Effect of ammonia‐derived species on visible‐light photocatalytic activity of Au supported on amorphous TiO₂ activated by plasma

Abstract

Amorphous TiO 2 supported Au photocatalyst (Au/AmT) is prepared via modified impregnation method with ammonia washing, followed by cold plasma treatment to activate the photocatalysts. Residual ammonia ([NH 3 ] s ) is formed due to the hydrogen bond between surface OH groups on AmT and ammonia. The [NH 3 ] s suppressed the reduction of Au δ+ and occupied active sites, leading to a poor activity of as-prepared Au/AmT. The performance of cold plasmas in activation strongly depends on discharge gases. N 2 and O 2 plasmas not only cannot reduce Au δ+ into Au 0 but also convert [NH 3 ] s into poisoning species [NO y ] s during activation. H 2 plasma with a strong reducibility can simultaneously reduce Au δ+ and remove [NH 3 ] s , thus enabling Au/AmT to achieve the highest visiblelight photocatalytic activity in CO oxidation. K E Y W O R D S amorphous TiO 2 , Au/TiO 2 photocatalyst, cold plasma, plasma activation, surface plasmon resonance Plasma Process Polym. 2018;15:e1800095. www.plasma-polymers.com

Cold plasma treatment of catalytic materials: a review

“…Interestingly, the researchers found that the performance of the synthesized gold catalytic materials strongly depends on discharge gases and discharge parameters. Sun et al [141] used AP DBD cold plasma with various working gases to activate the amorphous TiO 2 supported Au photocatalytic material (Au/AmT) obtained via a modified impregnation method with ammonia washing. Residual ammonia ([NH 3 ] s ) was formed due to the hydrogen bond between surface OH groups on AmT and ammonia.…”

Plasma-Wind-Assisted In2S3 Preparation with an Amorphous Surface Structure for Enhanced Photocatalytic Hydrogen Production

“…A schematic of the photocatalytic hydrogen production reaction using P-In 2 S 3 is shown in Figure 6 c. After the plasma treatment of bare In 2 S 3 , the atomic arrangement of the nanosheets is altered to form an amorphous surface layer based on the bombardment from the plasma gas [ 40 , 41 , 42 ]. The amorphous region in the In 2 S 3 nanosheets creates an unsaturated coordination environment to tune the electron structure.…”

Enhancing toluene removal in a plasma photocatalytic system through a black TiO2 photocatalyst

“…The conventional TiO 2 (P25, Degussa) and B-TiO 2 (Shanghai Institute of Ceramics, China) were used as photocatalysts to construct the PPS, respectively. To prepare the photocatalyst's coating (as mentioned in the introduction), about 35 mg sample was coated on a glass substrate of 75 mm (length)×25 mm (width)×1 mm (thickness) using a drip-coating method and dried at 80 °C for 1 h [11,14]. The weight of the coated sample was controlled within 35±1 mg.…”

“…The intermediate products during the toluene removal process were also evaluated by a mass spectrometer (HPR 20 QIC, HIDEN Analytical, United Kingdom). For comparison, photocatalytic performance of the photocatalysts in toluene removal was investigated in a single-pass continuous-flow photocatalytic oxidation reactor [11,15]. A xenon lamp (within 300-800 nm range) located at the top of the quartz window of the photocatalytic oxidation reactor was used as the light source [16], and the light intensity on the surface of the photocatalysts was measured by an optical power and energy meter (PM100USB, Thorlabs, USA) [11].…”

“…Photocatalysts in the PPS show significant influence on the performance of VOC removal, since they contribute to the activity of the PPS and also largely determine the distribution of products. Currently, titania (TiO 2 ) is the most-used photocatalyst due to its low cost, nontoxicity and superior stability [10,11]. Nevertheless, owing to its wide band gap (>3.0 eV), the conventional TiO 2 only exhibits ultraviolet (UV) photocatalytic activity, which limits the utilization of visible light emitted from the discharge.…”