TY - JOUR

T1 - The decomposition of mixed oxide Ag2Cu2O3

T2 - Structural features and the catalytic properties in CO and C2H4 oxidation

AU - Svintsitskiy, Dmitry A.

AU - Kardash, Tatyana Yu

AU - Slavinskaya, Elena M.

AU - Stonkus, Olga A.

AU - Koscheev, Sergei V.

AU - Boronin, Andrei I.

PY - 2018/1/1

Y1 - 2018/1/1

N2 - The mixed silver-copper oxide Ag2Cu2O3 with a paramelaconite crystal structure is a promising material for catalytic applications. The as-prepared sample of Ag2Cu2O3 consisted of brick-like particles extended along the [001] direction. A combination of physicochemical techniques such as TEM, XPS and XRD was applied to investigate the structural features of this mixed silver-copper oxide. The thermal stability of Ag2Cu2O3 was investigated using in situ XRD under different reaction conditions, including a catalytic CO + O2 mixture. The first step of Ag2Cu2O3 decomposition was accompanied by the appearance of ensembles consisting of silver nanoparticles with sizes of 5–15 nm. Silver nanoparticles were strongly oriented to each other and to the surface of the initial Ag2Cu2O3 bricks. Based on the XRD data, it was shown that the release of silver occurred along the a and b axes of the paramelaconite structure. Partial decomposition of Ag2Cu2O3 accompanied by the formation of silver nanoparticles was observed during prolonged air storage under ambient conditions. The high reactivity is discussed as a reason for spontaneous decomposition during Ag2Cu2O3 storage. The full decomposition of the mixed oxide into metallic silver and copper (II) oxide took place at temperatures higher than 300 °C regardless of the nature of the reaction medium (helium, air, CO + O2). Catalytic properties of partially and fully decomposed samples of mixed silver-copper oxide were measured in low-temperature CO oxidation and C2H4 epoxidation reactions.

AB - The mixed silver-copper oxide Ag2Cu2O3 with a paramelaconite crystal structure is a promising material for catalytic applications. The as-prepared sample of Ag2Cu2O3 consisted of brick-like particles extended along the [001] direction. A combination of physicochemical techniques such as TEM, XPS and XRD was applied to investigate the structural features of this mixed silver-copper oxide. The thermal stability of Ag2Cu2O3 was investigated using in situ XRD under different reaction conditions, including a catalytic CO + O2 mixture. The first step of Ag2Cu2O3 decomposition was accompanied by the appearance of ensembles consisting of silver nanoparticles with sizes of 5–15 nm. Silver nanoparticles were strongly oriented to each other and to the surface of the initial Ag2Cu2O3 bricks. Based on the XRD data, it was shown that the release of silver occurred along the a and b axes of the paramelaconite structure. Partial decomposition of Ag2Cu2O3 accompanied by the formation of silver nanoparticles was observed during prolonged air storage under ambient conditions. The high reactivity is discussed as a reason for spontaneous decomposition during Ag2Cu2O3 storage. The full decomposition of the mixed oxide into metallic silver and copper (II) oxide took place at temperatures higher than 300 °C regardless of the nature of the reaction medium (helium, air, CO + O2). Catalytic properties of partially and fully decomposed samples of mixed silver-copper oxide were measured in low-temperature CO oxidation and C2H4 epoxidation reactions.

KW - CO oxidation

KW - Ethylene epoxidation

KW - Mixed silver-copper oxide

KW - Oriented growth

KW - Paramelaconite

KW - Silver nanoparticles

KW - THERMAL-STABILITY

KW - AMBIENT-TEMPERATURE

KW - CRYSTAL

KW - PARAMELACONITE

KW - NANOPARTICLES

KW - SILVER-COPPER-OXIDE

KW - CARBON-MONOXIDE

KW - SURFACE

KW - ETHYLENE EPOXIDATION

KW - CUO

UR - http://www.scopus.com/inward/record.url?scp=85027525598&partnerID=8YFLogxK

U2 - 10.1016/j.apsusc.2017.08.010

DO - 10.1016/j.apsusc.2017.08.010

M3 - Article

AN - SCOPUS:85027525598

VL - 427

SP - 363

EP - 374

JO - Applied Surface Science

JF - Applied Surface Science

SN - 0169-4332

ER -