Indium Phosphide Quantum Dots Integrated with Cadmium Sulfide Nanorods for Photocatalytic Carbon Dioxide Reduction

Abstract

Photocatalytic conversion of CO 2 into storable fuels is an attractive way to simultaneously address worldwide energy demands and environmental problems. Semiconductor quantum dots (QDs) have gained prominence as candidates for photocatalytic applications due to their many advantages, which include tunability for advanced electronic, optical, and surface properties. Indium phosphide (InP) quantum dots are semiconducting QDs with enormous potential for solar-driven CO 2 reduction. Their advantages include a tunable bandgap, diverse surface chemistry, and nontoxicity. InP QDs and CdS nanorods were integrated using a simple and inexpensive method. CO 2 photoreduction by the CdS-InP composites was evaluated in aqueous solution using triethanolamine as a sacrificial donor. The crystal structures, surface compositions, and morphologies were investigated via X-ray diffraction analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy, respectively. The UV-visible diffuse reflectance spectra of the CdS-InP composites indicated efficient visible light utilization in the 500-550 nm range. The results of photoelectrochemical and photoluminescence analyses illustrated effective charge separation in the composites. The photocatalytic activity of the as-synthesized composites was superior to that of pure CdS. The CO evolution rate of the optimized composite was 216 μmol h À 1 g À 1 during the first three hours of irradiation and increased steadily over the next 62 hours. We also studied the influences of different solvents, the hole scavenger concentration, and catalyst loading on the performance of the optimized composite.

Efficient CO2 Electroreduction on Ag2S Nanodots Modified CdS Nanorods as Cooperative Catalysts

“…Recently, Hou and coworkers have also demonstrated the incorporated sulfur in Cd surface alters the selectivity of CO 2 reduction to CO product [15] . Unfortunately, although the CdS nanorods exhibit excellent FE for CO 2 ‐to‐CO reduction, the current density remains undesirable due to the semiconductor characteristics [16] . Promoting the CO 2 reduction activity, especially the CO partial current density, is still of great importance to CdS based electrocatalysts.…”

InP-Quantum Dot Surface-Modified TiO2 Catalysts for Sustainable Photochemical Carbon Dioxide Reduction

“…InP-based QDs are well suited for diverse biological and environmental applications due to their attractive features of low toxicity and a broad absorption coverage in the solar spectrum. − In particular, compared to the most popularly studied CdSe-cored QDs, the smaller bulk band gap and larger Bohr exciton radius, which extend the corresponding absorption range to the lower energies, enable InP-based QD materials to be the most potent photosensitizer. − However, environmentally benign InP-cored QD materials have intrinsic structural vulnerabilities originating from the defect sites in the deep in-gap states , and the oxidative defects. , Therefore, InP-based QD materials are not widely studied for application in artificial photosynthesis, ,, although there are few interesting reports on the quantum dot light-emitting diode display , and water-splitting H 2 generation. , In particular, such utilization is seen to be more difficult in photocatalytic reaction for CO 2 reduction since the photosensitizing component experiences full exposure to reactive species with bearing successive redox processes during photocatalysis. − …”

“…30−32 However, environmentally benign InP-cored QD materials have intrinsic structural vulnerabilities originating from the defect sites in the deep in-gap states 33,34 and the oxidative defects. 35,36 InP-based QD materials are not widely studied for application in artificial photosynthesis, 29,37,38 although there are few interesting reports on the quantum dot light-emitting diode display 39,40 and water-splitting H 2 generation. 28,31 In particular, such utilization is seen to be more difficult in photocatalytic reaction for CO 2 reduction since the photosensitizing component experiences full exposure to reactive species with bearing successive redox processes during photocatalysis.…”

InP-Bovine Serum Albumin Conjugates as Energy Transfer Probes

“…More importantly, below the dimensions of exciton Bohr radius, the photoluminescence (PL) of QDs can be tuned to a desired wavelength in the spectral window of ultraviolet to infrared by engineering their size and shape. , Besides, QDs show several distinct properties that make them ideal bioprobes: large surface area allowing the binding of multiple target molecules, broad absorption features permitting selective excitation, high chemical and photochemical stability (fatigue resistance), narrow PL spectral width providing high color purity, particularly in bioimaging, and long PL lifetimes (50–100 ns), eliminating the interference from the autofluorescence of biological matrices (3–7 ns) . Relatively more covalent III–V semiconductor QDs that are devoid of toxic metal ions, particularly InP QDs, have garnered significant attention in recent years for both electron and energy transfer applications. , Potential applications of InP QDs have been demonstrated as sensitizers in photovoltaic devices and photoelectrodes, as blends in active charge transport layers, phototransistors, photocatalysts for hydrogen evolution, CO 2 reduction, and C–C bond formation, and as biological fluorophores …”

“…8 Relatively more covalent III−V semiconductor QDs that are devoid of toxic metal ions, particularly InP QDs, have garnered significant attention in recent years for both electron and energy transfer applications. 9,10 Potential applications of InP QDs have been demonstrated as sensitizers in photovoltaic devices 11 and photoelectrodes, as blends in active charge transport layers, 12 phototransistors, 13 photocatalysts for hydrogen evolution, 14 CO 2 reduction, 15 and C−C bond formation, 16 and as biological fluorophores. 17 The promising prospects of InP/ZnS QDs as Forster resonance energy transfer (FRET) donors in conjunction with chromophoric dye acceptors was first demonstrated by our group, paving the path for fascinating energy transfer applications.…”