MoS2 hydrogen evolution catalysis on p-Si nanorod photocathodes

We report on the synthesis of few-layers MoS2 flakes coated on the p-Si nanorods (p-SiNRs) via the metal -organic chemical vapor deposition (MOCVD) method. The MoS2 flakes show a vertically-standing, few-layers (10-15) morphology. The photoluminescence characteristic of the MoS2/p-SiNRs heterojunction exhibits a blue-shift energy bandgap (1.65-1.78 eV) at temperature of 77 K with thinner MoS2 layers due to the quantum confinement effect. As a result, the fabricated MoS2/p-SiNRs photocathode results in a saturated photocurrent density (PCD) and a photoconversion efficiency (eta) of 42.3 mA cm(-2), and 0.64% at 0 V (vs. RHE), respectively. Due to the built-in potential of heterojunction and more active edge sites, the onset voltage of the MoS2/ p-SiNRs sample was positively shifted to similar to 0.72 V (vs. RHE). Based on this finding, we suggest that a heterojunction structure might serve an approach for fabricating the hybrid photoelectrochemical (PEC) device of the Si-based material.

Automated summary

This study demonstrated the synthesis of few-layers MoS2 flakes coated on p-Si nanorods using MOCVD, resulting in vertically-standing morphology and improved photoconversion efficiency. The MoS2/p-SiNRs heterojunction sample exhibited a positively shifted onset voltage and higher photoelectrical performance.