In Situ One-Pot Synthesis of C-Decorated and Cl-Doped Sea-Urchin-like Rutile Titanium Dioxide with Highly Efficient Visible-Light Photocatalytic Activity

Abstract

Titanium dioxide (TiO 2 ) that offers high light-harvesting capacity and efficient charge separation holds great promise in photocatalysis. In this work, an in situ one-pot hydrothermal synthesis was explored to prepare a C-decorated and Cl-doped sea-urchin-like rutile TiO 2 (Cl-TiO 2 /C). The growth of sea-urchin-like 3D hierarchical nanostructures was governed by a mechanism of nucleation and nuclei growth−dissolution−recrystallization growth from time-dependent morphology evolution. The crystal morphology and the content of Cl and C could be controlled by the volume ratio of HCl to TBOT. Systematic studies indicated that the 0.4Cl-TiO 2 /C sample (the volume ratio of HCl to TBOT was 0.4) exhibited the highest visible-light photocatalytic activity for the degradation of rhodamine B, with kinetic rate constant (k) of 0.0221 min −1 , being 6.5 and 3.75 times higher than that of TiO 2 and Cl-TiO 2 . The enhanced photocatalytic performance could be attributed to the high charge separation and transfer efficiency induced by Cl-doping and C decoration and the excellent light-harvesting capacity caused by its sea-urchin-like nanostructure. Moreover, the 0.4Cl-TiO 2 /C sample exhibited good reusability and excellent structural stability for five cycles. This facile one-pot approach provides new insight for the preparation of a TiO 2 -based photocatalyst with excellent photocatalytic performance for potential application in practical wastewater treatment.

Quantum Dot-Embedded Hybrid Photocatalytic Nanoreactors for Visible Light Photocatalysis and Dye Degradation

“…The photoconversion ( C ) versus time ( t ) plot was fitted according to the first-order kinetics Taking log e on both sides and rearranging where C 0 is the concentration of Fe 3+ , RhB, and MB at initial time t = 0, C t is the concentration of Fe 3+ , RhB, and MB at any time t during the photocatalytic reduction, and k is the rate constant. This approach involved the calculation of the rate constant from the first-order rate equation −ln­( C t / C 0 ) versus time as reported previously. , …”

“…Next, to further illustrate the efficient visible light harvesting potential of embedded QDs inside the NDs, we utilized these NDs toward photocatalytic dye degradation in aqueous solution. Toward this end, RhB and MB were chosen as two model water soluble organic dyes known to contaminate the water body. ,,, The estimated K for RhB and MB inside the NDs in pH 7.4 aqueous solution is found to be 10 ± 1 and 12 ± 1, respectively (Figure S13). Importantly, the mean size and morphologies of dye-loaded NDs remain unaltered upon preferential sequestration (Figure S14).…”

“…Toward this end, RhB and MB were chosen as two model water soluble organic dyes known to contaminate the water body. 2,46,65,66 The estimated K for RhB and MB inside the NDs in pH 7.4 aqueous solution is found to be 10 ± 1 and 12 ± 1, respectively (Figure S13). Importantly, the mean size and morphologies of dye-loaded NDs remain unaltered upon preferential sequestration (Figure S14).…”

“…This approach involved the calculation of the rate constant from the first-order rate equation −ln(C t /C 0 ) versus time as reported previously. 43,46 2.9.3. Calculation of Conversion (%) and Photodegradation (%) Yield.…”

“…In our present work, we have fabricated a QD-embedded hybrid coacervate ND and utilized it as an efficient photocatalytic nanoreactors to drive a one-electron photoredox conversion of ferricyanide (Fe 3+ ) to ferrocyanide (Fe 2+ ) and the photocatalytic dye degradation of rhodamine B (RhB) and methylene blue (MB). Both these types of photocatalytic transformations (Fe 3+ to Fe 2+ conversion and environmentally toxic dye degradation) have been utilized extensively to evaluate the catalytic efficacy of various nanocatalysts. ,− However, bare NPs often exhibit ligand poisoning and unwanted agglomeration during the course of the reaction, which limits their catalytic efficacy and recyclability, respectively. , Our present nanoreactor comprises multiple luminescent QDs electrostatically bound with the positively charged polymer PDADMAC (Scheme ).…”