assembly method,the advantages of the layered structure of CoNi dihydroxy hydroxide,and the advantage of the GO supporter.At the same time,the CoNi oxide with spinel structure obtained from the transformation showed good catalytic performance for the oxygen evolution reaction.
[1] Shao M,Chang Q,Dodelet J P,et al.Recent advances in electrocatalysts for oxygen reduction reaction[J].Chem Rev,2016(116):3594-3657.
[2] Wang R,Xu C,Bi X,et al.Nanoporous surface alloys as highly active and durable oxygen reduction reaction electrocatalysts[J].Energy Environ Sci,2012(5):5281-5286.
[3] Abbas M A,Bang J H.Rising again:opportunities and challenges for platinum-free electrocatalysts[J].Chemistry of Materials,2015,27(21):7218-7235.
[4] Zhao Q,Yan,Chen C C,et al.Spinels:controlled preparation,oxygen reduction/evolution reaction application,and beyond[J].Chemical Reviews,2017,117(15):10121-10211.
[5] 王尧,魏子栋.过渡金属氧化物氧还原催化剂的研究进展[J].电化学,2018,24(5):427-443.
[6] Zhao J W,Shao M F,Yan D P,et al.A hierarchical heterostructure based on Pd nanoparticles/layered double hydroxide nanowalls for enhanced ethanol electrooxidation[J].Journal of Materials Chemistry A,2013,1(19):5840-5846.
[7] Abellán G,Busolo F,Coronado E,et al.Hybrid magnetic multilayers by intercalation of Cu(Ⅱ) phthalocyanine in LDH hosts[J].The Journal of Physical Chemistry C,2012,116(29):15756-15764.
[8] Liu J,Liu H,Wang F,et al.Composition-controlled synthesis of LixCo3-xO4 solid solution nanocrystals on carbon and their impact on electrocatalytic activity toward oxygen reduction reaction[J].RSC Advances,2015,5(110):90785-90796.
[9] Ma T Y,Dai S,Jaroniec M,et al.Synthesis of highly active and stable spinel-type oxygen evolution electrocatalysts by a rapid inorganic self-templating method[J].Chemistry-A European Journal,2014,20(39):12669-12676.
[10] Novoselov K S,Geim A K,Morozov S,et al.Electric field effect in atomically thin carbon films[J].Science,2004,306(5696):666-669.
[11] Tan C,Cao X,Wu X,et al.Recent advances in ultrathin two-dimensional nanomaterials[J].Chemical Reviews,2017,117(9):6225-6331.
[12] Wang H,Casalongue H S,Liang Y,et al.Ni(OH)2 nanoplates grown on graphene as advanced electrochemical pseudocapacitor materials[J].Journal of the American Chemical Society,2010,132(21):7472-7477.
[13] Pumera M.Graphene-based nanomaterials and their electrochemistry[J].Chemical Society Reviews,2010,39(11):4146.
[14] Wang H W,Hu Z A,Chang Y Q,et al.Design and synthesis of NiCo2O4-reduced graphene oxide composites for high performance supercapacitors[J].Journal of Materials Chemistry,2011,21(28):10504.
[15] Liang P J,Wang F,Hu Z A.Controlled synthesis of ordered sandwich CuCo2O4 /reduced graphene oxide composites via layer-by-layer heteroassembly for high-performance supercapacitors[J].Chemical Engineering Journal,2018,350:627-636.
[16] Ma W,Ma R,Wang C,et al.A superlattice of alternately stacked Ni-Fe hydroxide nanosheets and graphene for efficient splitting of water[J].ACS Nano,2015,9(2):1977-1984.
[17] Ku K,Kim B,Chung H,et al.Characterization of graphene-based supercapacitors fabricated on Al foils using Au or Pd thin films as interlayers[J].Synthetic Metals,2010,160(23-24),2613-2617.
[18] 徐天然.镍钴铝层状双氢氧化物/石墨烯复合材料的制备及其超电容性能研究[D].马鞍山:安徽工业大学,2017.
[19] 冯艳艳,黄宏斌,杨文,等.镍钴双金属氢氧化物/乙炔黑复合材料的制备及其电化学性能[J].化工进展,2018,37(11):4378-4383.
[20] 王海燕,石高全.层状双金属氢氧化物/石墨烯复合材料及其在电化学能量存储与转换中的应用[J].物理化学学报,2018,34(1):22-35.
