Co_3O_4/Au超薄片电子态调控及电化学析氧性能研究
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摘要
通过溶剂热法以及后续热处理得到2. 6 nm厚的超薄多孔Co_3O_4纳米片,这种超薄多孔结构可为反应提供更多的活性位点。并且通过简单的浸渍法在纳米片表面负载金颗粒,对纳米片进行金修饰实现对Co~(2+)/Co~(3+)的价态比例调控,其中Co~(2+)更利于提高电催化析氧活性。结果表明,相比于未负载的Co_3O_4纳米片,金负载量为7%的Co_3O_4/Au样品析氧性能提高20%以上,并展示出更好的稳定性。
Ultrathin porous Co_3O_4 nanosheets with a thickness of 2.6 nm are synthesized through solvothermal process and subsequent heat treatment.Such ultrathin porous structure can provide more active sites for the reaction.Gold particles are loaded onto the surface of the nanosheet by a simple impregnation method afterwards.XPS results reveal that noble metal Au deposition can adjust the ratio of Co~(2+)/Co~(3+),and Co~(2+)is more conducive to improve the oxygen evolution activity.Compared with the pure Co_3O_4 nanosheets,the oxygen evolution performance of Co_3O_4/Au catalyst with 7 wt%gold loadings is more than 20 percent enhanced,in addition with much better stability.
Ultrathin porous Co_3O_4 nanosheets with a thickness of 2.6 nm are synthesized through solvothermal process and subsequent heat treatment.Such ultrathin porous structure can provide more active sites for the reaction.Gold particles are loaded onto the surface of the nanosheet by a simple impregnation method afterwards.XPS results reveal that noble metal Au deposition can adjust the ratio of Co~(2+)/Co~(3+),and Co~(2+)is more conducive to improve the oxygen evolution activity.Compared with the pure Co_3O_4 nanosheets,the oxygen evolution performance of Co_3O_4/Au catalyst with 7 wt%gold loadings is more than 20 percent enhanced,in addition with much better stability.
引文
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[2]Lim B,Jiang M,Camrgo P H,et al.Pd-Pt bimetallic nanodendrites with high activity for oxygen reduction[J]. Science,2009,324(5932):1302-1305.
[3]Bao J,Zhang X,Fan B,et al.Ultrathin spinel-structured nanosheets rich in oxygen deficiencies for enhanced electrocatalytic water oxidation[J].Angew Chem Int Ed Engl,2015,54(25):7399-7404.
[4]Song F,Hu X.Exfoliation of layered double hydroxides for enhanced oxygen evolution catalysis[J].Nat Commun,2014,5:4477-.
[5]Song F,Hu X.Ultrathin cobalt-manganese layered double hydroxide is an efficient oxygen evolution catalyst[J].J Am Chem Soc,2014,136(47):16481-16484.
[6]Tüysüz H,Hwang Y J,Khan S B,et al.Mesoporous Co3O4as an electrocatalyst for water oxidation[J].Nano Research,2012,6(1):47-54.
[7]Liang L,Lei F,Gao S,et al.Single unit cell bismuth tungstate layers realizing robust solar CO2reduction to methanol[J]. Angew Chem Int Ed Engl,2015,54(47):13971-13974.
[8]Qu Q,Zhang J H,Wang J,et al.Three-dimensional ordered mesoporous Co3O4enhanced by Pd for oxygen evolution reaction[J].Sci Rep,2017,7:41542.
[9]Wu J,Xue Y,Yan X,et al. Co3O4nanocrystals on single-walled carbon nanotubes as a highly efficient oxygen-evolving catalyst[J].Nano Research,2012,5(8):521-530.
[10]Zhang J J,Wang H H,Zhao T J,et al.Oxygen vacancy engineering of Co3O4nanocrystals through coupling with metal support for water oxidation[J].ChemSusChem,2017,10(14):2875-2879.
[11]Dou Y,Liao T,Ma Z,et al.Graphene-like holey Co3O4nanosheets as a highly efficient catalyst for oxygen evolution reaction[J].Nano Energy,2016,30:267-275.
[12]Lu X,Zhao C. Electrodeposition of hierarchically structured threedimensional nickel-iron electrodes for efficient oxygen evolution at high current densities[J].Nat Commun,2015,6:6616.
[13]Chen Y,Hu J,Diao H,et al.Facile preparation of ultrathin Co3O4/nanocarbon composites with greatly improved surface activity as a highly efficient oxygen evolution reaction catalyst[J]. Chemistry,2017,23(16):4010-4016.
[14]Wang W,Kuai L,Cao W,et al.Mass-production of mesoporous MnCo2O4spinels with manganese(Ⅳ)-and cobalt(Ⅱ)-rich surfaces for superior bifunctional oxygen electrocatalysis[J]. Angew Chem Int Ed Engl,2017,56(47):14977-14981.
[15]Xu L,Jiang Q,Xiao Z,et al. Plasma-engraved Co3O4nanosheets with oxygen vacancies and high surface area for the oxygen evolution reaction[J]. Angew Chem Int Ed Engl,2016,55(17):5277-5281.
[16]Wang H Y,Huang S F,Chen H Y,et al.In operando identification of geometrical-site-dependent water oxidation activity of spinel Co3O4[J].J Am Chem Soc,2016,138(1):36-39.