Polypyrrole and a polypyrrole/nickel oxide composite – single-walled carbon nanotube enhanced photocatalytic activity under visible light

Abstract

A novel NiO/PPy/SWCNT composite for removal of organic dyes with an emphasis on the effect of photocatalytic charge carrier transport and photoluminescence properties.

Pyridine-amide-based hetero-copper iodide for the photocatalytic degradation of dyes and aerosol discolouration of VOC gases

“…The h + plays a crucial role in decomposing CR into simpler ones. Electrons move from the VB of CP to the conduction band (CB), with the CB potential relative to NHE approximately at −0.54 V and −0.63 V. The electrons in the CB of CPs react with O 2 molecules dissolved in the dye solution, forming superoxide radical anions (˙O 2 − ), since the reduction potential of O 2 to ˙O 2 − is −0.18 V vs. NHE, 47 which is lower than the CB of CPs. These superoxide radicals react with H 2 O and transform into H 2 O 2 (˙O 2 − /H 2 O 2 , +0.91 V vs. NHE).…”

“…The possible mechanisms of interaction between CP 1 and solvent-free CP 2 with dyes are as follows: 47,48 hν + CPs → (h VB + + e CB − ) CPsh VB + + H 2 O → ˙OH + H + h VB + + Dye CR → colorless degraded productsO 2 + e − → ˙O 2 − (O 2 /˙O 2 − = −0.18 V vs. NHE)˙O 2 − + H 2 O → HOO˙ + OH − H 2 O + HOO˙ → H 2 O 2 + ˙OH (˙O 2 − /H 2 O 2 = +0.91 V vs. NHE)H 2 O 2 + e − → ˙OH + OH − (H 2 O 2 /˙OH = +0.39 V vs. NHE)H 2 O 2 + h + → HOO˙ + H + HOO˙ + H 2 O 2 → H 2 O + O 2 + ˙OHDye + hν → Dye*(e LUMO − + h HOMO + )Dye*(e LUMO − + h HOMO + ) + (h VB + ) CP → CP + Dye + Dye + (h HOMO + ) + ˙OH/˙O 2 − → colorless degraded products…”

“…After the electron jump, a positively charged hole (h + ) is formed on the valence band. Due to the triple state effect of CPs, in ), since the reduction potential of O 2 to O 2 À is À0.18 V vs. NHE, 47 À work together to achieve decolorization and degradation of CR. 47,48 Moreover, we had carried out the controlled photocatalytic dye degradation experiments (50 mL of 20 mg L À1 dye solutions of CR, RhB, and MB) without CP under the same conditions, respectively (Fig.…”

“…Therefore, in solvent-free CP 2, MB and RhB are hardly broken down. 47,48 The possible mechanisms of interaction between CP 1 and solvent-free CP 2 with dyes are as follows: 47,48 hn + CPs -(h VB + + e CB À ) CPs (1)…”

Photocatalytic Solar Hydrogen Generation by SWCNT-Supported Nickel Oxide Nanoparticles Wrapped by Polypyrrole

“…10 In our previous work, it has been reported that conducting polymer PPy as a cocatalyst imparts substantial enhancement in the visible light-assisted photocatalytic activity by loading NiO nanoparticles with single-walled carbon nanotubes (SWCNTs) toward organic pollutant degradation. 23 The importance of PPy in photocatalysis for its good electrical conductivity and excellent charge transport properties is due to its delocalized π conjugated electrons. 24,25 Additionally, PPy is highly stable under an ambient environment, has a comparatively low bandgap (E g ∼ 2.4 eV) for working in solar optical energy windows, and has an appropriate band edge potential level for proton reduction.…”