8 research outputs found
Silicon Nanowire Photocathodes for Photoelectrochemical Hydrogen Production
The performance of silicon for water oxidation and hydrogen production can be improved by exploiting the antireflective properties of nanostructured silicon substrates. In this work, silicon nanowires were fabricated by metal-assisted electroless etching of silicon. An enhanced photocurrent density of −17 mA/cm2 was observed for the silicon nanowires coated with an iron sulphur carbonyl catalyst when compared to bare silicon nanowires (−5 mA/cm2). A substantial amount of 315 µmol/h hydrogen gas was produced at low bias potentials for the silicon nanowires coated with an iron sulphur carbonyl catalyst
Silicon Nanowire Photocathodes for Photoelectrochemical Hydrogen Production
The performance of silicon for water oxidation and hydrogen production can be improved by exploiting the antireflective properties of nanostructured silicon substrates. In this work, silicon nanowires were fabricated by metal-assisted electroless etching of silicon. An enhanced photocurrent density of −17 mA/cm2 was observed for the silicon nanowires coated with an iron sulphur carbonyl catalyst when compared to bare silicon nanowires (−5 mA/cm2). A substantial amount of 315 µmol/h hydrogen gas was produced at low bias potentials for the silicon nanowires coated with an iron sulphur carbonyl catalyst
A robust ALD-protected silicon-based hybrid photoelectrode for hydrogen evolution under aqueous conditions
International audienceHydrogen production through direct sunlight-driven water splitting in photo-electrochemical cells (PECs) is a promising solution for energy sourcing. PECs need to fulfill three criteria: sustainability, cost-effectiveness and stability. Here we report an efficient and stable photocathode platform for H2 evolution based on Earth-abundant elements. A p-type silicon surface was protected by atomic layer deposition (ALD) with a 15 nm TiO2 layer, on top of which a 300 nm mesoporous TiO2 layer was spin-coated. The cobalt diimine-dioxime molecular catalyst was covalently grafted onto TiO2 through phosphonate anchors and an additional 0.2 nm ALD-TiO2 layer was applied for stabilization. This assembly catalyzes water reduction into H2 in phosphate buffer (pH 7) with an onset potential of +0.47 V vs. RHE. The resulting current density is -1.3 ± 0.1 mA cm-2 at 0 V vs. RHE under AM 1.5 solar irradiation, corresponding to a turnover number of 260 per hour of operation and a turnover frequency of 0.071 s-1
Bioengineered Silicon Diatoms: Adding Photonic Features to a Nanostructured Semiconductive Material for Biomolecular Sensing
Native diatoms made of amorphous silica are first converted into silicon structures via magnesiothermic process, preserving the original shape: electron force microscopy analysis performed on silicon-converted diatoms demonstrates their semiconductor behavior. Wet surface chemical treatments are then performed in order to enhance the photoluminescence emission from the resulting silicon diatoms and, at the same time, to allow the immobilization of biological probes, namely proteins and antibodies, via silanization. We demonstrate that light emission from semiconductive silicon diatoms can be used for antibody-antigen recognition, endorsing this
material as optoelectronic transducer
Boron-Doped Silicon Diatom Frustules as a Photocathode for Water Splitting
An
effective solar-powered silicon device for hydrogen production
from water splitting is a priority in light of diminishing fossil
fuel vectors. There is increasing demand for nanostructuring in silicon
to improve its antireflective properties for efficient solar energy
conversion. Diatom frustules are naturally occurring biosilica nanostructures
formed by biomineralizing microalgae. Here, we demonstrate magnesiothermic
conversion of boron-doped silica diatom frustules from Aulacoseira sp. into nanostructured silicon with
retention of the original shape. Hydrogen production was achieved
for boron-doped silicon diatom frustules coated with indium phosphide
nanocrystal layers and an iron sulfur carbonyl electrocatalyst