The Research Of Improvement Performance On TaON Photoanode

Utilizing solar energy to produce H2 from water, in the manner of photoelectrochemistry (PEC), was considered to be one of the most potential strategies to solve the energy crisis and environment problem. The semiconductors need suitable band gap, ideal visible light absorption, stable photocurrent and so on. However, due to the semiconductors are not fit the above requirements to date, we must use various methods to solve the essential issue. The approaches to achieve high efficiency in conversion of solar energy to H2 include:(1) Doping for enhancing visible light absorption in the wide bandgap semiconductor or promoting charge transport in the narrow bandgap semiconductor. (2) Removing segregation phases or surface states to achieve surface treatment. (3) Electrocatalysts which can decrease the overpotentials to improve the photoelectrochemical activity.Owing to oxynitrides semiconductors possess suitable band gap for water splitting and a narrow band gap for visible light absorption, TaON is the most potential candidates, it can produce H2 and O2 from water without an externally applied bias. In this paper, we attempt to optimize the synthesis condition and suitable cocatalyst for the purposes that mention previously.The main conclusions are as follows:(1) Utilize high temperature to eliminate the high defect density of TaON, and promote charge transport. Increasing the temperature influence the N content, lead to absorb more visible light and promote charge transport through the Mott-Schottky Theoretical.(2) Load cobalt-phosphate (Co-pi) on the surface of TaON to enhance the performance of photocatalytic efficiency. Through the electrophretic deposition (EPD) method to load cobalt-phosphate (Co-pi) on the surface of TaON, the photocurrent can achieve 2 mA cm-2(1.23VRHE, AM 1.5), the incident photon to current efficiency (IPCE) is 75%at 400 nm.