Green synthesis of carbon quantum dots embedded onto titanium dioxide nanowires for enhancing photocurrent

Abstract

The green synthesis of nanowired photocatalyst composed of carbon quantum dots-titanium hybrid-semiconductors, CQDs/TiO2, are reported. Where graphite-based CQDs with a size less than 5 nm are directly synthesized in pure water electrolyte by a one-step electrochemistry approach and subsequently electrodeposited onto as-prepared TiO2 nanowires through a voltage-driven reduction process. Electron paramagnetic resonance studies show that the CQDs can generate singlet oxygen and/or oxygen radicals to decompose the kinetic H2O2 intermediate species upon UV light illumination. With the effect of peroxidase-like CQDs, photocurrent density of CQDs/TiO2 is remarkably enhanced by a 6.4 factor when compared with that of as-prepared TiO2.

Incorporation of Mn 2+ into CdSe quantum dots by chemical bath co-deposition method for photovoltaic enhancement of quantum dot-sensitized solar cells

“…The photoelectric conversion efficiency (PCE) of DSSCs based on a planar substrate of a rigid conducting glass has reached greater than 11% [2,3]. Replacing the organic dyes by semiconductor quantum dots (QDs) in sensitizers, quantumdot-sensitized solar cells (QDSSCs) exhibit the unique advantages of quantum size effect, multi-exciton effect, large absorption coefficient and easy matching of energy levels between the electron donor and acceptor materials [4,5]. QDs, which include CdS, CdSe, CdTe [6], PbS [7], Ag 2 S [8], Ag 2 Se [9], CuInS 2 [10][11][12] and CuInSe 2 [13], are numerous.…”

A Novel Hydrogen Peroxide Amperometric Sensor Based on Hierarchical 3D Porous MnO2−TiO2 Composites

“…The Ti 2p spectrum (Figure b) shows Ti 2p 3/2 and Ti 2p 1/2 peaks at 457.7 and 463.3 eV, respectively. The corresponding deconvolution suggests the presence of two chemically distinct species of Ti 3+ and Ti 4+ , which are due to TiOOH (coordinatively unsaturated) and TiO 2 , respectively . The Mn 2p core‐level spectrum (Figure c) shows two distinct peaks at binding energies of 640.8 eV for Mn 2p 2/3 and 652.6 eV for , which were further deconvoluted into two pairs of doublets peaks at 642.5/653.4 and 640.6/652.1, corresponding to the Mn(IV) and Mn(III) species, respectively.…”

Biomolecules Oxidation by Hydrogen Peroxide and Singlet Oxygen

“…Photocatalytic reaction can also produce H 2 O 2 [29][30][31][32][33][34]. For example, the surface of titanium dioxide (TiO 2 ) can reduce relatively oxidative molecules under ultraviolet A (UVA; wavelength, 315-400 nm) irradiation [29][30][31][32].…”

“…Other photocatalytic materials, for example, zinc oxide (ZnO) can photocatalyze 1 O 2 production through the similar reaction of TiO 2 photocatalysis[97]. Recently, carbon quantum dots, which have been paid attention as interesting nano-materials, also photocatalyze 1 O 2 production[33].…”