Decoration of plasmonic Cu nanoparticles on WO3/Bi2S3 QDs heterojunction for enhanced photoelectrochemical water splitting

Abstract

We report a WO3/Cu/Bi2S3 wherein incorporation of Cu nanoparticles (Cu NPs) to enhance the photoelectrochemical activity over WO3/Bi2S3. Cu NPs effectively harvest the light energy upon plasmon excitation and transfer the energy to contacted WO3, thereby improving the photoelectrochemical (PEC) performance. The WO3/Cu/Bi2S3 composite was characterized by scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray diffraction (XRD) to analyze the morphology and interfacial contact between the semiconductors. The photocurrent density and Solar-to-Hydrogen conversion efficiency for this composite is 10.6 mA cm−2 at 1.23 V (versus RHE) and 3.21% at 0.81 V (versus RHE), which are much higher than WO3/Bi2S3 with 4.02 mA cm−2 at 1.23 V (versus RHE) and 2.46% at 0.81 V (versus RHE) respectively. Moreover, the stability and photo-response of WO3/Cu/Bi2S3 were carried out through chronoamperometric studies. The composite retained its stability over 50 cycles without decay in PEC performance. High incident photon conversion efficiency (IPCE) value of about 51% is achieved which is evident from the high photocurrent density. Incorporation of Cu NPs increase the photoactivity which is evident from the photocurrent value. The increased activity of Cu NPs sandwiched composite is attributed for the quick electron transfer to semiconductor due to surface plasmon resonance (SPR) effect.