Nanoniobia Modification of CdS Photoanode for an Efficient and Stable Photoelectrochemical Cell

Abstract

Herein we report the surface modification of a CdS film by niobia nanoparticles via thioglycerol as an organic linker and thus fabricate an efficient and a stable photoanode for a photoelectrochemical (PEC) cell. We have synthesized three differenly sized (∼3, ∼6 ,and ∼9 nm) niobia nanoparticles by a hydrothermal synthesis approach and have further investigated the particle-size-dependent PEC performance of the nanoparticle-modified CdS photoanode. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirm the formation of Nb2O5 nanoparticles that are prepared via decomposition of the niobium peroxo complex during the hydrothermal reaction and reveal the presence of surface OH(-) groups over niobia nanoparticles that impart a high catalytic property to a material. The nano-Nb2O5-modified photoanode displayed a 23-fold higher power conversion efficiency compared to that of CdS. This modified structure increases the open circuit voltage (OCV) from 0.65 to 0.77 V, which is attributed to the nano-Nb2O5-induced surface passivation effect over bare CdS. Linking of nanoparticles on the CdS surface improves the photocorrosion stability of the CdS photoanode for even longer than 4 h in contrast to the tens of minutes for the base CdS surface. The uniform coverage of the CdS photoanode surface by niobia nanoparticles is thus found to be the controlling parameter for achieving a higher PEC performance and stability of the photoanode. This finding directed us to design an improved CdS photoanode for efficient and prolonged PEC hydrogen generation from a PEC cell.

Synthesis of core-shell structured CdS@CeO 2 and CdS@TiO 2 composites and comparison of their photocatalytic activities for the selective oxidation of benzyl alcohol to benzaldehyde

“…As shown in Table 3, the leaching amounts of Cd ions in CdS@CeO 2 is far lower than that over CdS, indicating that covering CeO 2 shell layer can effectively improve the photostability of CdS. Similarly, the previous studies also proved that coating the stable semiconductors such as ZnO, TiO 2 , and Nb 2 O 5 can effectively inhibit the photo-corrosion of CdS [58][59][60]. These results demonstrate that CdS@CeO 2 -180 is a stable photocatalyst and can be reused in the selective oxidation of benzyl alcohols.…”

Photoelectrochemical devices for solar water splitting – materials and challenges

“…30 CdS photoanodes modified with TiO 2 nanoparticles using organic linkers have also been demonstrated for longterm hydrogen production and a CdS photoanode could also be modified by nano-Nb oxides for efficient and stable photoelectrochemical water splitting. 31 Recently, a TiO 2 /CdS/Co-P i heterojunction exhibited a photocurrent of ca. 1 mA cm À2 at 1.23 V vs. RHE and reasonable stability over 2 h irradiation, due to photoelectron injection into TiO 2 from CdS and hole transfer to Co-P i for water oxidation, which to some extent alleviated the photocorrosion process.…”

Different Enhancement Mechanisms of the Anodizing Al‐Doped or Sn‐Coupled Ti3SiC2 for the Photoelectrochemical Performance

“…This delayed equilibration time can be attributed to the wide band gap of SnO 2 blocking the direct excitation of photogenerated electrons. During CPC measurement, the photogenerated electrons coming out from TiO 2 are effectively collected by SnO 2 until it reaches an optimum amount . As a result, CPC of Sn0.1‐ATSC decreases with the duration of time and then it becomes stable.…”