Abstract:Metallurgical
silicon was studied for photocatalytic H2 evolution activity.
It has been found that metallurgical silicon
with large particle size (above 800 nm) possesses poor photocatalytic
activity because of the deteriorating photoelectric performance of
the low-purity silicon. After size reduction (around 400 nm) and metal
nanoparticle decoration, the photocatalytic performance was significantly
enhanced to 1003.3 μmol·g–1·h–1. However, the photocatalytic performance of the Cu-,
Ag-, and Pt-decorated silic… Show more
“…Because SiNWs have a high capacity for “light absorption”, [ 7 ] high specific surface area, and higher bandgap than bulk silicon, [ 7,8 ] they meet the requirement for water splitting (to split the water molecule, 1.23 eV energy is necessary). [ 9–11 ] Despite this, there are few reports on SiNWs as a photocatalyst for direct hydrogen generation. [ 5,12–16 ] Liu et al.…”
Efficient light‐stimulated hydrogen generation from top–down produced highly doped n‐type silicon nanowires (SiNWs) with silver nanoparticles (AgNPs) in water‐containing medium under white light irradiation is reported. It is observed that SiNWs with AgNPs generate at least 2.5 times more hydrogen than SiNWs without AgNPs. The authors’ results, based on vibrational, UV–vis, and X‐ray spectroscopy studies, strongly suggest that the sidewalls of the SiNWs are covered by silicon suboxides, by up to a thickness of 120 nm, with wide bandgap semiconductor properties that are similar to those of titanium dioxide and remain stable during hydrogen evolution in a water‐containing medium for at least 3 h of irradiation. Based on synchrotron studies, it is found that the increase in the silicon bandgap is related to the energetically beneficial position of the valence band in nanostructured silicon, which renders these promising structures for efficient hydrogen generation.
“…Because SiNWs have a high capacity for “light absorption”, [ 7 ] high specific surface area, and higher bandgap than bulk silicon, [ 7,8 ] they meet the requirement for water splitting (to split the water molecule, 1.23 eV energy is necessary). [ 9–11 ] Despite this, there are few reports on SiNWs as a photocatalyst for direct hydrogen generation. [ 5,12–16 ] Liu et al.…”
Efficient light‐stimulated hydrogen generation from top–down produced highly doped n‐type silicon nanowires (SiNWs) with silver nanoparticles (AgNPs) in water‐containing medium under white light irradiation is reported. It is observed that SiNWs with AgNPs generate at least 2.5 times more hydrogen than SiNWs without AgNPs. The authors’ results, based on vibrational, UV–vis, and X‐ray spectroscopy studies, strongly suggest that the sidewalls of the SiNWs are covered by silicon suboxides, by up to a thickness of 120 nm, with wide bandgap semiconductor properties that are similar to those of titanium dioxide and remain stable during hydrogen evolution in a water‐containing medium for at least 3 h of irradiation. Based on synchrotron studies, it is found that the increase in the silicon bandgap is related to the energetically beneficial position of the valence band in nanostructured silicon, which renders these promising structures for efficient hydrogen generation.
“…In this research, Ru-modified SiNWs as electrocatalysts for hydrogen evolution reaction exhibited higher performance in comparison to the pure Ru particles. Lv et al reported that after size reduction of metallurgical silicon (particle size around 400 nm) and metal nanoparticle decoration the photocatalytic performance was significantly enhanced up to 1000 μmol·g –1 ·h –1 . Hence, the decoration of SiNWs with AgNPs is a possible way to enhance the light absorption in the visible spectral range and hydrogen generation rate.…”
Section: Introductionmentioning
confidence: 99%
“…Lv et al reported that after size reduction of metallurgical silicon (particle size around 400 nm) and metal nanoparticle decoration the photocatalytic performance was significantly enhanced up to 1000 μmol•g −1 •h −1 . 19 Hence, the decoration of SiNWs with AgNPs is a possible way to enhance the light absorption in the visible spectral range and hydrogen generation rate. In this paper, three simple top-down wet-chemical-modified SiNWs with different AgNPs from electroless silver deposition (ELD), 20 silver mirror reaction (MR), 21 and native Ag particles have been investigated.…”
Highly
n-doped silicon nanowires (SiNWs) decorated with silver
nanoparticles (AgNPs) at the top, middle, and bottom were produced
using electroless silver deposition (ELD), silver mirror reaction
(MR), and native AgNPs as a reference, respectively. Subsequently,
hydrogen generation on SiNWs decorated with and without AgNPs was
evaluated. Our results show that SiNWs decorated with native and MR
AgNPs produce the highest and the lowest hydrogen amount under white
light irradiation in 3 h, respectively. Moreover, for SiNWs with native
AgNPs, the morphology of SiNWs after hydrogen generation was almost
the same as the original array of SiNWs before hydrogen release, even
after 24 h in water/ethanol (4:1; v/v) solution. However, the geometry
of SiNWs decorated without and with AgNPs by ELD and MR was collapsed
after hydrogen evolution. The detailed surface studies show that the
sidewall surface of SiNWs with native AgNPs has a rougher topology
and formed a stable layer of SiO
x
in water.
Our observations strongly suggest that two hydrogen generation possibilities,
i.e., SiNW oxidation and photostimulation, are jointly responsible
for the efficient hydrogen generation. Additionally, the presence
of AgNPs on the sidewall of the SiNW matrix can enhance the hydrogen
generation rate. Our results open novel perspectives for the effective
hydrogen generation based on nanostructured silicon.
“…1 Silicon has established itself as one of the major semiconducting materials thanks to its high structural quality with suitable electronic properties such as band gap (1.12 eV), mobility, capability to be n or p doped and passivated by forming an insulating SiO 2 layer. Silicon also holds high interest in photonics 2 as a photodetector and light emitter, photocatalysis, 3 and solar cell applications. 4 Silicon based solar cells with an efficiency up to 26.7% represented about 95% of the worldwide production in 2020.…”
We have monitored the temporal evolution of the band bending at controlled silicon surfaces after a fs laser pump excitation. Time-resolved surface photo-voltage (SPV) experiments were performed using time resolved...
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