Fabrication Of α-Fe₂O₃ And G-C₃N₄ For Photoelectrochemical Performance Study

With the rapid development of economy, culture, science and technology in the 21 st century, the demand of energy is also increasing. As well as all known, people use amount of fossil fuels, however, the storage capacity of fossil fuels is limited, moreover, the products of combustion can cause serious environment pollution, therefore, energy shortage and environment pollution attract the attention from all over the world. More and more countries have already devoted to exploring the new, green, clean and efficient energy strategies. People found hydrogen energy is accord with people’s requirement of energy, that not only efficient but also friendly for environment. How can maximum limit and effective acquire hydrogen energy, namely, which need to be explored another new strategy.A large number of studies have found that can not only make hydrogen energy, at the same time also won’t cause any pollution to the environment by water splitting hydrogen. People found that solar water splitting to hydrogen is a highly effective method by using semiconductor photocatalyst. So, the researchers began to further explore semiconductor photocatalyst materials with more efficient photocatalytic activity, α-Fe₂O₃ and g-C₃N₄ are the semiconductor photocatalysts with high photocatalytic performance and low cost, thus, it has drawn wide attention of the researchers. On the basis of predecessors’ s work, this paper further studied how to improve the α-Fe₂O₃ and g-C₃N₄ photocatalytic performance.The first part of the paper mainly introduces the exploration about energies, people in order to study the preparation of the new, green and clean energies devote many research works. And we made a detailed overview about solar water splitting hydrogen production technology, the principle and electrode materialsIn order to further improve α-Fe₂O₃ film photoelectrochemical performance, in the second part of this paper, we introduce how to dope α-Fe₂O₃ film by electrochemical deposition with Sn, after that annealed at different high temperatures. Finally, the film was modified by Co（NO₃）2.6H2 O, after the experimental process α-Fe₂O₃ film with best photocatalytic activity. From the results obtained, the preparation of the film samples morphology by SEM, XRD, XPS, EIS and so on, furthermore, by examining the photocurrent response of the sample film to detect the photoelectrochemical performance. Experimental results show that under the irradiation of the AM 1.5 G 100 mw/cm2 visible light, optimization of the sample in 1.24 V vs RHE showed a higher anode current response（2.8 mA/cm2）, and photocurrent is 4.6 mA/cm2 before the start of the dark current, which is equivalent to 0.24% of the total photoelectric conversion efficiency. Samples have an excellent light response mainly because of electrical conductivity, the charge transfer and the improvement of water oxidation kinetics, and all the improvement is mainly the increase of the carrier density and the result of the sample surface with Co2+ decoration.In the third part of this paper, firstly, we introduce prepared a layer of g-C₃N₄ thin film on FTO substrate and TiO₂ seed layer, through high temperature annealing under atmosphere of nitrogen. Secondly, the gold nanorods were doped effectively. After, annealing in the different high temperature to obtaine maxium the photoelectrochemical performance in experimental progress and about the sample film of the morphology and the optical current response test by means of SEM and XRD were excellent. The experimental results showed that using gold nanorods doping the pure graphite carbon nitride（g-C₃N₄） could enhance the photocurrent to a large extent, This is mainly because the metal nanorods can largely improve the charge separation, finally the graphite carbon nitride（g-C₃N₄） of the conductivity and the semiconductor photocatalytic performance were greately improved.In the forth of this paper,we mainly introduce the experimental procedure about after preparing a layer of g-C₃N₄ thin film was doped by gold nanorods or not, we further synthesized the compound semiconductor materials: g-C₃N₄/TiO₂ NWs and Au/g-C₃N₄/TiO₂ NWs by simple hydrothermal synthesis method. Then, after annealing at different high temperatures（300℃, 500℃） and testing photocurrent response, we found the Au/g-C₃N₄/TiO₂ NWs sample has the highest photocurrent after annealing in the 500℃. which was mainly due to the formation of doping compounds or compound semiconductor material made separation of electrons and holes effectively. Meanwhile, the Au/g-C₃N₄/TiO₂NWs-500℃ film can further strengthen its photocatalytic hydrolysis reaction speed and efficiency of hydrogen production.