The construction of efficient photocatalysts has received much attention in wastewater treatment. In this study

Nb-doped NaTaO

3

was prepared with different doping ratio by a facile hydrothermal method. The prepared catalysts were analyzed by X-ray diffraction

scanning electron microscopy

Brunauer-Emmett-Teller (BET) theory

ultraviolet–visible diffuse reflectance spectroscopy. Then the synthesized catalysts were employed to degrade a model pollutant

methylene blue (MB)

under a 250 W mercury lamp. The characterization tests confirm that Nb was successfully doped into the crystal structure of NaTaO

3

and the modified NaNb

x

Ta

1-

x

O

3

(

x

is the doping ratio;

x

= 0.25

0.5

0.75) samples were formed

which were in regular cubic shapes just like pure NaTaO

3

. The synthesized NaNb

x

Ta

1-

x

O

3

(

x

= 0.25

0.5

0.75) had improved specific surface area and narrowed band gaps compared with pure NaTaO

3

. In photocatalytic degradation experiments

NaNb

0.75

Ta

0.25

O

3

presented the best photocatalytic activity ascribed to the narrow band gap and the high surface area

degradating 95.7% of MB after 180 min of reaction

which was even twice the ability of pure NaTaO

3

. Besides

the effects of possible inorganic anions and cations in wastewater on photocatalytic degradation were investigated

. Electron spin resonance (ESR) tests and capture experiments were also conducted and a possible photocatalytic mechanism was proposed. This work provides a direction for constructing superior NaTaO

3

-based photocatalysts to be widely utilized in environmental protection.