Novel TiO₂/C₃N₄ Photocatalysts for Photocatalytic Reduction of CO₂ and for Photocatalytic Decomposition of N₂O

Abstract

TiO/g-CN photocatalysts with the ratio of TiO to g-CN ranging from 0.3/1 to 2/1 were prepared by simple mechanical mixing of pure g-CN and commercial TiO Evonik P25. All the nanocomposites were characterized by X-ray powder diffraction, UV-vis diffuse reflectance spectroscopy, photoluminescence, X-ray photoelectron spectroscopy, Raman spectroscopy, infrared spectroscopy, transmission electron microscopy, photoelectrochemical measurements, and nitrogen physisorption. The prepared mixtures along with pure TiO and g-CN were tested for the photocatalytic reduction of carbon dioxide and photocatalytic decomposition of nitrous oxide. The pure g-CN exhibited the lowest photocatalytic activity in both cases, pointing to a very high recombination rate of charge carriers. On the other hand, the most active photocatalyst toward all the products was (0.3/1)TiO/g-CN. The highest activity is achieved by combination of a number of factors: (i) specific surface area, (ii) adsorption edge energy, (iii) crystallite size, and (iv) efficient separation of the charge carriers, where the efficient charge separation is the most decisive parameter.

g‐C3N4‐Based Heterostructured Photocatalysts

“…Many gC 3 N 4 based systems showed enhanced separation efficiency of photogenerated charge carriers, for example, by coupling gC 3 N 4 with a second semiconductor, such as TiO 2 , [272,279] Ag 3 PO 4 , [280] In 2 O 3 , [98] ZnO, [171,281] LaPO 4 , [282] Bi 2 WO 6 , [274] CeO 2 , [283] WO 3 , [186] AgX (X = Cl and Br), [284] NaNbO 3 , [285] BiOI, [176] CdS, [286] and CdMoO 4 . Many gC 3 N 4 based systems showed enhanced separation efficiency of photogenerated charge carriers, for example, by coupling gC 3 N 4 with a second semiconductor, such as TiO 2 , [272,279] Ag 3 PO 4 , [280] In 2 O 3 , [98] ZnO, [171,281] LaPO 4 , [282] Bi 2 WO 6 , [274] CeO 2 , [283] WO 3 , [186] AgX (X = Cl and Br), [284] NaNbO 3 , [285] BiOI, [176] CdS, [286] and CdMoO 4 .…”

Photocatalytic decomposition of N2O over TiO2/g-C3N4 photocatalysts heterojunction

“…This can be achieved by coupling two semiconductors with the different band gaps and suitable band edge positions [15]. TiO 2 /g-C 3 N 4 composites were widely studied for the photocatalytic degradation of pollutants [5,13,[16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”

Coupling of Bifunctional CoMn‐Layered Double Hydroxide@Graphitic C3N4 Nanohybrids towards Efficient Photoelectrochemical Overall Water Splitting

“…[6,7,27,[30][31][32][33][34][35][36][37] Additionally,g -C 3 N 4 catalysts are also applied for other energy conversion techniques (such as CO 2 reduction and photodegradation of pollutants). [38][39][40][41][42][43][44] However,i ta lso faces some disadvantages, such as al ow surface area, inherently low electrical conductivity,a nd easy recombination of electron-hole pairs. The bandgap (2.7 eV) leads to low absorption of the solars pectrum above l = 460 nm.…”