4. Experimental sections
Sodium molybdate dihydrate
(Na2MoO4∙2H2O, 99.5%
purity; Sigma aldrich), selenium powder (Se, 99.5% purity, Sigma
aldrich), sodium borohydride (NaBH4, 97% purtiy;
Daejung), and ethanol (C2H5OH, 99.5%
purity; Daejung) were used without purification. Deionized (DI) water of
18.2 MΩ cm−1 was obtained using a water purification
system (V-RO up 15-S, A.F ENG, Korea).