Visible Light Active Phosphorus-Doped TiO₂ Nanoparticles: An EPR Evidence for the Enhanced Charge Separation

Abstract

Phosphorus-doped TiO2 nanoparticles with visible light activity were prepared by sol–gel method by using Ti(IV) isopropoxide and phosphoric acid as precursors. As prepared samples were calcined at different temperatures, and the obtained samples were characterized by X-ray diffraction, UV–vis spectroscopy, Brunauer–Emmett–Teller (BET) surface area analysis, X-ray photoelectron spectroscopy, scanning emission microscopy, electron paramagnetic resonance (EPR) spectroscopy, the photodegradation of methyleneblue (MB). The results indicate that phosphorus-doping into TiO2 lattice decreases the particle size, increases the thermal stability of titania, and retards the phase transition from anatase to rutile. UV–vis absorption of the P-doped samples shows the redshift in its absorption edge. Doped phosphorus exists in a pentavalent oxidation state by replacing part of lattice Ti4+ by the formation of Ti–O–P bonds. MB degradation profiles with visible light irradiation show that the photocatalytic activity of P-doped Titania is much enhanced and superior to undoped TiO2 and commercial Degussa P25. Low temperature EPR studies with in situ visible light irradiation on the samples heated at different temperatures clearly demonstrates that enhanced charge separation is the major reason for the enhanced photocatalytic activity.

Palladium Nanoparticles Anchored on Anatase Titanium Dioxide‐Black Phosphorus Hybrids with Heterointerfaces: Highly Electroactive and Durable Catalysts for Ethanol Electrooxidation

“…Similar to phosphorusdoped TiO 2 , the P atoms originating from BP can be squeezed and diffused into the ATN lattice, allowing the Ti 4+ sites to be replaced by P species and the BP nanoflakes to be connected with cataclastic ATN via the formation of TiOP bonds (Inset of Figure 3c). [30] The incorporation of the ATN and BP nanoflakes was further confirmed by the lattice fringes of both BP and the ATN in the HRTEM image. Figure 3h illustrates the existence of lattice spacings of 0.335 and 0.262 nm, which correspond to the (021) and (040) With the ATN-BP hybrids used as support, the Pd/ATN-BP catalysts were prepared using K 2 PdCl 4 as the precursor and KBH 4 as the reductant.…”

Improved visible light photocatalytic activity of fluorine and nitrogen co-doped TiO2 with tunable nanoparticle size

“…A series of nonmetal elements including N [5][6][7][8], F [9][10][11], S [12], C [13,14] and P [15,16] have been explored, which show that these nonmetal dopants are able to expand the light absorption edge of TiO 2 to the region of visible light thus to improve the photocatalytic activity of materials. In particular, fluorine and nitrogen doping are intensively used for the modification of TiO 2 materials due to their marked thermal stability and cost-effectiveness [17,10].…”

Synergistic Effects of Phosphorus and Cobalt Binary Doping on Visible Light Activity of TiO2 by Sol-Gel Method and Evaluation of Photocatalytic Efficiency

“…From these results decrease in crystallite size was observed due to codoping of cobalt and phosphorus into TiO2 lattice. The variation in the particle size and the phase content demonstrated that P doping decreases the particle size, aggravate the unit cell distortion, retards the phase transformation of anatase to rutile [34] and the reducing atmosphere due to P-doping was more efficient in slowing down the crystal-growth rate in P, Co-codoped TiO2 [35,36]. The comparative results of pure TiO2, single doped, phosphorus and cobalt codoped crystallite size with codoped TiO2 are given in the Table 2.…”