Preparation and Characterization of Ni-Doped TiO₂ Materials for Photocurrent and Photocatalytic Applications

Table 3

The initial concentrations of methylene blue (MB), the initial degradation rate (𝑟), the Langmuir-Hinshelwood adsorption equilibrium constant (𝐾_ads), and the pseudo-first-order rate constant (𝑘) of methylene blue over Ni-doped TiO₂ (Ni = 0.1, 0.5, 1, 5, and 10 at. wt.%) powders formed at 550°C for 6 h.^†

Ni (at. wt.%) in TiO2	𝐶0 of MB (ppm)	𝐾obs (h^−1) (±0.020)	𝑀 (slope)	𝐶 (intercept)	𝐾ads (× 10^−2 ppm^−1)	𝑘 (ppm h^−1)
0.1	3.198 (0.01 mM)	1.195	0.101	0.647	15.61	9.90
	6.397 (0.02 mM)	0.636
	9.595 (0.03 mM)	0.672
0.5	3.198	1.263	0.133	0.549	24.22	7.52
	6.397	0.563
	9.595	0.607
1	3.198	0.389	0.181	2.093	8.64	5.52
	6.397	0.289
	9.595	0.268
5	3.198	0.531	0.122	1.556	7.84	8.19
	6.397	0.405
	9.595	0.375
10	3.198	0.856	0.221	0.705	31.34	4.52
	6.397	0.383
	9.595	0.387

^†The values are arrived as detailed in the experimental section.