The reporter recently learned from Inner Mongolia University that the research team led by researcher Wang Lei of the university has made new progress in the research of semiconductor light corrosion resistance, and has received recognition and support from the National Natural Science Foundation of China. The related results of Passivation Layer Helps BiVO4 Anti-Light Corrosion Research have been published recently in the international chemical journal German Applied Chemistry, which will help improve the photoelectric conversion efficiency of solar hydrogen production.

Researcher Wang Lei introduced that the new clean energy hydrogen energy has always been a research hotspot of new energy. Hydrogen production by photolysis of water is one of the main technologies for obtaining hydrogen energy, and the conversion efficiency of solar hydrogen production is the main performance index of photolysis water. The low light absorption rate and high carrier recombination rate of semiconductors are the primary factors affecting the conversion efficiency. Therefore, how to improve the photoelectric conversion efficiency is the top priority in the current photoelectric catalysis research field.

BiVO4 semiconductor has a suitable band gap width of 2.4 electron volts, good light absorption performance, and suitable conduction band position for water oxidation at low potential, making it one of the important materials in the field of solar photoelectric catalytic hydrogen production.  However, the recombination of electrons and holes in the BiVO4 material seriously affects the photo-generated charge transport, making the photoelectric catalytic performance of the solar energy lower than the theoretical value. At the same time, due to photo-corrosion, it cannot be suitable for long-term photolysis water reaction. The usual solution is to use surface co-catalyst modification to improve semiconductor charge separation efficiency, inhibit secondary charge recombination, and accelerate surface reaction kinetics.

The scientific research team has effectively improved the activity and stability of BiVO4 by improving the material preparation process and the constant potential photo-polarization test method. Studies have shown that BiVO4 without surface promoter modification can achieve 100-hour stability under intermittent testing, showing super “self-healing” characteristics.  Electrochemical tests show that the passivation layer and oxygen vacancy assisting effect generated on the semiconductor surface interface effectively reduces the recombination of semiconductor electrons and holes, improves the surface water oxidation kinetics, and inhibits photo-corrosion.