The Artificial Photosynthesis Based On The Metal Oxides Semiconductors

A large portion of energy consumption today is from nature gas, oil and coal. Aswe all know, these energy source is not sustainable and the combustion product ishazdous to environmental and human living. Therefor, it is desirable to look forreproducible and harmless energy as the solar energy, which have attracted intenseinterest over the world. Generally, we could harvest the energy via photovolatagecell or photocatalysis system. But the photoelectrochemical cell might holdadvantages to utilize the solar energy to chemical fuels as the hydrogen throughwater splitting.Photoelectrochemical water splitting holds promising future to harvest the solarspectrum. Especially, the hematite semiconductors are widely used as thephotoanodes. Because the hematite material is more easily available, holdingrelatively stability and approapriate bandgap to absorb large portion of sunlight.Nanostructuring the hematite is an effective method to separate the electron-holepairs and the electrochemical surface area.In this work, we focus on the modifying the surface of hematite, doping thehematite and improving the interface between hematite and FTO substrate. And wedesign and synthesis highly effective WO3/BiVO4nanostructures and obtain very highphotocurrent density.Firstly, we introduce ATO particles between the hematite and FTO to formcore/shell structures to reduce the recombination possibility and improve theefficiency of hematite PEC water splitting. Then we found tha hematite nanorodsgrewn ATO modified FTO could be high temperature resistant, which could maintain the excellent morphology of hematite nanorods and increase the photocurrentdensity of hematite photoanodes.Next, we dope Zn and Ti into hematite via electrochemical-deposition methods byimproving the carrier density and increase the hematite surface kinectic dynamics toehance the hematite PEC water splitting efficiency. Furthermore, we have got Tiuniformly hematite nanorods through ALD and achieved photocurrent density of2.6mA/cm2after Co treatment, comparable to Si doped hematite of the art-of-statestructure designed by Michael group.Then, we introduce ultrathin TiO2film between hematite and FTO, whichsuccesffuly lowering the activation temperature from800degrees to600degrees.Based on this, we have synthesized3D branched hematite nanorods to improve themid-visible light absorbance and the water splitting efficiency.Finally, we first synthesized very thin WO3nanosheets, vertical to the FTO substrate.After BiVO4quantum sized particle modification, the photocurrent density archived4.2mA/cm2.We have designed and synthesized semiconductors and arcived very highphotocurrent density via approapriate modification. It is belived the hematite watersplitting efficiency would further enhanced by introducing more effectively catalystand combination methods, which would contribute much to the practical use of PECdevice.