| Photoelectrochemical（PEC）water-splitting cells can convert solar energy into clean hydrogen.The photoelectrode is an important part of PEC water-splitting system,whose properties directly determine the final conversion efficiency.Therefore,the design and construction of semiconductor photoelectrodes are always the core issues in the PEC field.WO3 is widely used as photoelectrode in photoelectrochemistry due to its advantages of good visible light response,non-toxic,economy,and relatively stable chemical properties under acidic conditions.However,the high carrier recombination rate and surface oxidation kinetics of WO3 in the charge transport process seriously hamper its practical application.Focused on this,this paper studies the methods of preparation,morphology control,surface treatment and modification.Furthermore,the mechanism for performance enhancement is discussed.The research works are as follows:（1）Fabrication and optimization of WO3 photoanode.By a facile electrophoretic deposition（EPD）,WO3 photoanodes were fabricated utilizing different WO3 powders（particle size around 150nm or 23?m）.Better performance was achieved with the 150 nm WO3 powders.Moreover,the device achieves the best efficiency when the film thickness is 5.5μm,and annealing at 450°C for 1hour.（2）Post-necking treatment of WO3 photoanode.First,the EPD-prepared WO3 photoanodes were treated by ammonium metatungstate solution followed by annealing,achieving a photocurrent increase of 16 times at 1.23 VRHE.Then,three kinds of photoanodes were designed and fabricated.The results show that the enhancement of the photoanode electrical connection is a major factor for the performance improvement.（3）Modification of WO3 photoanode byα-Fe2O3.On the surface of WO3 film,α-Fe2O3 was directly prepared by hydrothermal method,forming a composite photoanode.Compared with WO3photoanode,though the photocurrents of the composite photoanode are lower,its photocurrent decays at a relatively slow rate. |
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