Green synthesized plasmonic nanostructure decorated TiO2 nanofibers for photoelectrochemical hydrogen production

Abstract

We herein present the Au and Ag NPs synthesized via chemical reduction with green synthesized carbon nano lights (CNL) as a visible light photosensitizer for TiO2 nanofibers (TNFs) towards photoelectrochemical water splitting. The synthesized photoanodes (PA1: TNFs, PA2: Ag@CNLs/TNFs and PA3: Au@CNLs/TNFs) were probed ex-situ for morphological, structural, optical and electronic properties before being used for the PEC experiments. We first show the efficient photocatalytic activity of these photoanodes for the degradation of methylene blue under visible light irradiation. Followed by the photoelectrochemical (PEC) water splitting investigation, which reveals the substantially improved photocurrent density to 13 mA/cm2 and 18 mA/cm2, for PA2 and PA3, respectively under simulated AM 1.5 solar illumination at 1.36 V vs RHE, ~15 fold enhancement compared to that obtained for a PA1. This improvement we attributed to the synergic consequence, improved absorption and effective charge carrier separation & transport due to surface plasmonic effect, which is well evident in the decrease of measured charge transfer resistance (Rct), for PA2 (15.1 Ω) and PA3 (6.71 Ω), as compared to PA1 (139 Ω).