A facile preparation of Ag2O/P25 photocatalyst for selective reduction of nitrate

Ren, Haitao; Jia, Shao‐Yi; Zou, Ji‐Jun; Wu, Shuai; Han, Xu

doi:10.1016/j.apcatb.2015.03.038

Cited by 130 publications

(59 citation statements)

References 41 publications

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“…Under the experimental conditions employed, none of the materials used showed any photocatalytic activity in the reduction of nitrate. The result was not entirely unexpected given that previous reports have shown that TiO2 alone is either inactive (Bems et al, 1999;Jin et al, 2004) or slightly active (Ren et al, 2015;Rengaraj and Li, 2007) or very active. (Sá et al, 2009).…”

Section: Photocatalytic Removal Of Nitrate and Oxalic Acidsupporting

confidence: 62%

Use of carbon-based composites to enhance performance of TiO2 for the simultaneous removal of nitrates and organics from aqueous environments

Adamu

Shand

Taylor

et al. 2018

Environ Sci Pollut Res

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The simultaneous photocatalytic removal of nitrate from aqueous environment in presence of organic hole scavenger using TiO has long been explored. However, the use of unmodified TiO in such reaction resulted in non-performance or release of significant amount of undesirable reaction products in the process, a problem that triggered surface modification of TiO for enhanced photocatalytic performance. Previous studies focused on decreasing rate of charge carrier recombination and absorption of light in the visible region. Yet, increasing active sites and adsorption capacity by combining TiO with a high surface area adsorbent such as activated carbon (AC) remains unexploited. This study reports the potential of such modification in simultaneous removal of nitrates and oxalic acid in aqueous environment. The adsorptive behaviour of nitrate and oxalic acid on TiO and TiO/AC composites were studied. The Langmuir adsorption coefficient for nitrate was four times greater than that of oxalic acid. However, the amount of oxalic acid adsorbed was about 10 times greater than the amount of nitrate taken up. Despite this advantage, the materials did not appear to produce more active photocatalysts for the simultaneous degradation of nitrate and oxalic acid. The photocatalytic activity of TiO and its carbon-based composites was improved by combination with CuO particles. Consequently, 2.5 CuO/TiO exhibited the maximum photocatalytic performance with 57.6 and 99.8% removal of nitrate and oxalic acid, respectively, while selectivity stood at 45.7, 12.4 and 41.9% for NH, NO and N, respectively. For the carbon based, 2.5 CuO/TiO-20AC showed removal of 12.7% nitrate and 80.3% oxalic acid and achieved 21.6, 0 and 78.4% selectivity for NH, NO and N, respectively. Using the optimal AC loading (20 wt%) resulted in significant decrease in the selectivity for NH with no formation of NO, which unveils that selectivity for N and low/no selectivity for undesirable products can be manipulated by controlling the rate of consumption of oxalic acid. In contract, no nitrate reduction was observed with CuO promoted TiO-T and its TiO-(T)-20AC, which may be connected to amorphous nature of TiO-T and perhaps served as charge carrier trapping sites that impeded activity.

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Section: Photocatalytic Removal Of Nitrate and Oxalic Acidsupporting

confidence: 62%

Use of carbon-based composites to enhance performance of TiO2 for the simultaneous removal of nitrates and organics from aqueous environments

Adamu

Shand

Taylor

et al. 2018

Environ Sci Pollut Res

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“…In addition, since rGO accelerates electron transport, the combination of photoexcited electrons and holes decreases leads to an increased duration of photocatalytic activity [118]. TiO 2 has facilitated many pollutant degradation processes such as the reduction of nitrate, the degradation of acid fuchsin, the decomposition of acetaldehyde, and the dechlorination of CCl 4 [119][120][121][122]. Due to the continued proliferation of environment pollutants, TiO 2 and other nanostructured materials should be vigorously developed in the future to improve the degradation of pollutants by photocatalysis.…”

Section: Degradation Of Air Pollutantsmentioning

confidence: 99%

Titanium Dioxide: From Engineering to Applications

et al. 2019

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Titanium dioxide (TiO2) nanomaterials have garnered extensive scientific interest since 1972 and have been widely used in many areas, such as sustainable energy generation and the removal of environmental pollutants. Although TiO2 possesses the desired performance in utilizing ultraviolet light, its overall solar activity is still very limited because of a wide bandgap (3.0–3.2 eV) that cannot make use of visible light or light of longer wavelength. This phenomenon is a deficiency for TiO2 with respect to its potential application in visible light photocatalysis and photoelectrochemical devices, as well as photovoltaics and sensors. The high overpotential, sluggish migration, and rapid recombination of photogenerated electron/hole pairs are crucial factors that restrict further application of TiO2. Recently, a broad range of research efforts has been devoted to enhancing the optical and electrical properties of TiO2, resulting in improved photocatalytic activity. This review mainly outlines state-of-the-art modification strategies in optimizing the photocatalytic performance of TiO2, including the introduction of intrinsic defects and foreign species into the TiO2 lattice, morphology and crystal facet control, and the development of unique mesocrystal structures. The band structures, electronic properties, and chemical features of the modified TiO2 nanomaterials are clarified in detail along with details regarding their photocatalytic performance and various applications.

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“…The modification of titania with silver nanoparticles (NPs) or mixed silver forms (Ag(0), Ag + , Ag 2+ ) to prepare photocatalysts has already been performed by many research groups [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. However, in the case of Ag 2 O/TiO 2 system, there are only a few research papers and the mechanism of the coupling is still not fully understood [38][39][40][41][42][43][44][45][46][47][48][49]. The consequence of the p-n heterojunction is the movement of the photogenerated electrons to the conduction band of n-type TiO 2 and the photogenerated holes to the valence band of p-type Ag 2 O, which promotes an interfacial electron transfer causing the reduction of the charge recombination effect [42].…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic and Antimicrobial Properties of Ag2O/TiO2 Heterojunction

et al. 2019

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Ag2O/TiO2 heterojunctions were prepared by a simple method, i.e., the grinding of argentous oxide with six different titania photocatalysts. The physicochemical properties of the obtained photocatalysts were characterized by diffuse-reflectance spectroscopy (DRS), X-ray powder diffraction (XRD) and scanning transmission electron microscopy (STEM) with an energy dispersive X-ray spectroscopy (EDS). The photocatalytic activity was investigated for the oxidative decomposition of acetic acid and methanol dehydrogenation under UV/vis irradiation and for the oxidative decomposition of phenol and 2-propanol under vis irradiation. Antimicrobial properties were tested for bacteria (Escherichia coli) and fungi (Candida albicans and Penicillium chrysogenum) under UV and vis irradiation and in the dark. Enhanced activity was observed under UV/vis (with synergism for fine anatase-containing samples) and vis irradiation for almost all samples. This suggests a hindered recombination of charge carriers by p-n heterojunction or Z-scheme mechanisms under UV irradiation and photo-excited electron transfer from Ag2O to TiO2 under vis irradiation. Improved antimicrobial properties were achieved, especially under vis irradiation, probably due to electrostatic attractions between the negative surface of microorganisms and the positively charged Ag2O.

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A facile preparation of Ag2O/P25 photocatalyst for selective reduction of nitrate

Cited by 130 publications

References 41 publications

Use of carbon-based composites to enhance performance of TiO2 for the simultaneous removal of nitrates and organics from aqueous environments

Use of carbon-based composites to enhance performance of TiO2 for the simultaneous removal of nitrates and organics from aqueous environments

Titanium Dioxide: From Engineering to Applications

Photocatalytic and Antimicrobial Properties of Ag2O/TiO2 Heterojunction

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