Photoirradiation-Induced Capacitance Enhancement in the h-WO₃/Bi₂WO₆ Submicron Rod Heterostructure under Simulated Solar Illumination and Its Postillumination Capacitance Enhancement Retainment from a Photocatalytic Memory Effect

Abstract

Recently, photoassisted charging has been demonstrated as a green and sustainable approach to successfully enhance the capacitance of supercapacitors with low cost and good efficiency. However, their light-induced capacitance enhancement is relatively low and is lost quickly when the illumination is off. In this work, a novel active material system is developed for supercapacitors with the photoassisted charging capability by the decoration of a small amount of Bi 2 WO 6 nanoparticles on an h-WO 3 submicron rod surface in situ, which forms a typical type II band alignment heterostructure with a close contact interface through the co-sharing of W atoms between h-WO 3 submicron rods and Bi 2 WO 6 nanoparticles. The photogenerated charge carrier separation and transfer are largely enhanced in the h-WO 3 /Bi 2 WO 6 submicron rod electrode, which subsequently allows more charge carriers to participate in its photoassisted charging process to largely enhance its capacitance improvement under simulated solar illumination than that of the h-WO 3 submicron rod electrode. Furthermore, the h-WO 3 /Bi 2 WO 6 submicron rod electrode could retain its photoinduced capacitance enhancement in the dark for an extended period of time from the photocatalytic memory effect. Thus, our work provides a solution to the two major drawbacks of reported supercapacitors with the light-induced capacitance enhancement property, and supercapacitors based on active materials with the photocatalytic memory effect could be utilized in various technical fields.

Photo-assisted charging of carbon fiber paper-supported CeO2/MnO2 heterojunction and its long-lasting capacitance enhancement in dark

“…Even after 12 h in dark, ~56% of its capacitance enhancement from the photo-charging was still retained, which was far higher than that in Ref. [77] on the h-WO 3 /Bi 2 WO 6 material system (16% retainment after only 5 h in dark) from the photocatalytic memory effect. To create photo-generated electron storage by reducing Mn 4+ to Mn 3+ with the proper Mn 4+ /Mn 3+ reduction potential successfully avoided their reaction with O 2 , which largely slowed down their release and was critical for the observed long-lasting photo-assisted capacitance enhancement of the CeO 2 /MnO 2 -CFP electrode in dark.…”

In Situ Growth of Cs3Bi2Br9 Quantum Dots on Bi-MOF Nanosheets via Cosharing Bismuth Atoms for CO2 Capture and Photocatalytic Reduction

“…51 In addition, the cosharing Bi atoms between Bi 2 S 3 and BiVO 4 via the in situ solvothermal sulfurization pathway built an atomic-level contact in the BiVO 4 @Bi 2 S 3 hybrid, which not only accelerated the carrier transport efficiency but also enhanced the bonding linkage between the components to largely promote the activity and reusability. 52 Several other cosharing atom materials (such as Cs 3 Bi 2 I 9 /Bi 2 WO 6 , 53 Cs x WO 3 /CsPbBr 3 , 54 SnO 2 /SnSe 2 , 55 WO 3 /Bi 2 WO 6 56 ) have been fabricated, and all showed multiple tunnels for carrier transport.…”

Exploring a Ni–N4 Active Site‐Based Conjugated Microporous Polymer Z‐Scheme Heterojunction Through Covalent Bonding for Visible Light‐Driven Photocatalytic CO2 Conversion in Pure Water

“…39‐0256). [ 21 ] Raman spectra were obtained to investigate the chemical composition of the samples (Figure 2E). The Bi 2 WO 6 exhibited two typical peaks at 711 and 795 cm −1 , matching to the tungstate chain asymmetric stretching modes and the anti‐symmetric stretching modes of the O–W–O bond, respectively.…”