| 1. |
- Anil, Athira, et al.
(författare)
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Effect of pore mesostructure on the electrooxidation of glycerol on Pt mesoporous catalysts
- 2023
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 11:31, s. 16570-16577
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Tidskriftsartikel (refereegranskat)abstract
- Glycerol is a renewable chemical that has become widely available and inexpensive due to the increased production of biodiesel. Noble metal materials have shown to be effective catalysts for the production of hydrogen and value-added products through the electrooxidation of glycerol. In this work we develop three platinum systems with distinct pore mesostructures, e.g., hierarchical pores (HP), cubic pores (CP) and linear pores (LP); all with high electrochemically active surface area (ECSA). The ECSA-normalized GEOR catalytic activity of the systems follows HPC > LPC > CPC > commercial Pt/C. Regarding the oxidation products, we observe glyceric acid as the main three-carbon product (3C), with oxalic acids as the main two-carbon oxidation product. DFT-based theoretical calculations support the glyceraldehyde route going through tartronic acid towards oxalic acid and also help understanding why the dihydroxyacetone (DHA) route is active despite the absence of DHA amongst the observed oxidation products.
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| 2. |
- Gao, Wenqiang, et al.
(författare)
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Construction of diluted magnetic semiconductor to endow nonmagnetic semiconductor with spin-regulated photocatalytic performance
- 2023
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Ingår i: Nano Energy. - : Elsevier BV. - 2211-2855 .- 2211-3282. ; 110
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Tidskriftsartikel (refereegranskat)abstract
- Electron spinning polarization has now attracted extensive attention due to its significant effect on improving catalysis. However, only a few photocatalysts possess the electron spinning modification property. How to endow nonmagnetic semiconductors with spintronic properties to realize spinning-regulated photocatalysis enhancement is a great challenge. Herein, based on the diluted magnetic semiconductor concept, we proposed a novel strategy to endow photocatalysts a spinning tunable property. In this work, a diluted magnetic semiconductor photocatalyst with spin polarization was constructed by only doping magnetic ions into CdS/MoS2. The spin polarization with a higher ferromagnetic property was detected in CdS and MoS2 of the Ni-doped CdS/MoS2 diluted magnetic semiconductor photocatalyst. The magnetic field-derived spin polarization reduced the charge recombination in CdS, and improved the interface transfer efficiency between CdS and MoS2, which resulted in a 3.89-fold improvement of the photocatalytic hydrogen production under an external magnetic field. This work provides a new strategy to endow nonmagnetic semiconductors with spin-regulated photocatalytic performance by constructing diluted magnetic semiconductor photocatalysts.
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| 3. |
- Terekhina, Irina, et al.
(författare)
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Electrocatalytic Oxidation of Glycerol to Value-Added Compounds on Pd Nanocrystals
- 2023
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Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 6:13, s. 11211-11220
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Tidskriftsartikel (refereegranskat)abstract
- Pd octahedral, rhombic dodecahedral, and cubic nanoparticles (PdOCTA, PdRD, and PdCUBE NPs) were synthesized, characterized, and studied as catalysts for the glycerol electrooxidation reaction (GEOR) in a strongly alkaline medium at 20 and 60 °C. The highest mass activity of 0.050 and 0.183 mA/μgPd was observed on PdOCTA at 20 and 60 °C, respectively, whereas PdCUBE exhibited the highest specific activity of 1.49 and 12.84 mA/cmPd2, respectively. The GEOR products were analyzed by high-performance liquid chromatography (HPLC), and their selectivity and overall glycerol conversion were evaluated at 0.86 V vs RHE. The selectivity toward the three-carbon chain (C3) GEOR products was similar for the different types of catalysts, with PdOCTA and PdCUBE NPs achieving more than 50% selectivity at 20 °C and more than 60% at 60 °C. Glycerate was the overall dominant product for all catalysts, with a selectivity of up to 42%. The glycerol conversion was found to be highest for PdOCTA─21% at 20 °C and 82% at 60 °C, while PdRD was the least active and showed less than 3% conversion at 20 °C and 35% at 60 °C. Based on the GEOR product distribution, a reaction mechanism was proposed.
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| 4. |
- White, Jai, 1991-
(författare)
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From Facets to Flow: The Electrooxidation of Glycerol on Pd-based catalysts
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Glycerol, a by-product of biodiesel refineries, has uses in industries such as cosmetics, food, and pharmaceuticals. However, its usage is small compared to the amount of glycerol produced from biodiesel production. Therefore, there is an opportunity to use glycerol, an important platform chemical, as a cheap feedstock for the synthesis of valuable chemicals. These chemicals can be formed in aqueous media through the glycerol electrooxidation reaction (GEOR) on the anode with hydrogen gas concurrently generated on the cathode. This thesis focuses on the GEOR in alkaline media on Pd and PdNi catalysts. The works compiled here evaluate the GEOR using electrochemical methods such as cyclic voltammetry, galvanostatic polarisation curves, chronoamperometry and chronopotentiometry. Pd and PdNi catalysts were fabricated through chemical synthesis, and electrodeposition onto Ni substrates. Singularly oriented Pd crystal facets were studied, showing those approximating Pd (111) as the most active. Similarly faceted bimetallic PdNi nanoparticles proved significantly more active than pure Pd. Effects of mass transport, studied for Pd/NiRDE and PdNi/NiRDE, indicated performance effects linked to diffusion and underutilisation of thicker catalyst layers. In aerated solutions, industrially relevant current densities were achieved on PdNi/Nifoam in concentrated electrolytes at elevated temperatures for extended periods. The analysis of glycerol oxidation products, formed during steady state measurements, was done using high performance liquid chromatography. The two major products were consistently shown to be glycerate and lactate. This work, covering many aspects of the GEOR, shows that Pd-based catalysts have potential for future industrial application.
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| 5. |
- White, Jai, et al.
(författare)
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Glycerol Electrooxidation at Industrially Relevant Current Densities Using Electrodeposited PdNi/Nifoam Catalysts in Aerated Alkaline Media
- 2023
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 170:8
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Tidskriftsartikel (refereegranskat)abstract
- Through glycerol electrooxidation, we demonstrate the viability of using a PdNi catalyst electrodeposited on Ni foam to facilitate industrially relevant rates of hydrogen generation while concurrently providing valuable organic chemicals as glycerol oxidation products. This electrocatalyst, in a solution of 2 M NaOH and 1 M glycerol at 80 °C, enabled current densities above 2000 mA cm−2 (in a voltammetric sweep) to be obtained in atmospheres of both air and N2. Repeated potential cycling under an aerated atmosphere to these exceptional current densities indicated a high stability of the catalyst. Through steady state polarisation curves, 1000 mA cm−2 was reached below an anodic potential of 0.8 V vs RHE. Chronoamperometry showed glycerate and lactate being the major oxidation products, with increased selectivity for lactate at the expense of glycerate in aerated systems. Aerated atmospheres were demonstrated to consistently increase the apparent Faradaic efficiency to >100%, as determined by the concentration of oxidation products in solution. The excellent performance of PdNi/Ni in aerated solutions suggests that O2 removal from the electrolyte is not needed for an industrial glycerol electrooxidation process, and that combining electrochemical and chemical glycerol oxidation, in the presence of dissolved O2, presents an important process advantage.
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