Progress, Challenge, and Perspective of Bimetallic TiO₂-Based Photocatalysts

Table 2

Recent publications of TiO₂ photocatalysts modified bimetallic nanoparticles used in oxidation processes.

Bimetallic NPs	Average particle size [nm]	Irradiation source	Degradation effect and comments	Reference
Ag-Au alloy; Ag (shell)-Au (core)	17	n.d.	Structure depends on the molar ratio between Ag and Au. Higher Ag ratios result in an increase in silver shell on the surface of Ag/Au alloy core, while lower Ag ratios tend to the formation of alloy particles	[39]
Ag-Cu alloy	5 to 6	1000 W Xe arc lamp	The photodegradation efficiency under visible light increased with the increase in copper loading up to 0.5 mol% and then decreased	[69]
Au-Cu alloy	3 to 5	300 W Xe arc lamp	Modification of Cu leads to better enhancement in the photocatalytic properties compared to modification of Au. The best photocatalyst is Au-Cu/P25 with Au-Cu 1 : 3	[70]
Au-Cu alloy	3	n.d.	The bimetallic Au-Cu/TiO2 catalysts showed higher activity in terms of methanol conversion and hydrogen selectivity than the monometallic Au/TiO2 and Cu/TiO2 catalysts	[71]
Pt-Cu alloy	2 to 6	Xe arc lamp cut-off filter (𝜆>450 nm)	Bimetallic alloy nanoparticles consisting of 80 mol% of Pt and 20 mol% of Cu, supported on anatase TiO2, successfully promote aerobic oxidation of alcohols under sunlight irradiation at ambient temperature	[53]
Pt-Pd alloy	1 to 12; depending on metal precursors amount	1000 W Xe arc lamp cut-off filter (𝜆>420 nm)	The best photocatalytic activity was observed for the sample Pt-Pd/TiO2 modified with 0.5 mol% of platinum and 0.5 mol% of palladium. Average degradation rate of 6.84 𝜇mol dm^−3min^−1 for phenol was about 19 times greater than for pure TiO2 obtained using the same preparation procedure	[30]
Pt-Pd alloy	2 to 4	100 W high pressure mercury lamp	The optimum loading of platinum around 0.5–1.0% was observed for the photocatalytic oxidation of methyl orange dye. The photocatalytic activity of Pd/TiO2 decreased with the increase of palladium loading	[78]