Table 5.

Undoped Bi-based nanostructured photocatalysts for remediation of dye pollution.

Photocatalyst	Target dye pollutant	Optimum experimental conditions	Source of light	Degradation (%)	Ref.
Remarks on active species
BiOI, Bi2O4	rhodamine B	treatment time: 32 min; dosage of catalyst: 0.5 g/L; initial concentration of dye: 10 mg/L	visible light (LED)	10.0, 67.0	[130]
•O2− and h+ were the main active species during the photocatalytic degradation process.
Bi4Ti3O12	rhodamine B	treatment time: 120 min; dosage of catalyst: 0.1 g/L; initial concentration of dye: 10 mg/L	visible light (Xenon lamp)	100.0	[131]
•O2− and h+ contributed mostly to the degradation process.
BiVO4	alizarin red S	treatment time: 180 min; dosage of catalyst: 0.5 g/L; initial concentration of dye: 10 mg/L	UV (365 nm)	99.6	[132]
The degradation of the dye was mainly attributed to the contribution of •OH radicals.
BiOCl	rhodamine B	treatment time: 100 min; dosage of catalyst: 1 g/L; initial concentration of dye: 9.6 mg/L	visible light	22.0	[133]
The photogenerated electrons converted the adsorbed oxygen into •O2−, which played a key role together with h+ in the degradation process.
Bi2O3	acid yellow 29, Coomassie brilliant blue, Acid Green 25	treatment time: 120 min; dosage of catalyst: 1 g/L; initial concentration of Acid Yellow 29: 0.1425 × 10−3 mg/L, of Coomassie brilliant blue: 0.427 × 10−4 mg/L, and of Acid Green 25: 0.156 × 10−3 mg/L	visible light (Halogen lamp)	Acid Yellow 29: 58.0, Coomassie brilliant blue and Acid Green 25: 57.0	[134]
•O2− and •OH radicals were the key species while h+ contributed to the production of more •OH radicals.
Bi2O2CO3	rhodamine B	treatment time: 45 min; dosage of catalyst: 0.666 g/L; initial concentration of dye: 10 mg/L	visible light	13.0	[135]
•O2− and •OH radicals were the dominant species during the photocatalytic degradation process.
BiOCl0.7I0.3	methyl orange	treatment time: 50 min; dosage of catalyst: 2 g/L; initial concentration of dye: 20 mg/L	visible light	100.0	[136]
—
Bi2WO6	rhodamine B	treatment time: 100 min; dosage of catalyst: 1 g/L; initial concentration of dye: 4.8 mg/L	visible light (Xe light)	98.2	[137]
e− and h+ contributed to the degradation process.
BiOCl	methylene blue	treatment time: 120 min; dosage of catalyst: 1 g/L; initial concentration of dye: 20 mg/L	sunlight	36.0	[138]
•O2− and •OH radicals contributed to the photocatalytic process.
BiOI	methyl orange	treatment time: 30 min; dosage of catalyst: 1 g/L; initial concentration of dye: 10 mg/L	visible light (300 W Xe lamp)	35.2	[139]
•O2− and h+ were the dominant species while the •OH radicals played a minor role in the degradation reaction.
BiVO4	rhodamine B	treatment time: 180 min; initial concentration of dye: 10 mg/L	visible light (tungsten halogen lamp)	90.0	[140]
•O2− and •OH were the dominant species.
BiOI	rhodamine B	treatment time: 240 min; dosage of catalyst: 0.25 g/L; initial concentration of dye: 10 mg/L	direct sunlight	100.0	[125]
The •OH radicals and h+ played key roles in the degradation process.
Bi2O3	methyl orange	treatment time: 240 min; initial concentration of dye: 10 mg/L	visible light	94.8	[141]
—
BiFeO3	rhodamine B	treatment time: 180 min; dosage of catalyst: 0.2 g/L; initial concentration of dye: 10 mg/L	visible light	94.0	[142]
e− converted O2 to •O2−, which contributed actively to the degradation process alongside h+.
Bi2WO6/AgIO3	rhodamine B	treatment time: 180 min; dosage of catalyst: 0.5 g/L; initial concentration of dye: 10 mg/L	visible light	100	[143]
The active species were •O2− and h+.