Efficient Visible-Light Photocatalytic Properties in Low-Temperature Bi-Nb-O System Photocatalysts

Table 1 The grain sizes, specific surface areas, and UV-vis absorption data of Bi-Nb-O powders sintered at different temperatures

Catalysts	BNO500	BNO550	BNO600	BNO650	BNO700	BNO750	BNO800
Grain size (nm)	30~40	~60	70~80	~100	100~200	~200	300~400
Specific surface areas (m²/g)	9.7	11.2	10.5	10.3	12.2	11.6	7.9
Band gap (eV)	2.88	2.83	2.89	2.88	2.78	2.88	2.91
λ ^a (nm)	431	439	429	431	447	431	427

^aMaximum absorptive wavelength is estimated from the intercept of the tangents to the plots