Study On The Design And Fabrication Of Photoelectrochemical Biofuel Cells And Application

The traditional sources of energy such as coal,oil and natural gas have supplied the world with energy that drives society for long decades.With the development of human society,the demand for energy is increasing.To satisfy our society's global sustainable energy demands,utilizing renewable energy such as wind,biomass and solar is one of the most promising strategies.Biofuel cells(BFCs)are a type of energy conversion device that use biocatalysts(microbe,complete living cells or enzymes)to convert the chemical energy of a fuel into electrical energy.BFCs with high biocatalytic activity offer a clean energy alternative to fossil fuels in that they can use cheap,environmentally friendly,renewable fuels(e.g.,sugars),wastewater,and even glucose endogenously existing in biological systems to produce electrical energy.All these unique characteristics make BFCs more attractive applications such as sensors using power outputs as analytical signals,or implantable power sources that are fueled by endogenous substances such as glucose in the blood stream.Currently,the main bottle-neck problems in BFCs are their fuel incomplete oxidation,short life-time and low-power density,which hamper the broad practical applications of BFCs.To address these issues,photoelectrochemical biofuel cells(PFCs)offer a model to enhance multiple energy conversion and application in reality.The main research contents of this paper are as follows:(1)A paper-supported glucose/O₂ biofuel cell(BFC)-based self-powered sensing platform for visual analysis was developed.The BFC device utilized gold nanoparticle-modified paper fibers as the electrode to wire glucose oxidase(GOx)and bilirubin oxidase for the fabrication of bioanodes and biocathodes.During the BFC operation,undesired H₂O₂,the side product of glucose oxidation which would be deleterious for GOx,was generated,leading to inevitable degeneration of BFC performance.On the basis of the H₂O₂-mediated iodide oxidation reaction to form iodine that further modulated the starch chromogenic reaction,undesired H₂O₂ could be effectively removed,resulting in remarkably improved BFC performance as well as providing a means for visual signal readout.Thanks to the dual output signals(maximum power output density or length of blue bar),enhanced analysis reliability was achieved.Moreover,this study demonstrates a proof of concept in visualized BFC-based self-powered systems for sensing applications and provides a blueprint to advance future sensors and analysis devices powered by BFCs.(2)One solar-driven electrochromic photoelectrochemical fuel cell(PFC)with highly efficient energy conversion and storage is easily constructed to achieve quantitative self-powered sensing.Layered bismuth oxyiodide-zinc oxide nanorod arrays(Zn O@Bi OI NRA)with a core/shell p-n heterostructure are fabricated as the photoanode with electrochromic Prussian blue(PB)as the cathode.The core/shell p-n heterostructure for the Zn O@Bi OI photoanode can effectively boost the photoelectrochemical(PEC)performance through the improvement of photon absorption and charge carrier separation.The optimal assembled PFC yields an open-circuit voltage of 0.48 V with the maximum power output density as high as 155?W·cm^-2 upon illumination.Benefitting from the interactive color-changing behavior of PB,the cathode not only exhibits cathodic catalytic activity in the PFC but also serves as an electrochromic display for self-powered sensing.(3)Photoelectrochemical fuel cells(PFCs)serve as a model system for harvesting electric energy from solar and biomass based on anodic fuel oxidation and cathodic oxygen reduction reaction(ORR).However,the sluggish ORR thereby limits the performance of PFC.Herein,we present a novel photocathode with polyterthiophene coated p-type cuprous oxide(p TTh-Cu₂O)that achieves boosted ORR kinetics,as well as exhibits remarkably improved photostability.By utilizing a hydrogel electrolyte which can avoid the leakage and volatilization of liquid electrolyte,a quasi-solid-state PFC device with eminent stability that consists of gold nanoparticles decorated Ti O₂ nanorod arrays(Au-Ti O₂ NRAs)photoanode and p TTh-Cu₂O photocathode can be assembled.And the fabricated PFC exhibits outstanding performance that yields an open circuit voltage of 0.78 V and a maximum power density of 130?W·cm^-2 utilizing glucose as feeding under illumination.(4)A bias-free photoelectrochemical cell(PEC)using metalorganic frameworks(MOFs)modified WO₃ nanoplates(WO₃-MOF)and Z-Scheme heterostructure of Bi VO₄ modified black phosphorus(Bi VO₄-BP)for overall water splitting was proposed.It was found that there was an enhanced solar absorbance efficiency,effective charge separation and charge transfer processes in semiconductors as well as the reaction kinetics and mechanism at the semiconductor/electrolyte interface.As a result,a tandem PEC was developed for unassisted overall water splitting.Thanks to the fact that WO₃ processes excellent pseudo-capacitive performance,under illumination,part of the photogenerated charges generated by WO₃ is stabilized by the cations and stored in situ within the WO₃ framework.This light-induced storage of charges is subsequently utilized in dark conditions in an on-demand manner for hydrogen evolution and is able to be recharged in the successive illumination cycles.