The influence of hydrofluoric acid etching processes on the photocatalytic hydrogen evolution reaction using mesoporous silicon nanoparticles

Abstract

In this work, the response of the photocatalytic activity of mp-Si nanoparticles to a series of HF acid treatments was investigated.

Nontypical Wulff-Shape Silicon Nanosheets with High Catalytic Activity

“…In recent years, nanoporous Si (np-Si) particles and Si nanosheets (SiNSs) have been proposed as alternatives to catalysts for hydrogen generation. Following this direction, silicon photocatalysts with high-surface-area nanostructures were demonstrated using different synthetic approaches, such as reduction of silica, − clays, , and SiCl 4 and direct exfoliation . These efforts have provided data supporting the importance of a high surface area to enhance photocatalytic performance.…”

Nanostructured silicon photocatalysts for solar-driven fuel production

“… 49 The oxide layer can be removed by treating Si nanostructures with hydrofluoric acid; however, this method involves a highly toxic reagent and the byproducts (HSiF 5 and H 2 SiF 6 ) formed during this reaction can clog pores and decrease accessible surface area. 50 Furthermore, the hydrogenated-Si surface does eventually succumb to oxidation and is not an effective strategy to improve Si catalytic activity. The future of Si photocatalysts will depend on improving their longevity while retaining the high activity that has been demonstrated in certain systems.…”

Photocatalytic hydrogen generation using mesoporous silicon nanoparticles: influence of magnesiothermic reduction conditions and nanoparticle aging on the catalytic activity

“…15,16 In recent years, nanostructured silicon (Si) has shown promise as a photocatalyst for H 2 generation. [17][18][19][20][21][22][23][24] Si is an attractive semiconductor for this application given its abundance, non-toxicity, and ability to absorb in the UV to near IR region of the solar spectrum. 22,25 While bulk Si has been wellestablished for electricity production in solar cells 26 and fuel formation in photoelectrochemical systems, 27,28 its applicability as a particulate photocatalyst remains relatively under investigated.…”

“…21,22 The mp-Si NPs for photocatalytic H 2 generation have been prepared either via reduction of SiCl 4 using a NaK alloy 21 or through magnesiothermic reduction of silica precursors. 18,20,22,24 Magnesiothermic reduction is becoming the sought-after method given its ease, scalability, and tunability. The reaction conditions of magnesiothermic reduction can be easily modified to change the physical properties such as the surface area, pore size, crystallinity, and crystallite size of the resulting mp-Si.…”