Highly Active TiO_2-xN_x Visible Photocatalyst Prepared by N-Doping in Et₃N/EtOH Fluid under Supercritical Conditions

Abstract

TiO2- x N x nanocrystallines were prepared by treating the TiO2 precursor in triethylamine/ethanol (Et3N/EtOH) fluid under supercritical conditions. During photodegradation of p-chlorophenol under irradiation with visible lights, this catalyst exhibits much higher activity than the N-doped TiO2 obtained via direct calcination. The promoting effect of the supercritical treatment could be attributed to the high surface area, the highly crystallized anatase, and the strong interaction of N-dopants with TiO2, leading to the enhanced light harvesting and reactant adsorption as well as quantum efficiency of photocatalysis via inhibiting the recombination between photoinduced electrons and holes. Supercritical treatment using Et3N/EtOH fluid results in higher N-content in the TiO2- x N x than that using NH3/EtOH fluid. Even with the same N-content, the TiO2- x N x obtained in Et3N/EtOH is still much more active than that obtained in NH3/EtOH fluid, possibly owing to the enhanced surface hydrophobicity which could promote the adsorption of reactant molecules for degradation.

Photocatalytic activity of (sulfur, nitrogen)-codoped mesoporous TiO2 thin films

“…Asahi et al [9] have prepared N-doped TiO 2 materials that exhibited visible-light activity. Subsequently, TiO 2 photocatalysts doped with either anions (N [10][11][12][13], C [14][15][16][17][18], S [19][20][21], F [22,23], P [24], I [25], etc.) or cations (Fe [26], Co [27], Pt [28], Cu [29], etc.)…”

Photocatalytic Activity and Electronic Structure Analysis of N‐doped Anatase TiO2: A Combined Experimental and Theoretical Study

“…To utilize solar energy effectively, many attempts have been made to modify the optical property of TiO 2 . Since doping of elements could efficiently extend the photoresponse of TiO 2 to the low-energy region [3], a substantial amount of research work has focused on improving the absorption of visible light (400-800 nm) by doping with C [4], N [5], S [6], F [7], I [8], and so on.…”

Microwave-assisted synthesis of Ag-doped MOFs-like organotitanium polymer with high activity in visible-light driven photocatalytic NO oxidization

“…For comparison, the N-doped TiO 2 was also prepared under supercritical conditions [19]. Briefly, 2.5 mL of 1.0 M HNO 3 aqueous solution was mixed with 10 mL ethanol, followed by adding dropwise into a solution comprised of 40 mL ethanol and 10 mL of Ti(OC 4 H 9 ) 4 at 25 • C under vigorous stirring.…”