| Photoelectrochemical water splitting is one of the hot spots in the field of photoelectric chemistry.Photoelectrochemical water splitting effectively converts solar energy into hydrogen energy,which provides the most ideal solution for global energy crisis and environmental pollution.Hematite（α-Fe2O3）has been found as one of the most promising photoanode materials due to its suitable band gap of 2.0-2.2 eV,which is able to absorb 40%of solar spectrum.In this work,we have preparedα-Fe2O3photoanode through hydrothermal method,and improved its photoelectrochemical performance by doping new element and loading cocatalyst.In the first part,Ge dopedα-Fe2O3 photoanode is prepared by hydrothermal method.It is the first time using GeO2 as a doping source,which avoids the process of preparing colloid of Ge substance.Ge facilities the preferred oriented growth of the（110）plane ofα-Fe2O3 which possesses a high conductivity.The photoresponse range and intensity ofα-Fe2O3 photoanode are improved after Ge doping.As a quaternary ion,Ge displaces the position of Fe ion in lattice,which improves the density of charge carriers and restrains the recombination of electron-hole pairs.Under AM 1.5 G simulated sunlight,Ge doped photoanode shows a photocurrent density of 0.92 mA·cm-2 at 1.23 V vs.RHE,which is much higher than that obtained by pureα-Fe2O3(0.47mA·cm-2)under the same condition.In addition,we design a heterostructure by loading WO3 cocatalyst on the surface ofα-Fe2O3 photoanode.The heterostructure promotes the transmission of charge carriers and hinders the recombination of electron-hole pairs.At the same time,the loaded WO3 makes a good combination withα-Fe2O3.Thereby,the absorption efficiencies and electrical conductivity are effectively improved.Under AM 1.5 G simulated sunlight,the photoanode with WO3 loaded shows a photocurrent density of1.02 mA·cm-2 at 1.23 V vs.RHE,which is 137%higher than that obtained by pureα-Fe2O3 under the same condition. |
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