scholarly journals High surface area of porous silicon drives desorption of intact molecules

2007 ◽  
Vol 18 (11) ◽  
pp. 1945-1949 ◽  
Author(s):  
Trent R. Northen ◽  
Hin-Koon Woo ◽  
Michael T. Northen ◽  
Anders Nordström ◽  
Winnie Uritboonthail ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area

Sensitive, Selective, & Tunable Porous Silicon Gas Sensor

2004 ◽  
Vol 828 ◽  
Author(s):  
Stephen Lewis ◽  
James Gole ◽  
Peter J. Hesketh
Keyword(s):  
Porous Silicon ◽  
Surface Area ◽  
Gas Sensor ◽  
Linear Response ◽  
High Surface ◽  
High Surface Area ◽  
Gas Response ◽  
Nanoporous Layer ◽  
General Method ◽  
Fft Analysis

ABSTRACTHybrid porous silicon, consisting of a microporous framework whose walls are covered with a thin nanoporous layer, proves to be an inexpensive and robust platform for fabrication of rapid, reversible, and sensitive semiconductor sensors. An extremely high surface area provides a mechanism for the detection of ppm and ppb levels of a range of gases including ammonia, NOx, and CO. A general method of coating electroless metal onto the surface provides a basis for nanostructure induced selectivity between these gases. Further, the introduction of FFT analysis to the rapidly reversible and linear response of the porous silicon gas sensor allows the gas response to be acquired and filtered on a drifting baseline.

Extremely High Surface Area Metallurgical-Grade Porous Silicon Powder Prepared by Metal-Assisted Etching

2011 ◽  
Vol 14 (5) ◽  
pp. K25 ◽  
Author(s):  
A. Loni ◽  
D. Barwick ◽  
L. Batchelor ◽  
J. Tunbridge ◽  
Y. Han ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Silicon Powder

Synthesis and Characterization of Mesoporous Silicon Spheres from Solid Silica Spheres

2011 ◽  
Vol 675-677 ◽  
pp. 1069-1072 ◽  
Author(s):  
Jiang Zhu ◽  
Chang Gong Meng
Keyword(s):  
Porous Silicon ◽  
Surface Area ◽  
Quantum Confinement Effect ◽  
Single Point ◽  
High Surface ◽  
High Surface Area ◽  
Silica Spheres ◽  
Mesoporous Silicon ◽  
Silicon Spheres

A well known method was used to convert the solid silica spheres to porous silicon spheres with high surface area, with the starting shape retained. The presented work demonstrated that the porous silicon spheres are composed of polycrystal morphology. Due to the quantum confinement effect, the photoluminescence emission centered at 621 nm. The results of N2 adsorption and desorption analysis indicates the mesoporous silicon spheres possess a surface area around 88 m2 g-1 and single point micro-pore volume 0.173 cm3 g-1.

Synthesis of High Surface Area Porous Silicon Carbide by Employing Soft Template in the Sol-Gel Process

2010 ◽  
Vol 148-149 ◽  
pp. 1629-1633
Author(s):  
Dong Hua Wang ◽  
Xin Fu
Keyword(s):  
Silicon Carbide ◽  
Porous Silicon ◽  
Surface Area ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Silica Xerogel ◽  
Porous Silicon Carbide ◽  
Gel Method ◽  
Sol Gel Process

High surface area porous silicon carbide was synthesized by a modified sol-gel method. In the sol-gel method, furfuryl alcohol and tetraethoxysilane were used respectively as carbon and silicon precursors for preparing a carbonaceous silica xerogel. Polymethylhydrosiloxane (PMHS) was employed as pore-adjusting agent in the sol-gel process. SiC was obtained by the carbothermal reduction of the carbonaceous silica xerogel at 1300 oC in argon flow and then purified by removing excess silica, carbon and other impurities. XRD、FTIR、SEM、HRTEM and BET were used to characterize the SiC samples. The results show that the SiC products are found to have high specific surface area of 135 m2 /g. PMHS has important effect on the surface area, pore volume of the SiC products. It is therefore suggested that PMHS plays the role of structure-directing agent that enhances the production of mesoporous pores in the SiC products.

Integrating Colloidal Quantum Dots with Porous Silicon for High Sensitivity Biosensing

2011 ◽  
Vol 1301 ◽  
Author(s):  
Girija Gaur ◽  
Dmitry Koktysh ◽  
Sharon M. Weiss
Keyword(s):  
Porous Silicon ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
High Sensitivity ◽  
Detection Sensitivity ◽  
Detection Scheme ◽  
Mode Detection ◽  
Cdte Qds ◽  
Refractive Index Increase

ABSTRACTWe aim to utilize the high surface area of a porous silicon (PSi) matrix coupled with semiconductor quantum dot (QD) amplifiers for ultrasensitive optical detection of small biomolecules using a dual-mode detection scheme. In our system, QDs attached to the target biomolecule serve as signal amplifiers by providing an additional refractive index increase beyond that of the smaller target molecules. The strong photoluminescence (PL) from the QDs serves as a secondary indication of target molecule attachment in the pores. A resulting increase in optical thickness of ∼190 nm and detection sensitivity of ∼700 nm/RIU have been demonstrated for attachment of glutathione capped CdTe QDs in the porous silicon matrix. Reflectance and PL measurements, combined with simulations, have been used to characterize the surface area coverage of the QDs within the porous framework, which is estimated at 10% for glutathione capped CdTe QDs.

Synthesis of High Surface Area Porous Silicon Carbide by a Modified Sol-Gel Method

2011 ◽  
Vol 194-196 ◽  
pp. 562-565
Author(s):  
Dong Hua Wang ◽  
Xin Fu
Keyword(s):  
Silicon Carbide ◽  
Porous Silicon ◽  
Surface Area ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Porous Silicon Carbide ◽  
Gel Method ◽  
Sol Gel Method ◽  
Sol Gel Process

High surface area porous silicon carbide was synthesized by employing polymethylhydrosiloxane (PMHS) as soft template in the sol-gel process. In the sol-gel method, furfuryl alcohol and tetraethoxysilane were used respectively as carbon and silicon precursors for preparing a carbonaceous silica xerogel. PMHS was employed as pore-adjusting agent in the sol-gel process. The purified SiC sample was characterized by XRD、FTIR、SEM、HRTEM and BET. The results show that the SiC products are found to have high specific surface area of 125 m2 /g and an average pore diameter of about 17 nm. PMHS has important effect on the surface area of the SiC products.

High surface area thermoplastic polymer films fabricated by mechanical tearing using nano-porous silicon

2016 ◽  
Vol 150 ◽  
pp. 71-73 ◽  
Author(s):  
Keren Hakshur ◽  
Leeya Engel ◽  
Yosi Shacham-Diamand ◽  
Shlomo Ruschin
Keyword(s):  
Porous Silicon ◽  
Surface Area ◽  
Polymer Films ◽  
High Surface ◽  
High Surface Area ◽  
Thermoplastic Polymer

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

2019 ◽  
Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Layer ◽  
Active Surface ◽  
Active Surface Area ◽  
High Concentration ◽  
Copper Electrodes ◽  
Surface Enhanced ◽  
Local Current

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>

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