A synergetic effect of rare earth (Yb) ion doping and ammoniation on the enhancements of both ultraviolet and visible photocatalytic activities of TiO2 is reported. It is found that ammoniation can dope both nitrogen and hydrogen ions for bandgap narrowing and dangling bond passivation, respectively. Meanwhile, the Yb-doping results in the formation of defective bands that are close to the conduction band minimum, and have strong electron capture abilities to prevent recombination of photogenerated electrons and holes. The synergism of the two effects of Yb doping and ammoniation leads to a significant enhancement of both ultraviolet and visible photocatalysis. (C) 2018 Elsevier B.V. All rights reserved.