Inorganic Chemistry
Article
(
and deposition of the BSeF/Ni(OH) nanohybrids can be
2
38,11
2+
explained by a nucleation growth mechanism.
The Ni ions
and S2). The organic−inorganic nanohybrids BSeF/Ni(OH)
present in 1:1 DMSO/deionized water solution interact with
hydroxide ions accumulated on the CP for the deposition of
2
and NmocF/Ni(OH) were synthesized and deposited in situ on
2
fibrous CP using one-step reductive electrosynthesis. Reductive
electrosynthesis was carried out in an electrolytic bath of 4 mM
organic component and 40 mM Ni(NO ) ·6H O in a 1:1
Ni(OH) on the CP surface. Simultaneously, the deprotonation
2
of carboxylic acid groups of organic BSeF occurs by hydroxide
2
+
ions. The carboxylate groups of BSeF cross-link with Ni for the
formation and deposition of the Ni-BSeF nanohybrid on the CP
3
2
2
dimethyl sulfoxide (DMSO) and deionized water solution. The
three-electrode system consists of Pt wire as the counter
electrode, an Ag/AgCl electrode as the reference electrode, and
CP as the working electrode, used for the reductive electrosyn-
thesis of nanohybrids. Under a reduction potential of −0.9 V (vs
along with Ni(OH) . The simultaneous formation and
2
deposition of Ni(OH) and Ni-BSeF initiate the formation of
2
nuclei on the CP fiber surface. Under applied cathodic potential,
the nuclei grows over the CP surface to form sheet-like
nanostructures.
−
Ag/AgCl), the generation of hydroxide ions (OH ) takes place
−
35
due to reduction of water and nitrate ions (NO ) (Figure 1).
BSeF/Ni(OH) , NmocF/Ni(OH) , and Ni(OH) (Figure S3)
3
−
The generation of OH ions on the working electrode surface
increases the pH gradient near the electrode surface. The surface
2
2
2
display the characteristic diffraction pattern of bare CP without
2
+
39
accumulated hydroxide ions interact with the near-surface Ni
an additional peak. The absence of the characteristic XRD
ions through Coulombic interactions, which initiate deposition
of the metal hydroxide. Simultaneously, the carboxylic acid
groups of the respective organic component present in
electrolytic solution get deprotonated by hydroxide ions formed
at the CP surface, which results in the generation of carboxylate
ions. The carboxylate ions of the organic component strongly
bind with the Ni2+ ions present in solution through Coulombic
attractions, which results in the formation and deposition Ni-
peak of an electrodeposited nanohybrid and SAED pattern
confirms the amorphous nature of electrodeposited nanohybrids
39
and Ni(OH)2. X-ray photoelectron spectroscopy (XPS) was
used to evaluate the surface electronic state and chemical
composition of the nanohybrids. The XPS survey spectrum of
the electrodeposited BSeF/Ni(OH) nanohybrid (Figure 3a)
2
confirms the existence of nickel along with C, O, N, and Se. The
high-resolution XPS spectrum of the Ni 2p region (Figure 3b)
shows two spin−orbit doublets. The precise peaks at 855.4 and
873.1 eV with satellite peaks at 861.2 and 878.2 eV were assigned
to Ni 2p3/2 and Ni 2p1/2, respectively. The doublet peak with an
energy difference of 17.7 eV confirmed the presence of divalent
nickel ions of Ni(OH) in the BSeF/Ni(OH) nanohybrid. The
35
BSeF on the CP surface. The aromatic phenyl groups of
phenylalanine, naphthalene residue, and the benzoselenadiazole
group assist to self-assemble the organic moieties by π−π
37
stacking interactions. After 1 h of electrodeposition at a
reduction potential of −0.9 V (vs Ag/AgCl), the deposition of
2
2
∼
3 mg of BSeF/Ni(OH) nanohybrid was observed.
The morphology of nanohybrids deposited on CP was
BSeF/Ni(OH) nanohybrid shows additional deconvoluted two
2
2
spin−orbit doublet peaks in the Ni 2p region shifted to higher
binding energies. The peaks located at binding energies of 856.6
and 875.0 eV with satellite peaks at 861.9 and 880.7 eV
investigated by field emission scanning electron microscopy
FE-SEM) and high-resolution transmission electron micros-
(
2
+
copy (HR-TEM) (Figure 2). Figure 2a shows the surface of bare
confirmed the presence of Ni ions attached to carboxylate
40
carbon paper fiber. The FE-SEM image of electrodeposited
groups of BSeF. The higher binding energy of Ni-BSeF
suggests a lower electron density at the nickel center due to the
electron-withdrawing carboxylate group of BSeF. The XPS
spectrum of the C 1s (Figure 3c) region displays two peaks at
284.8 and 287.6 eV for the presence of CC and carbonyl
functional groups of the organic component, respectively. The
additional peaks at 284.4, 285.4, and 287.2 eV were attributed to
CC, CN, and carboxylate group present in the organic
BSeF/Ni(OH) after 30 min of electrodeposition at an applied
2
potential of −0.9 V vs Ag/AgCl (Figure 2b) shows the
deposition of nanosphere shaped aggregates of the nanohybrid
on the carbon paper fiber surface. The electrodeposited
nanosphere shaped aggregates accumulate on the carbon fiber
surface after 1 h of electrodeposition (Figure 2c). The high
surface area containing spherical aggregates provide increased
electrocatalytic interface for catalytic activity. The HR-TEM
41
component, respectively. The high-resolution O 1s spectrum
(Figure 3d) shows different deconvoluted O 1s peaks of
different functional groups. The deconvoluted peak at 530.2 eV
images of BSeF/Ni(OH) (Figure 2d−f) show the nonspherical
2
aggregates composed of nanosheet-like structures. These
nanosheets were cross-linked to each other, which results in
the formation of nanospheres. The amorphous nature of
nanohybrid material was confirmed by a selected area diffraction
42
was attributed to CONi bonding interactions. The
presence of CONi bonding interactions confirmed the
2
+
33
cross-linking of Ni ions with the carboxylate group of BSeF.
The peak at 531.2 eV was assigned to the CO functional
group of BSeF. The high-resolution O 1s spectrum shows peaks
at 530.76 and 531.88 eV, suggesting the presence of metal−
5
pattern. Figure S1a shows the FE-SEM image of electro-
2
28
(
oxygen bonding interactions with a Ni(OH) bond. The
morphology. The composition of cross-linked nanosheets of
deconvoluted peak at 533.0 eV suggests the presence of OH
BSeF/Ni(OH) was determined by TEM−energy-dispersive X-
bonding interaction on the BSeF/Ni(OH) nanohybrid surface.
2
2
Similar to BSeF/Ni(OH) , the XPS survey spectrum of the
2
(Figure S2) shows the presence of characteristic peaks of Ni,
NmocF/Ni(OH) (Figure 3e) nanohybrid surface shows the
2
Se, O, and N. The relative atomic percentage of Ni, O, and Se
shows the presence of 31% of Ni, 65% of O, and 3% of Se.
Furthermore, the scanning transmission electron microscopy
presence of Ni, O, C, and N. The Ni 2p region of NmocF/
Ni(OH) (Figure 3f) displays two-spin orbit doublet peaks at
2
855.5 and 872.8 eV with satellite peaks at 861.3 and 880.2 eV
(
STEM) with elemental analysis (Figure 2g−k) displays the
corresponding to Ni(OH) . The additional fitted peaks in Ni
2
uniform distribution of Ni, O, Se, and N over the cross-linked
2p3/2 and Ni 2p1/2 region with higher binding energies of 857.4
and 875.1 eV assign to Ni-NmocF. The high-resolution C 1s
nanosheets of the BSeF/Ni(OH) nanohybrid. The synthesis
2
D
Inorg. Chem. XXXX, XXX, XXX−XXX
Das, Apurba K.
