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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Degradation of tartrazine and hydrogen production simultaneously with combination of photocatalysis-electrocoagulation
摘要： Degradation of tartrazine dye and the production of hydrogen simultaneously with a combination of photocatalysis and electrocoagulation has been investigated. The photocatalytic process was performed by using a catalyst of TiO2 nanotubes that had been synthesized by anodizing method. In electrocoagulation process used Al-SS 316 electrode with variation of voltage: 5V, 10V, and 15V. The structure of TiO2 catalyst with nanotubes morphology was characterized by SEM-Mapping, FTIR, XRD, and UV-Vis DRS. The optimum condition obtained from the electrocoagulation process is at a voltage of 15V with a test time of 4 hours. From the results of photocatalysis with TiO2 nanotubes obtained percent degradation of tartrazine dye equal to 48.86% and simultaneously produced 0.87 ml of H2 with concentration 3.46%. The use of aluminum plate as anode and 316 stainless steel plate as cathode in electrocoagulation process has also succeeded degrading tartrazine dye by 82.45% and produced 3.88 ml of H2 with concentration 12.14%. The result of the combination of photocatalysis and electrocoagulation process obtained degradation conversion of tartrazine dye by 90.68% with final dye concentration to 1.93 ppm and simultaneously H2 products as much as 5.97 ml with a concentration of 12.41% can be produced. The final concentration of tartrazine dye waste from combination of photocatalysis-electrocoagulation process is safe to be disposed into the environment because it meets the quality standard. In addition, the production of H2 has potential as a renewable energy source.
关键词： electrocoagulation,tartrazine,hydrogen production,TiO2 nanotubes,photocatalysis
更新于2025-09-09 09:28:46
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Shape Tailored TiO <sub/>2</sub> Nanostructures and Their Hybrids for Advanced Energy and Environmental Applications: A Review
摘要： Shape tailored TiO2 nanostructures with various dimensionality (zero to three dimension) have unique physicochemical and functional properties that facilitates its efficient energy and environment applications, e.g., solar light driven photocatalytic hydrogen generation and decontamination of organic/inorganic toxic pollutants, CO2 reduction into the hydrocarbon fuels, solar cells, supercapacitors and lithium-ion batteries etc. However, the wide band gap nature and the fast recombination of the photogenerated charge carriers in TiO2 usually limit its overall performance under solar light illumination. In this review, we present a state of the art on the fabrication techniques of shape tailored TiO2 nanostructures and the strategies employed to make the system catalytically more efficient. Though shape tailored TiO2 nanostructures with large specific surface area and highly energetic (001) facet exposed TiO2 nanostructures (2D and 3D) can enhance the photocatalytic efficiency to a reasonable extent, further surface engineering is needed for the modification of the electronic band arrangement, visible light sensitization and efficient charge separation. Herein, TiO2 heterostructures (HSs) with metal/non-metal doping, surface fluorination, plasmonic noble metal nanoparticles (NPs) and coupling with the narrow band gap suitable semiconductor (type-II) are discussed in details covering from zero dimensional to three dimensional heterostructures. The synthesis strategies, charge transfer mechanism and their participation in the photocatalysis are elaborated. Though one dimensional TiO2 HSs have been widely studied, we present the recent development of critical surface engineering strategies of two and three dimensional systems, which give rise to the excellent properties including the enlargement of surface area, light absorption capability and efficient separation of electrons/holes resulting in the superior performance in advanced applications. Based on recent breakthroughs in the field, future directions and outlook of the field are presented at the end.
关键词： Type-II Heterostructure,2D TiO2,3D TiO2,Shape Tailored TiO2 Nanostructures,1D TiO2,Visible Light Photocatalysis,Hydrogen Production,0D TiO2,Plasmonic Heterostructure
更新于2025-09-09 09:28:46
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Insight into Reinforced Photocatalytic Activity of CNT-TiO <sub/>2</sub> nanocomposite for CO <sub/>2</sub> Reduction and Water Splitting
摘要： Using titanium dioxide (TiO2) and its modified forms for photocatalytic reduction of CO2 reduction and production of hydrogen are promising routes for providing solutions to the world energy demand in the foreseeable future. Here, we report the synthesis of a series of efficient, stable TiO2 nanoparticles modified with multi-walled carbon nanotubes (CNT) via a simple, combined sonothermal method followed by a hydrothermal treatment. In comparison to bare TiO2, the synthesized CNT-TiO2 photocatalysts showed improved photocatalytic activities for CO2 reduction under UVA as well as under visible light; and water (H2O) splitting under visible light at ambient temperature and pressure. The 2.0CNT-TiO2 has performed the best for methanol, hydrogen and formic acid production from the reduction of CO2 with yield rates of 2360.0, 3246.1 and 68.5 μmol g-1 h-1 under UVA, respectively. Its potential was further tested under visible light for methanol production, 1520.0 μmol g-1 h-1. Also, the highest rate of hydrogen yield from water splitting was 69.41 μmol g-1 h-1 with 2.0CNT-TiO2 under visible light at pH 2. The primary photocatalytic reactions of CNT-TiO2 composites and their intimate structure were studied computationally. It was demonstrated that the binding of CNT to TiO2 nanoparticles are preferable at (101) surfaces compared to (001) facets. Interaction of CNT with TiO2 results in common orbitals within TiO2 band gap that enables visible light excitation of the CNT-TiO2 composites can lead to charge transfer between TiO2 and CNT; while UV light excitation can result in charge transfer in any direction, from CNT to TiO2 and from TiO2 to CNT. The latter process is operative in the presence of sacrificial electron donor TEOA.
关键词： photocatalytic reduction,CO2 reduction,UVA light,water splitting,visible light,CNT-TiO2 nanocomposite,hydrogen production
更新于2025-09-09 09:28:46
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Diagnosis of undesired scenarios in hydrogen production by photo-fermentation
摘要： This study presents the use of a machine learning method from the artificial intelligence area, such as the support vector machines, applied to the construction of data-based classification models for diagnosing undesired scenarios in the hydrogen production process by photo-fermentation, which was carried out by an immobilized photo-bacteria consortium. The diagnosis models were constructed with data obtained from simulations run with a mechanistic model of the process and assessed on both modelled and experimental batches. The results revealed a 100% diagnosis performance in those batches where light intensity was below and above an optimum operation range. Nevertheless, 55% diagnosis performance was obtained in modelled batches where pH was away from its optimum operation range, showing that diagnosis model predictions during the first observations of those batches were classified as normal operation and revealing diagnosis delay in pH oscillations. In general, results demonstrate the reliability of classification models to be used in future applications such as the on-line process monitoring to detect and diagnose undesired operating conditions and take corrective actions on time to maintain high hydrogen productivities.
关键词： hydrogen production,photo-fermentation process,mechanistic model,undesired scenarios,diagnosis models,supervised learning methods
更新于2025-09-09 09:28:46
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Photocatalytic activities using a nanocomposite of mesoporous SiO2 and CdInSe-graphene nanoparticles under visible light irradiation
摘要： The new novel ternary mesoporous SiO2/CdInSe-graphene composites with diameters of approximately 8.08 nm have been fabricated through a self-assembly method. All physical tests demonstrated that the CdInSe-graphene was successfully uniformly distributed onto the surface of the ordered mesoporous silica particles. The obtained mesoporous SiO2/CdInSe-graphene composites exhibited good photocatalytic activity for degradation of both cationic-anionic organic dye groups, as well as the decomposition of the representative phenol group of the compound under visible light irradiation. Moreover, the photocatalytic evolution of hydrogen was studied for establishing a wider application of the as-fabricated SiO2/CdInSe-graphene catalyst in the case of energy conversion. This work indicated that the combination of the mesoporous silica and CdInSe-graphene enables achievements such as an enhancement photocatalytic performance, which has potential in industrial waste management and energy conversion.
关键词： Dye decomposition,CdInSe nanoparticles,Graphene-based nanocomposite,Gallic acid degradation,Mesoporous silica,Hydrogen production
更新于2025-09-04 15:30:14
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Enhanced visible-light photoelectrochemical hydrogen evolution through degradation of methyl orange in a cell based on coral-like Pt-deposited TiO2 thin film with sub-2 nm pores
摘要： TiO2 nanoparticles exhibit good photocatalytic activity for hydrogen evolution through water splitting; however, they demonstrate weak activity under visible light irradiation due to the wide band gap of TiO2. Deposition with noble metals such as platinum, as cocatalyst, led to the red-shift of the absorption edge of rutile TiO2; however, its activity is not significant for the photoelectrochemical (PEC) degradation of azo dyes such as methyl orange (MO). Herein, we investigated the photoelectrocatalytic degradation reaction of MO in a PEC cell based on Pt-deposited TiO2 thin film. The performance of the cell increased through the formation of mesoporous coral-like structures with sub-2 nm pores and the formation of defect states on the electrode surface. UV–vis studies confirmed, when methanol was added, the PEC cell exhibited a much higher MO degradation efficiency (99.6% after 28 min UV irradiation) than in the absence of methanol (64.7%). GC–MS studies confirmed the oxidation of methanol to formaldehyde, reacting on the electrode surface, followed by the reduction of the protons into hydrogen over the Pt sites. Also, the conversion of formaldehyde to formic acid and formic acid to CO2 are possible mechanisms to increase the hydrogen evolution rate to 418 μmol/h under visible light irradiation. Reaction of adsorbed active species within the surface of coral-like TiO2 structures with sub-2 nm pores provides high activity of the proposed PEC cell for visible-light-driven water splitting. These research studies may be continued to the design of other efficient semiconductor photocatalysts.
关键词： Photoelectrocatalytic activity,Photoelectrochemical cell,Coral-like TiO2 nanopores,Hydrogen production,Dye degradation
更新于2025-09-04 15:30:14
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3D heterostructured Ti-based Bi2MoO6/Pd/TiO2 Photocatalysts for High-Efficiency Solar Light Driven Photoelectrocatalytic Hydrogen Generation
摘要： Hydrogen fuel generation using solar light via photoelectrochemical (PEC) methods can help meet growing global energy demands and decrease environmental pollution. The key to efficient PEC hydrogen production is the synthesis of solar light driven photoelectrodes with efficient charge carrier separation. Here, we designed and prepared a ternary Bi2MoO6/Pd/TiO2 photoelectrode composed of Bi2MoO6 nanosheets, Pd nanoparticles (NPs) and TiO2 nanotube arrays (NTAs) on a Ti substrate using electrochemical methods. This novel photoelectrode had good visible light absorbance and significantly improved PEC hydrogen production rates (~5 and > 15 times higher under UV-vis and visible light irradiation, respectively, compared with TiO2 NTAs). The interfacial charge transfer mechanism of Bi2MoO6/Pd/TiO2 NTAs was comprehensively studied by comparing its PEC and photoelectrocatalytic performance with other TiO2 NTAs (i.e. Pd/TiO2 NTAs, Bi2MoO6/TiO2 NTAs and Pd/Bi2MoO6/TiO2 NTAs). For Bi2MoO6/Pd/TiO2 NTAs, Pd NPs homogeneously dispersed across the inside and outside of TiO2 nanotube walls helped to tightly anchor Bi2MoO6 nanosheets onto the TiO2 surface, forming a ternary 3D heterostructure. This structure facilitated interfacial electron injection from Bi2MoO6 to TiO2, accelerating the separation of the photogenerated electron-hole pairs. And significantly enhanced the photocurrent response and hydrogen production rate were achieved compared with other TiO2 NTAs. This 3D ternary semiconductor/metal/semiconductor heterojunction provides a viable approach for designing and synthesizing highly efficient novel photocatalysts that can effectively utilize solar energy.
关键词： TiO2 nanotube arrays,Pd nanoparticles,Bi2MoO6 nanosheets,Photoelectrocatalytic hydrogen production,Ternary photocatalyst
更新于2025-09-04 15:30:14
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Ultrathin Carbon Nitride with Atomic-Level Intra-Plane Implantation of Graphited Carbon Ring Domain for Superior Photocatalytic Activity in Visible/Near-Infrared Region
摘要： Efficient photocarrier transfer and sufficient light absorption play a crucial role in improving photocatalytic H2 evolution activity. Hence, we report a conceptual design of ultrathin carbon nitride intra-plane implanted with graphited carbon ring domain (CN-GP) via thermal polymerization of polyvinyl butyral and melamine membrane, displaying obvious disparities in the decoration type compared with the adsorption of graphene on the bulk g-C3N4 surface. This unique intra-plane heterostructural CN-GP can greatly sheathe the visible/near-infrared light range, expedite electron-hole pair separation and weaken the barrier of the photocarrier transfer through their suitable energy band structures and in-built electric felds. Consequently, the CN-GP displayed remarkable photocatalytic activity under visible/near-infrared illumination by acquiring a H2 production rate of 11.33 mmol g-1 h-1, and even showed near-infrared-drived photocatalytic activity. This work presents an effective way for the rational fabrication of g-C3N4-based materials for broad-spectrum-driven photocatalysis.
关键词： Intra-plane implantation,Hydrogen production,Vis-NIR,Graphitic carbon nitride,Inter-plane decoration
更新于2025-09-04 15:30:14
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Semiconductor Heterojunctions for Enhanced Visible Light Photocatalytic H2 Production
摘要： Semiconductor-based heterojunctions have been shown to be effective photocatalytic materials to overcome the drawbacks of low photocatalytic efficiency that results from a high rate of electron?hole recombination and narrow photo-response range. In this paper, we report on the study of heterojunctions made from visible light active, graphitic carbon nitride, g-C3N4), and UV light active, strontium pyroniobate, Sr2Nb2O7. Heterojunctions made from a combination of g-C3N4 and nitrogen-doped Sr2Nb2O7 obtained at different temperatures were also studied to determine the effect of N doping. The photocatalytic performance was evaluated by using photocatalytic hydrogen evolution reaction (HER)from water g under visible light irradiation. It was found that the photocatalytic activities of as prepared heterojunctions are significantly higher than that of individual components under similar conditions. Heterojunction formed from g-C3N4 and N-doped Sr2Nb2O7 at 700oC (CN/SNON-700) showed better performance than heterojunction made from g-C3N4 and Sr2Nb2O7 (CN/SNO). A plausible mechanism for the heterojunction enhanced photocatalytic activity is proposed based on, relative band positions, and photoluminescence data.
关键词： graphitic carbon nitride,visible light photocatalysis,strontium pyroniobate,Semiconductor heterojunctions,hydrogen production
更新于2025-09-04 15:30:14
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Preparation and characterization of Pt, N-TiO2-graphene nanocomposites for hydrogen production
摘要： A hydrothermal technique was applied for the preparation of nitrogen-doped titania-reduced graphene oxide (NTRG) and platinum-nitrogen-codoped titania-reduced graphene oxide (PNTRG). Samples were characterized using various methods such as PL, UV–Vis, XRD, BET, TEM, and photocurrent testing. Production of hydrogen in the presence of visible light was selected to study the photocatalytic performance of TiO2 (T), N,TiO2 (NT), Pt, N-TiO2 (PNT), N-TiO2-rGO (NTRG) and Pt, N-TiO2-rGO (PNTRG) samples. The results reveal that the NTRG and PNTRG samples have high photocatalytic activity compared to the T, NT, and PNT samples. The photocatalytic performance of the PNTRG sample was greater than that of the T, NT, PNT and NTRG samples by 35, 3.5, 2.33 and 1.23 times, respectively. The results indicate that the increased photocatalytic activity was due to the hindered recombination rate of the photoinduced holes and electrons, an increase in the adsorption of reactants, and the shifting of the band gap energy from the ultraviolet region to the visible region. As a result, PNTRG is photocatalytically stable for five hydrogen production cycles.
关键词： N,TiO2,Hydrogen production,Pt,Graphene
更新于2025-09-04 15:30:14