One-Pot Photosynthesis of Cubic Fe@Fe₃O₄ Core–Shell Nanoparticle Well-Dispersed in N-Doping Carbonaceous Polymer Using a Molecular Dinitrosyl Iron Precursor

Abstract

Nanoscale zerovalent iron (NZVI) features potential application to biomedicine, (electro-/photo)catalysis, and environmental remediation. However, multiple-synthetic steps and limited ZVI content prompt the development of a novel strategy for efficient preparation of NZVI composites. Herein, a dinitrosyl iron complex [(N 3 MDA)Fe(NO) 2 ] (1-N 3 MDA) was explored as a molecular precursor for one-pot photosynthesis of a cubic Fe@Fe 3 O 4 core−shell nanoparticle (ZVI% = 60%) well-dispersed in an N-doping carbonaceous polymer (NZVI@NC). Upon photolysis of 1-N 3 MDA, photosensitizer Eosin Y, and sacrificial reductant TEA, the α-diimine N 3 MDA and noninnocent NO ligands (1) enable the slow reduction of 1-N 3 MDA into an unstable [(N 3 MDA)Fe(NO) 2 ] − species, (2) serve as a capping reagent for controlled nucleation of zerovalent Fe atom into Fe nanoparticle, and (3) promote the polymerization of degraded Eosin Y with N 3 MDA yielding an N-doping carbonaceous matrix in NZVI@NC. This discovery of a one-pot photosynthetic process for NZVI@NC inspires continued efforts on its application to photolytic water splitting and ferroptotic chemotherapy in the near future.

Dinitrosyl Iron Complex-Derived Nanosized Zerovalent Iron (NZVI) as a Template for the Fe–Co Cracked NZVI: An Electrocatalyst for the Oxygen Evolution Reaction

“…High-resolution TEM (HRTEM) imaging revealed the core–shell structure of Fe@Fe 3 O 4 , with a shell thickness of approximately 4 nm. The HRTEM image displayed a d -spacing of 0.26 nm in the shell, corresponding to the (311) plane of the Fe 3 O 4 phase, and a d -spacing of 0.22 nm in the core, matching the (110) plane of Fe 0 (Figure d) . The TEM–selected area electron diffraction (TEM–SAED) pattern corroborated the PXRD results, showing the presence of the (110), (200), and (211) planes for the zerovalent iron phase as well as the (311) plane for Fe 3 O 4 (Figure e) .…”

“…These images revealed that the Fe@Fe 3 O 4 exhibited a cube-like shape with an average size of 80 nm and were dispersed on an organic support. Transmission electron microscopy (TEM) analysis confirmed the SEM observations and demonstrated that the Fe@Fe 3 O 4 were well dispersed on the organic support (Figure c) . High-resolution TEM (HRTEM) imaging revealed the core–shell structure of Fe@Fe 3 O 4 , with a shell thickness of approximately 4 nm.…”

“…The HRTEM image displayed a d-spacing of 0.26 nm in the shell, corresponding to the (311) plane of the Fe 3 O 4 phase, and a d-spacing of 0.22 nm in the core, matching the (110) plane of Fe 0 (Figure 1d). 35 The TEM−selected area electron diffraction (TEM−SAED) pattern corroborated the PXRD results, showing the presence of the (110), (200), and (211) planes for the zerovalent iron phase as well as the (311) plane for Fe 3 O 4 (Figure 1e). 35 To further confirm the zerovalent iron purity of the freshly prepared Fe@Fe 3 O 4 , X-ray photoelectron spectroscopy (XPS) analysis of the Fe 2p spectra was conducted at different etch depths (Figure S2).…”

“…For this reason, it is expected that the release of hydrogen gas occurs during the photosynthesis of nanosized zerovalent iron material Fe@Fe 3 O 4 . To gain insights into the role of DNIC 1-N 3 MDA in the formation of Fe@Fe 3 O 4 containing high percentage of ZVI compared to FeCl 3 as an iron precursor, 35 a comparison was made between the induction time for hydrogen evolution using DNIC 1-N 3 MDA and FeCl 3 as iron precursors. Interestingly, DNIC 1-N 3 MDA exhibited a 1 h induction time before the onset of hydrogen evolution, in contrast to FeCl 3 (Figure 1f).…”

“…35 To further confirm the zerovalent iron purity of the freshly prepared Fe@Fe 3 O 4 , X-ray photoelectron spectroscopy (XPS) analysis of the Fe 2p spectra was conducted at different etch depths (Figure S2). 35 The indicative binding energies of Fe 2p 3/2 (706.2 eV) and Fe 2p 1/2 (719.2 eV) observed in the inner layers suggested the presence of zerovalent Fe. The surface layer exhibited Fe 2+/3+ with a binding energy of 710.4 eV for Fe 2p 3/2 and 723.8 eV for Fe 2p 1/2 .…”