Enhancement in Photoelectrochemical Efficiency by Fabrication ofBiVO4@MWCNT Nanocomposites

Abstract

An enormous enhancement in the photo-to-current conversion efficiency over the nanocomposite material composed by BiVO 4 on the surface of MWCNTs, with respect to electrode of pure BiVO 4 , was observed. The heterojunction formed between MWCNTs and nano-BiVO 4 is beneficial for the separation of photogenerated electrons and holes, resulting in more electrons that are able to transport efficiently to the surface and therefore enhance the photoefficiency.

Progress in bismuth vanadate photoanodes for use in solar water oxidation

“…Recently BiVO 4 has been combined with reduced graphene oxide (RGO) and carbon nanotubes to form composite electrodes in the hope of improving the electron transport in the BiVO 4 electrodes. 53, 54 Ng et al prepared GO/ BiVO 4 composites by stirring bismuth(III) nitrate, vanadium(v) oxide, and graphene oxide in a nitric acid solution. When these composites were suspended in an ethanol solution and illuminated, the photoexcited electrons in BiVO 4 reduced GO to RGO and the RGO-BiVO 4 composite resulted.…”

“…The major limiting factors identified include (i) significant recombination of photogenerated electron-hole pairs, (ii) poor electrical conductivity and (iii) a slow hole transfer kinetics for water oxidation. 34,36,48,49 Recently, many attempts have been made to address one or more of these issues, which include controlling morphologies, 35,37,42,[49][50][51] forming composite structures or heterojunctions, 49,[51][52][53][54][55][56][57] doping or composition tuning, [33][34][35][38][39][40][41]48,58,59 and coupling with oxygen evolution catalysts (OECs). [33][34][35][36]40,43,46,48,51,60 This section will give an overview of each of these strategies and discuss how these modifications affected the photoelectrochemical performance of BiVO 4 .…”

“…82,83 The enhanced photocurrent was also observed when a multi-walled carbon nanotube (MWCNT)/BiVO 4 composite electrode was prepared and compared to the bare BiVO 4 electrode. 54 It was concluded that the reason for the enhancement is the good contact between MWCNT and BiVO 4 as well as MWCNT acting as good electron transfer media.…”

Advanced chemical compositions and nanoarchitectures of bismuth based complex oxides for solar photocatalytic application

“…Besides the effective charge separation from their heterostructure, the improved photocatalytic performance in these systems is inevitably associated with the extended energy response of photo-excitation, leading to enhanced charge carriers generation under visible light irradiation. [171][172][173][174][175][176][177][178][179][180][181][182][183][184][185] Among these carbon materials, GO composite materials obtained the most attention recently, owing to its perfect conjugated sp 2 -hybridized carbon structure and large BET surface area. The conjugated sp 2 -hybridized structure provides abundance of delocalized electrons to enhance the transport of photo-generated electrons.…”