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Papers by parisa zeinalkhani
Catalysis Science & Technology, 2020
The catalytic ability of the uni-electrodic photoelectrochemical system to synthesize ammonia can... more The catalytic ability of the uni-electrodic photoelectrochemical system to synthesize ammonia can be electrostatically boosted by applying a non-faradaic potential bias to the photodevice/reactor or adding a promoter species into the reaction medium.
Journal of CO2 Utilization, 2017
Fuel shortage, energy crisis and boundless dumping of greenhouse gases into the atmosphere, are s... more Fuel shortage, energy crisis and boundless dumping of greenhouse gases into the atmosphere, are some challenging issues of human societies. To overcome these energy-related/environmental problems, solar conversion of CO 2 to carbon-based fuels is a promising route, which is achievable through the atomistic hydrogenation of CO 2 molecules inside semiconductor-assisted water-photosplitting reactors. In this paper, using a facile hydrothermal method, an eco-friendly, low-price, nanocomposite solar-energymaterial was synthesized in the absence and presence of carbon nanotube (CNT), and applied in aqueous media for the photochemical synthesis of ethanol, oxalic acid and formaldehyde. The enhancing power of CNT on the photocatalyst performance was explained in detail in terms of its ability to harvest more incident photons, temporarily store H atoms, increase the surface area and improve the charge separation phenomenon. Based on atomistic hydrogenation hypothesis, a reaction scheme was finally proposed for each photochemically synthesized product.
Solar Energy Materials and Solar Cells, 2015
Semiconductor films play a crucial role when it comes to modern solar-based technologies to gener... more Semiconductor films play a crucial role when it comes to modern solar-based technologies to generate electricity, produce solar fuels, or convert the environmental pollutants to other harmless materials. In this paper, using an interesting simple as well as versatile electrochemical route, a nanocomposite Cu/ Zn/Sn oxide semiconductor film was fabricated on a fluorine doped tin oxide glass and investigated as a photocathode of quantum dot solar cells in a sulfide/polysulfide electrolyte solution. X-ray diffraction analyses revealed a composite nature for this electrodeposited film. A broadband light absorption was witnessed and the band gap (1.63 eV) was determined through Tauc's procedure. Scanning electron micrographs exhibited a non-smooth morphology for this composite film, which provides a greater area for heterogeneous reactions occurring upon the electrode surface. Mott-Schottky and potentiodynamic polarization plots indicated that the fabricated electrode acts as a complex p-type photocathode. The electrochemical impedance studies proved that under light irradiation, by photo-generation of charge carriers (electron-hole), the interfacial charge transfer resistance decreases and the cathodic current becomes consequently enhanced. After coating (photodeposition) with silver, a complicated photoelectrochemical response was finally observed and the findings were explained in detail.
Applied Catalysis A: General, 2017
Novel water-based photonic strategy for synthesis of ammonia and hydrazine byproduct Efficient ... more Novel water-based photonic strategy for synthesis of ammonia and hydrazine byproduct Efficient solar energy materials for N2-photofixation in aqueous media Sacrificial agent acts as an h + /OH scavenger for enhancing the photoconversion yield Photocatalytic H-atom production and ammonia photosynthesis under ambient conditions ABSTRACT: To reduce carbon dioxide emission and supply the nitrogen demand of living organisms, it is crucial to employ a green, solar-based strategy to produce ammonia in aqueous media under ambient conditions, via N2 reaction with transiently photogenerated H-atoms upon appropriate semiconductor materials. In this paper, by using a facile precipitation/calcination route, we synthesized some Fe2O3 and TiO2-based uniform nanoparticles and applied them in a water photosplitting setup to photosynthesize ammonia. The maximum yield was obtained for Fe2O3 and was interpreted in terms of its ability to temporarily store hydrogen atoms, adsorb nitrogen molecules, and harvest more photons in the visible region. Based on photocatalytic reduction of protons to H-atoms and stepwise hydrogenation of N≡N molecules on the photocatalyst surface, a reaction pathway was proposed. During this N2-photofixation process, the 3 generation of hydrazine by-product was also predicted and confirmed by empirical evidence. Moreover, the role of hole-scavenger additive was discussed in detail from physicochemical standpoint.
Catalysis Science & Technology, 2020
The catalytic ability of the uni-electrodic photoelectrochemical system to synthesize ammonia can... more The catalytic ability of the uni-electrodic photoelectrochemical system to synthesize ammonia can be electrostatically boosted by applying a non-faradaic potential bias to the photodevice/reactor or adding a promoter species into the reaction medium.
Journal of CO2 Utilization, 2017
Fuel shortage, energy crisis and boundless dumping of greenhouse gases into the atmosphere, are s... more Fuel shortage, energy crisis and boundless dumping of greenhouse gases into the atmosphere, are some challenging issues of human societies. To overcome these energy-related/environmental problems, solar conversion of CO 2 to carbon-based fuels is a promising route, which is achievable through the atomistic hydrogenation of CO 2 molecules inside semiconductor-assisted water-photosplitting reactors. In this paper, using a facile hydrothermal method, an eco-friendly, low-price, nanocomposite solar-energymaterial was synthesized in the absence and presence of carbon nanotube (CNT), and applied in aqueous media for the photochemical synthesis of ethanol, oxalic acid and formaldehyde. The enhancing power of CNT on the photocatalyst performance was explained in detail in terms of its ability to harvest more incident photons, temporarily store H atoms, increase the surface area and improve the charge separation phenomenon. Based on atomistic hydrogenation hypothesis, a reaction scheme was finally proposed for each photochemically synthesized product.
Solar Energy Materials and Solar Cells, 2015
Semiconductor films play a crucial role when it comes to modern solar-based technologies to gener... more Semiconductor films play a crucial role when it comes to modern solar-based technologies to generate electricity, produce solar fuels, or convert the environmental pollutants to other harmless materials. In this paper, using an interesting simple as well as versatile electrochemical route, a nanocomposite Cu/ Zn/Sn oxide semiconductor film was fabricated on a fluorine doped tin oxide glass and investigated as a photocathode of quantum dot solar cells in a sulfide/polysulfide electrolyte solution. X-ray diffraction analyses revealed a composite nature for this electrodeposited film. A broadband light absorption was witnessed and the band gap (1.63 eV) was determined through Tauc's procedure. Scanning electron micrographs exhibited a non-smooth morphology for this composite film, which provides a greater area for heterogeneous reactions occurring upon the electrode surface. Mott-Schottky and potentiodynamic polarization plots indicated that the fabricated electrode acts as a complex p-type photocathode. The electrochemical impedance studies proved that under light irradiation, by photo-generation of charge carriers (electron-hole), the interfacial charge transfer resistance decreases and the cathodic current becomes consequently enhanced. After coating (photodeposition) with silver, a complicated photoelectrochemical response was finally observed and the findings were explained in detail.
Applied Catalysis A: General, 2017
Novel water-based photonic strategy for synthesis of ammonia and hydrazine byproduct Efficient ... more Novel water-based photonic strategy for synthesis of ammonia and hydrazine byproduct Efficient solar energy materials for N2-photofixation in aqueous media Sacrificial agent acts as an h + /OH scavenger for enhancing the photoconversion yield Photocatalytic H-atom production and ammonia photosynthesis under ambient conditions ABSTRACT: To reduce carbon dioxide emission and supply the nitrogen demand of living organisms, it is crucial to employ a green, solar-based strategy to produce ammonia in aqueous media under ambient conditions, via N2 reaction with transiently photogenerated H-atoms upon appropriate semiconductor materials. In this paper, by using a facile precipitation/calcination route, we synthesized some Fe2O3 and TiO2-based uniform nanoparticles and applied them in a water photosplitting setup to photosynthesize ammonia. The maximum yield was obtained for Fe2O3 and was interpreted in terms of its ability to temporarily store hydrogen atoms, adsorb nitrogen molecules, and harvest more photons in the visible region. Based on photocatalytic reduction of protons to H-atoms and stepwise hydrogenation of N≡N molecules on the photocatalyst surface, a reaction pathway was proposed. During this N2-photofixation process, the 3 generation of hydrazine by-product was also predicted and confirmed by empirical evidence. Moreover, the role of hole-scavenger additive was discussed in detail from physicochemical standpoint.