Application of First-principle Calculation to Development of Water Electrolysis Anode Catalyst. Kenji Toyoda. Reiko Hinogami.

Transcription

1 Application of First-principle Calculation to Development of Water Electrolysis Anode Catalyst Reiko Hinogami Kenji Toyoda Nobuhiro Miyata ABO 2 A=B = Be g The design of a cost-effective and highly active anode catalyst for water electrolysis is a critical challenge to achieve a hydrogen economy. Delafossite oxides (ABO 2 ; A=Cu or Ag, B = transition metal) were investigated for their potential as oxygen-evolution reaction catalysts using a first-principle calculation. From the investigation of copper delafossite oxides, it was confirmed that there is a strong correlation between the electrochemical catalytic activity (onset potential) and the electronic state at the B site (e g electron occupancy) which was estimated using bulk density-functional theory calculations. From this finding, we predicted the catalytic activity of silver delafossite oxide and found a highly active catalyst composition. This paper also introduces an examination of the reaction mechanism, case study on the surface electronic structure calculation and device application examples V Oxygen Evolution ReactionOER 1.8 V OERNiCo [1], [2] Schematic figure of electrolyzer OER p OER1980PtPd

2 90 [3]Cu Ag OER ABO 2 A 1B3B Bd t 2g e g OER [4]-[6] e g [7]e g e g e g X[7] e g (a)(b)b (a) Structure of delafossite and (b) electronic structure of B site [8]-[13] CuAlO 2 CuFeO 2 CuCrO 2 CuRhO 2 Cu 2 OBB 2 O [8], [11], [13] CuCoO 2 AgAlO 2 AgFeO 2 AgCoO 2 CuCoAg [9], [12], [13]Cu 2 O Ag 2 OB 2 O 3 CoOOH Teflon 1 NaOH150 AgAlO 2 AgFeO 2 AgCoO 2 Ag 2 O 10 % CuCoO 2 CuO CuO AgRhO 2 LiRhO 2 AgNO 3 KNO [10] XX Ray DiffractionXRD 3R N 2 Brunauer, Emmett, Teller BET XRD Powder XRD patterns of synthesized delafossites OERRDE CV 1The Chemours Company FC, LLC.

3 91 Nafion 2 1 M KOHPt RHE2000 rpm 50 mv/s Density Functional TheoryDFTSTATE [14] 25 Ry Ry GGA-PBE B-Oc Bd e g t 2g Bd Partial Density of StatesPDOSe g 3R [13] ACu CV ir BET CV CuCV Cyclic Voltammetry (CV) characteristics of Cu delafossites 2The Chemours Company FC, LLC. 3 1Ry=13.6eV CVB CuCoO 2 CuRhO 2 OER DFT e g 50 μa/cm 2 e g Cu [3]ABO 2 ABCu e g e g =2.0 Volcano A Be g OER [11], [13] OER eg Correlation of OER catalytic activity and eg electron occupancy of Cu and precious metal delafossites 4.1Ae g 2.0 OER AAg Ag DFTe g e g =2.0AgCoO 2 AgRhO 2 AgAe g e g electron occupancy of Ag delafossites

4 92 AgOER CVDFT AgCoO 2 AgRhO 2 e g DFTOER [12] AgCV Cyclic Voltammetry (CV) characteristics of Ag delafossites OERe g OEROH [7]step2H + step3oh - DFT [6], [15]step2step3 OH + OH - M-O DFT M-O OOH - step3 M-Ostep2 OER Proposed OER mechanism on transition-metal oxide catalysts M-Oe g e g M-O e g M-O step3m-o step2 e g 4e g =2.0 e g DFT CuCoO 2 BPDOS 1st layer E F d dt 2g [001](001)t 2g E F t 2g E F t 2g [13] CuCoO 2 Co-dPDOS PDOS of Co-d states in the CuCoO 2 [ev] The number of states per unit energy [ev] in unit cell

5 93 e g t 2g ae g bt 2g OER e g volcano t 2g OER volcano e g OER ae g bt 2g Correlation of OER catalytic activity and electronic state of delafossites; (a) e g electron occupancy, (b) t 2g electron occupancy nafion AgCoO 2 IrO 2 [16] OER DFT DFTe g.dft t 2g e g t 2g e g volcanoe g e g =2.0 STATE [1] D. Pletcher et al., Prospects for alkaline zero gap water electrolysers for hydrogen production, Int. J. Hydrogen Energy, vol. 36, issue 23, pp , [2] M. Carmo et al., A comprehensive review on PEM water electrolysis, International J. Hydrogen Energy, vol. 38, issue 12, pp , [3] P. F. Carcia et al., O 2 electrocatalysis on thin film metallic oxide electrodes with the delafossite structure, J. Electrochem. Soc., vol. 127, issue 9, pp , [4] S. Trasatti, Electrocatalysis in the anodic evolution of oxygen and chlorine, Electrochim. Acta, vol. 29, issue 11, pp , [5] J.O. Bockris et al., The electrocatalysis of oxygen evolution on perovskites, J. Electrochem. Soc. vol. 131, issue 2, pp , [6] I. C. Man et al., Universality in oxygen evolution electrocatalysis on oxide surfaces, ChemCatChem, vol. 3, issue 7, pp , [7] J. Suntivich et al., A Perovskite Oxide Optimized for Oxygen Evolution Catalysis from Molecular Orbital Principles, Science,

6 94 vol. 334, issue 6061, pp , [8] M. Marquardt et al., Crystal Chemistry and Electrical Properties of the Delafossite Structure, Thin Solid Films, vol. 496, issue 1, pp , [9] W. C. Sheets et al., Hydrothermal synthesis of delafossite-type oxides, Chem. Mater., vol. 18, issue 1, pp.7 20, [10] V. Todorova et al., On AgRhO 2, and the new quaternary delafossites AgLi 1/3 M 2/3 O 2, syntheses and analyses of real structures, J. Solid State Chemistry, vol. 184, issue 5, pp , [11] R. Hinogami et al., Active copper delafossite anode for oxygen evolution reaction, Electrochemistry Communications, vol. 35, pp , Oct [12] "," 20141E07Sep [13] K. Toyoda et al., Calculated descriptors of catalytic activity for water electrolysis anode: Application to delafossite oxides, J. Phys. Chem. C, vol. 119, issue 12, pp , [14] Y. Morikawa et al., Density-Functional Analysis of Hydrogen on Pt(111): Electric Field, Solvent, and Coverage Effects, J. Phys. Chem. C, vol. 112, issue 29, pp , [15] J. Rossmeisl et al., Electrolysis of water on oxide surfaces, J. Electroanal. Chem., vol. 607, issue 1-2, pp , [16] "AgCoO 2," 20152G08Sep Hydrogen And Energy Research Lab., Advanced Research Div. Hydrogen And Energy Research Lab., Advanced Research Div. Hydrogen And Energy Research Lab., Advanced Research Div.