Amorphous oxygen-rich molybdenum oxysulfide Decorated p-type silicon microwire Arrays for efficient photoelectrochemical water reduction

Abstract

We report the fabrication of p-type silicon (Si) photocathodes consisting of well-ordered Si microwire (Si-MW) arrays coupled with non-precious and earth-abundant amorphous oxygen-rich molybdenum oxysulfide (MoO x S y ) as both a hydrogen evolution catalyst and a passivation layer. The MoO x S y is conformally grown on the Si-MW surface through photo-assisted cyclic voltammetric (CV) deposition. By adjusting the cycle numbers of the CV deposition, Si-MW array electrodes with different MoO x S y catalyst loadings (Si-MWs@MoO x S y ) have been obtained and comprehensively characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Xray photoelectron spectroscopy (XPS), and Raman and Fourier-transform infrared spectroscopies. The photoelectrochemical performance of the Si-MWs@MoO x S y cathodes toward water reduction is investigated and compared with that of platinum nanoparticle decorated Si-MW array electrodes (Si-MWs@PtNPs). An optimized Si-MWs@MoO x S y photocathode is found to exhibit activity comparable to that of the Si-MWs@PtNPs one, with a much better stability in acidic medium. In neutral electrolyte, Si-MWs@MoO x S y outperforms Si-MWs@PtNPs in terms of both activity and stability. Given the low materials cost, easy and well-established electrode fabrication procedure, and high 1 3 5 7 Please cite this article as: X.-Q. Bao, et al., Amorphous oxygen-rich molybdenum oxysulfide Decorated p-type silicon microwire Arrays for efficient photoelectrochemical water reduction, Nano Energy (2015), http://dx.doi.org/10.1016/j.nanoen.2015.06.014demonstrated photoelectrochemical performance, the Si-MWs@MoO x S y arrays reported here hold substantial promise for use as low-cost and efficient photocathodes for water reduction.

Strategies for Semiconductor/Electrocatalyst Coupling toward Solar‐Driven Water Splitting

“…Using PECD, other HER catalysts, e.g., MoS x O y , CoMoS x , NiCoSe x , and CoP, have also been reported to couple to different photocathodes for light‐driven H 2 production. In many cases, the catalyst layers are usually directly photodeposited on semiconductor photoelectrodes without introducing an interlayer, and they offer, besides high catalytic activity, good passivation to semiconductors against corrosion given their exceptional electrochemical stability, exhibiting promising bi‐functionality.…”

Freestanding Metallic 1T MoS2 with Dual Ion Diffusion Paths as High Rate Anode for Sodium‐Ion Batteries

“…Even though 2H semiconducting MoS 2 has been investigated for Li + intercalation, water splitting, and catalysis, this is the first application of 1T MoS 2 for Na + intercalation. The obtained 1T MoS 2 electrode has a high reversible capacity of 313 mAh g −1 at a current density of 0.05 A g −1 after 200 cycles and a capability of 175 mAh g −1 at a high current density of 2 A g −1 .…”

Molecular and Material Engineering of Photocathodes Derivatized with Polyoxometalate-Supported {Mo3S4} HER Catalysts

“…26 We thus report an effective method to improve the time stability of the photocathode by using the electrostatic entrapment of the negatively charged thio-POM into a cationic polymer film, namely poly(3,4-ethylenedioxythiophene) (PEDOT). This method is applied on microstructured silicon surfaces 12,17,27,28 in order to considerably improve light absorption to yield robust photocathodes with appreciable solar-driven HER activity observed above 0 V vs Reversible Hydrogen Electrode (RHE). (Figure 1).…”