摘要
Electrochemical study of {Fe(NO) 2 } 10 DNIC [(2-AMP)Fe(NO) 2 ] (1) (2-AMP = 2-aminomethylpyridine) in CH 3 CN/Na 2 SO 4 aqueous solution (1 M) revealing reversible one-electron redox couples implicated that DNIC 1 may facilitate versatile chemical reactions associated with two-electron HER (hydrogen evolution reaction) processes. The three-component photocatalytic HER system is composed of MeOH-H 2 O solution (1:1 volume ratio, pH = 11.0) of molecular catalyst DNIC 1 (1.6 μM), photosensitizer fluorescein (Fl) (1.5 mM) and sacrificial electron donor triethylamine (0.36 M) was developed. The reductive quenching rate (R 1 ) (electron transfer from Et 3 N to Fl) and the oxidative quenching rate (R 2 ) (electron transfer from [Fl] − to DNIC 1) were calculated as 2.11 × 10 7 s −1 and 3.984 × 10 4 s −1 , respectively. The faster electron transfer from [Fl] − to DNIC 1, compared to the electron-transfer rate (R 3 ) from [DNIC 1] − to H 2 O, rationalized the accumulation of the transient-stable [DNIC 1] − , degrading to [DNIC 1] − -transformed photocatalytic active particles (Fe 3 O 4 [major]). The three-component photocatalytic system composed of MeOH-H 2 O solution of the isolated particles (2 mg), Fl (1.5 mM), and Et 3 N (0.36 M) was also employed for photocatalytic HER reaching TON 13456 μmol H2 /g catalyst , TOF 2691 hr −1 μmol H2 /g catalyst and the apparent quantum yield 3.71% under radiation (480 nm). That is, for the photocatalytic HER device constructed via a combination of DNIC 1, Fluorescein, and triethylamine, both the homogeneous catalytic HER triggered by {Fe(NO) 2 } 10 -reduced [DNIC 1] − and the heterogeneous catalytic HER promoted by [DNIC 1] − -transformed particles operated concomitantly to drive this photocatalytic HER.