Synthesis of Yb3Â +/Ho3Â + co-doped Bi2WO6 upconversion photocatalyst with highly improved visible light photocatalytic activity

As a novel visible-light-driven photocatalyst, Yb3 +/Ho3 + co-doped Bi2WO6 (Yb3 +/Ho3 +-Bi2WO6) was synthesized via a simple hydrothermal method and subsequent a calcination process. The as-synthesized Yb3 +/Ho3 +-Bi2WO6 samples were characterized by various analytical methods. The BIW-5 (Yb3 +/Ho3 + molar ratios is 5) sample showed the highest photocatalytic activity. The RhB was degraded (99.8%) under visible light irradiation in 20 min. The improved photocatalytic activity could be attributed to the efficient energy transfer between Yb3 +/Ho3 + and Bi2WO6 via infrared to visible upconversion and the reduced combination rate of photogenerated electron-hole pairs through doping Yb3 +/Ho3 + ions. Therefore, this study may provide a better method to obtain stable upconversion photocatalyst with greatly improved activity.