Photocatalytic H2 O2 Production by Thiophene-Coupled Benzotriazole and Anthraquinone-Based D-A-Type Polymer Nanoparticles.

Herein, the photocatalytic generation of an important solar fuel-H2 O2 -by a thiophene-coupled anthraquinone (AQ) and benzotriazole-based donor (D)-acceptor (A) polymer (PAQBTz) nanoparticles is systematically reported. The visible-light active and redox-active D-A type polymer is synthesized employing the Stille coupling polycondensation, and the nanoparticles are obtained by dispersing the PAQBTz polymer and polyvinylpyrrolidone solution, prepared in tetrahydrofuran to water. The polymer nanoparticles (PNPs) produce 1.61 and 1.36 mM mg-1 hydrogen peroxide (H2 O2 ) in the acidic and neutral media, respectively, under AM1.5G simulated sunlight irradiation (λ > 420 nm) with ≈2% modified Solar to Chemical Conversion (SCC) efficiency after 1 h of visible light illumination in acidic condition. The results of the various experiments lay bare the different aspects governing H2 O2 production and indicate the H2 O2 synthesis through the superoxide anion-mediated and anthraquinone-mediated routes.

Pt nanoparticles coupled with perylene-based small molecule deposited on Ti3+ self-doped TiO2 nanorods-An inorganic/organic type-II nanoheterostructure for efficient visible-light photoelectrochemical water oxidation.

In the work reported in this article, we have coupled Ti3+-self-doped TiO2 nanorods (NRs) with a newly synthesized tetrathiophene coupled perylene-based molecule (tThTMP) to form type-II inorganic/organic nanoheterostructures (NHs) for visible-light-driven water oxidation. The small organic molecule helps in better utilizing a wide range of the visible light spectrum, facilitates a faster delocalization of the photogenerated carriers at the inorganic/organic heterojunction, and exhibits improved photoelectrochemical performances. We have further decorated the NHs with platinum nanoparticles (NPs). The decoration of the Pt NPs significantly augments the various aspects of photoelectrochemical performances. The Pt NPs decorated NHs photoanode exhibits a photocurrent density of 0.83 mA/cm2 at 1.23 V vs. RHE (@10 mV/s scan rate), a photoconversion efficiency of 0.26%, a substantial cathodic shift in the water oxidation onset potential and flat band potential, impressively reduced charge transfer resistance, improved photocarrier concentration, photovoltage, and stability.

Localized surface plasmon-enhanced photoelectrochemical water oxidation by inorganic/organic nano-heterostructure comprising NDI-based D-A-D type small molecule.

This research article reports the visible-light-driven photoelectrochemical water oxidation performances of the plasmonic Au-Pd nanoparticle-decorated inorganic/organic nano-heterostructures (NHs)-B-TiO2/NDIEHTh@Au-Pd. The inorganic constituent of the NHs consists of boron-doped TiO2 nanorods (NRs) grown on fluorine-doped tin oxide (FTO) coated glass substrate. The organic part (NDIEHTh) consists of an acceptor naphthalene diimide (NDI)-based donor-acceptor-donor (D-A-D) type small molecule, in which thiophene serves as the donor. Because of the benefits of the localized surface plasmon resonance (LSPR) effect, the Au-Pd binary alloy nanoparticles substantially ameliorate the visible-light-driven photoelectrochemical performances of the B-TiO2/NDIEHTh@Au-Pd NHs photoanode compared to the B-TiO2/NDIEHTh NHs photoanode. The photocurrent densities exhibited by the B-TiO2/NDIEHTh NHs, and B-TiO2/NDIEHTh@Au-Pd NHs photoanodes at 1 V vs Ag/AgCl are 0.68 mA/cm2 and 1.59 mA/cm2, respectively, manifesting 209% and 623% increments in the photocurrent density compared to that shown by B-TiO2 NRs photoanode. Besides, the B-TiO2/NDIEHTh@Au-Pd NHs photoanode offers a significantly cathodically shifted water oxidation potential, reduced charge transfer resistance, better surface injection efficiency, and most importantly, superior photostability compared to the B-TiO2/NDIEHTh NHs photoanode. The enhancement in the different photoelectrochemical performances could be attributed to the various advantages of LSPR, such as enhanced light absorbance, light concentration, hot electron injection, and plasmon-induced resonance energy transfer.