| 1. |
- Lee, Husileng, et al.
(författare)
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An organic polymer CuPPc-derived copper oxide as a highly efficient electrocatalyst for water oxidation
- 2020
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Ingår i: Chemical Communications. - : ROYAL SOC CHEMISTRY. - 1359-7345 .- 1364-548X. ; 56:26, s. 3797-3800
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we report a novel CuPPc (copper polymeric phthalocyanine)/CF (copper foam) nanoflake material, as precatalyst for the generation of an excellent water oxidation catalyst (WOC). Under optimized conditions, the CuPPc-derived Cu oxide affords a current density of 10 mA cm(-2) under an overpotential (eta) of 287 mV and sustains for at least 50 h in 1.0 M KOH. The strategy presented here is favorable to develop the electrocatalysts for water splitting.
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| 2. |
- Lee, Husileng, et al.
(författare)
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Hierarchical CoS2/Ni3S2/CoNiOx nanorods with favorable stability at 1 A cm(-2) for electrocatalytic water oxidation
- 2019
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Ingår i: Chemical Communications. - : ROYAL SOC CHEMISTRY. - 1359-7345 .- 1364-548X. ; 55:11, s. 1564-1567
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we have reported an easily synthesized CoS2/Ni3S2/CoNiOx water oxidation catalyst with excellent catalytic activity and superior durability. The as-prepared catalyst required overpotential (eta) as low as 256 mV to exhibit a current density of 10 mA cm(-2) in 1.0 M KOH. Remarkably, it sustained a current density of 1 A cm(-2) for one week in 30% KOH solution with only 25 mV increment of eta. Thus, it is a hopeful candidate as a highly-effective water oxidation electrode in practical applications.
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| 3. |
- Wu, Xiujuan, et al.
(författare)
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Hollow Carbon@NiCo2O4 Core-Shell Microspheres for Efficient Electrocatalytic Oxygen Evolution
- 2019
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Ingår i: ENERGY TECHNOLOGY. - : Wiley. - 2194-4288 .- 2194-4296. ; 7:4
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Tidskriftsartikel (refereegranskat)abstract
- Earth-abundant transition metal oxides are considered one of the most promising oxygen evolution reaction (OER) catalysts. However, their intrinsically low electrical conductivity inhibits the fast kinetics for OER. To overcome this drawback, hollow carbon@NiCo2O4 core-shell microspheres (C@NiCo2O4 HSs) are synthesized with enhanced electrocatalytic activity and stability toward OER. The prepared C@NiCo2O4/Ni foam delivers a current density of 10 mA cm(-2) at a small overpotential of 268 mV and exhibits a low Tafel slope of 54 mV dec(-1). The enhanced OER performance is attributed to the enlarged specific surface area induced by the combination effect between the 1D nanosheet structure and the 3D hollow microsphere structure, and the improved electrical conductivity is ascribed to the carbon core support.
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| 4. |
- Wu, Xingqiang, et al.
(författare)
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NiCo/Ni/CuO nanosheets/nanowires on copper foam as an efficient and durable electrocatalyst for oxygen evolution reaction
- 2020
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 45:41, s. 21354-21363
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical water splitting for hydrogen production is a promising solution for the production of renewable and environmentally friendly energy sources, but it is hindered by the sluggish kinetic process of oxygen evolution reaction (OER). Here, a novel hierarchical core-shell nanoarray NiCo/Ni/CuO/CF was synthesized by assembling Ni-Co hydroxide nanosheets directly on the metallic nickel coated CuO nanowires, as a highly efficient electrocatalyst for alkaline OER. This NiCo/Ni/CuO/CF anode exhibited low overpotentials of 246 mV and 286 mV at current densities of 10 mA cm(-2) and 100 mA cm(-2), respectively, and a small Tafel slope of 37.9 mV dec(-1). Moreover, NiCo/Ni/CuO/CF showed robust durability at least 60 h at a current density of 100 mA cm(-2). Detailed investigations verified that the unique nanosheets/nanowires architecture with high conductivity metallic nickel layer can expand the exposure of active sites and accelerate the transport of electrons.
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| 5. |
- Fang, Zhiyong, et al.
(författare)
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Selective Electro-oxidation of Alcohols to the Corresponding Aldehydes in Aqueous Solution via Cu(III) Intermediates from CuO Nanorods
- 2021
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 9:35, s. 11855-11861
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical oxidation using renewable energy is an attractive strategy that provides a sustainable and mild approach for biomass transformation. Herein, the electrocatalytic oxidation of furfuryl alcohol in an aqueous solution was investigated using CuO nanorods. Two kinds of Cu-III intermediates, namely, (CuO2)(-) and (Cu2O6)(6-), were detected on the surface of the working electrode. (Cu2O6)(6-), generated in the potential range of 1.35-1.39 V versus the reversible hydrogen electrode (RHE), induced the oxidation of furfuryl alcohol to furaldehyde with a yield of >= 98%. (CuO2)(-), generated at a potential greater than 1.39 V versus RHE, which led to the oxidation of furfuryl alcohol to 2-furoic acid with a yield of >= 99%. Furthermore, the Cu-III-catalyzed system exhibited a measure of universal applicability, wherein (Cu2O6)(6-) and (CuO2)(-) induced the highly selective electro-oxidation of benzyl alcohol, vanillyl alcohol, and 4-pyridinemethanol to yield the corresponding aldehydes and acids, respectively.
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| 6. |
- Lee, Husileng, et al.
(författare)
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Copper-based homogeneous and heterogeneous catalysts for electrochemical water oxidation
- 2020
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 12:7, s. 4187-4218
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Forskningsöversikt (refereegranskat)abstract
- Water oxidation is currently believed to be the bottleneck in the field of electrochemical water splitting and artificial photosynthesis. Enormous efforts have been devoted toward the exploration of water oxidation catalysts (WOCs), including homogeneous and heterogeneous catalysts. Recently, Cu-based WOCs have been widely developed because of their high abundance, low cost, and biological relevance. However, to the best of our knowledge, no review has been made so far on such types of catalysts. Thus, we have summarized the recent progress made in the development of homogeneous and heterogeneous Cu-based WOCs for electrochemical catalysis. Furthermore, the evaluations of catalytic activity, stability, and mechanism of these catalysts are carefully concluded and highlighted. We believe that this review can summarize the current progress in the field of Cu-based electrochemical WOCs and help in the design of more efficient and stable WOCs.
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| 7. |
- Li, Fusheng, et al.
(författare)
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Dye-sensitized LaFeO3 photocathode for solar-driven H-2 generation
- 2019
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Ingår i: Chemical Communications. - : Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; 55:86, s. 12940-12943
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Tidskriftsartikel (refereegranskat)abstract
- Mesoporous LaFeO3 was used as a p-type visible-light-absorbing semiconductor (VLAS) substrate for light-driven H-2 generation. The successful modification of LaFeO3 with a molecular dye (P1*) and a molecular hydrogen production catalyst (NiP) paved a novel way to construct DS-PEC photocathodes for solar-driven H-2 generation by using VLASs.
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| 8. |
- Li, Fusheng, 1985-, et al.
(författare)
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Electroless Plating of NiFeP Alloy on the Surface of Silicon Photoanode for Efficient Photoelectrochemical Water Oxidation
- 2020
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:10, s. 11479-11488
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Tidskriftsartikel (refereegranskat)abstract
- N- type silicon is a kind of semiconductor with a narrow band gap that has been reported as an outstanding light-harvesting material for photoelectrochemical (PEC) reactions. Decorating a thin catalyst layer on the n-type silicon surface can provide a direct and effective route toward PEC water oxidation. However, most of catalyst immobilization methods for reported n-type silicon photoanodes have been based on energetically demanding, time-consuming, and high-cost processes. Herein, a high-performance NiFeP alloy (NiFeP)-decorated n-type micro-pyramid silicon array (n-Si) photoanode (NiFeP/n-Si) was prepared by a fast and low-cost electroless deposition method for light-driven water oxidation reaction. The saturated photocurrent density of NiFeP/n-Si can reach up to similar to 40 mA cm(-2) and a photocurrent density of 15.5 mA cm(-2) can be achieved at 1.23 V-RHE under light illumination (100 mW cm(-2), AM1.5 filter), which is one of the most promising silicon-based photoanodes to date. The kinetic studies showed that the NiFeP on the silicon photoanodes could significantly decrease the interfacial charge recombination between the n-type silicon surface and electrolyte.
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| 9. |
- Li, Wenlong, et al.
(författare)
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A bio-inspired coordination polymer as outstanding water oxidation catalyst via second coordination sphere engineering
- 2019
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- First-row transition metal-based catalysts have been developed for the oxygen evolution reaction (OER) during the past years, however, such catalysts typically operate at overpotentials (eta) significantly above thermodynamic requirements. Here, we report an iron/ nickel terephthalate coordination polymer on nickel form (NiFeCP/NF) as catalyst for OER, in which both coordinated and uncoordinated carboxylates were maintained after electrolysis. NiFeCP/NF exhibits outstanding electro-catalytic OER activity with a low overpotential of 188 mV at 10 mA cm(-2) in 1.0 KOH, with a small Tafel slope and excellent stability. The pH-independent OER activity of NiFeCP/NF on the reversible hydrogen electrode scale suggests that a concerted proton-coupled electron transfer (c-PET) process is the rate-determining step (RDS) during water oxidation. Deuterium kinetic isotope effects, proton inventory studies and atom-proton-transfer measurements indicate that the uncoordinated carboxylates are serving as the proton transfer relays, with a similar function as amino acid residues in photosystem II (PSII), accelerating the proton-transfer rate.
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| 10. |
- Wang, Xiaoxiao, et al.
(författare)
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Copper Selenide-Derived Copper Oxide Nanoplates as a Durable and Efficient Electrocatalyst for Oxygen Evolution Reaction
- 2020
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Ingår i: Energy Technology. - : Wiley. - 2194-4288 .- 2194-4296. ; 8:7
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Tidskriftsartikel (refereegranskat)abstract
- Earth-abundant transition metal-based nanomaterials play a signi?cant role in oxygen evolution reaction (OER). Among them, copper has attracted signi?cant attention due to its excellent electrocatalytic activity, low price, and abundance. Herein, a nanostructured copper oxide (CuO-A) is generated in situ from a cuprous selenide (Cu2Se) precursor under oxygen evolution reaction conditions. The as-prepared CuO-A/copper foam (CF) electrode delivers a current density of 10 mA cm(-2) at an overpotential of 297 mV with good stability for over 50 h in 1 m KOH solution, which is superior to most recently reported copper-based water oxidation catalysts. The high catalytic performance of CuO-A is mainly attributed to the improved surface area offered by the morphology reconstruction during the in situ transformation process. As a result, it paves a way to synthesize effective and stable transition metal oxide catalysts via the in situ conversion of transition metal chalcogenides for energy conversion and storage applications.
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| 11. |
- Wu, Xiujuan, et al.
(författare)
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A nonheme manganese(IV)-oxo species generated in photocatalytic reaction using water as an oxygen source
- 2015
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 51:19, s. 4013-4016
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Tidskriftsartikel (refereegranskat)abstract
- A nonheme manganese(IV)-oxo complex, [Mn-IV(O)(BQCN)](2+), was generated in the photochemical and chemical oxidation of [Mn-II(BQCN)](2+) with water as an oxygen source, respectively. The photocatalytic oxidation of organic substrates, such as alcohol and sulfide, by [Mn-II(BQCN)](2+) has been demonstrated in both neutral and acidic media.
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| 12. |
- Wu, Xiujuan, et al.
(författare)
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Exploration of electrocatalytic water oxidation properties of NiFe catalysts doped with nonmetallic elements (P, S, Se)
- 2021
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 46:79, s. 38992-39002
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Tidskriftsartikel (refereegranskat)abstract
- The introduction of non-metallic atoms (P, S, Se) has emerged as an effective way to improve the catalytic activity of transition metal based layered double hydroxides (LDHs) for oxygen evolution reaction. However, objective comparisons of the performance of heteroelement-doped catalysts are complicated by the lack of standardization both in the electrochemical tests and physicochemical analysis. Herein, we use a unified protocol for evaluating the catalytic activities of heteroelement-doped NiFe-LDHs and explore the reasons for the differences in their catalytic performance. Some regular results are found from comparing the properties of the heteroelement-doped catalysts: (1) the introduction of P/S/Se can optimize the redox behaviors of Ni species, which is conducive to regulating adsorption energy of intermediates and the formation of high-valent active sites; (2) the specific area of catalysts was expanded after heteroelements doping, ensuring a more favorable structure for heterogeneous catalysis; (3) All P/S/Se-doped catalysts showed better activities when compared to the original NiFe LDHs in alkaline solutions, and the catalysts doped with S showed the best performance (Se < P < S).
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| 13. |
- Wu, Xiujuan, et al.
(författare)
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Hierarchically Structured FeNiOxHy Electrocatalyst Formed by In Situ Transformation of Metal Phosphate for Efficient Oxygen Evolution Reaction
- 2018
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Ingår i: ChemSusChem. - : WILEY-V C H VERLAG GMBH. - 1864-5631 .- 1864-564X. ; 11:11, s. 1761-1767
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Tidskriftsartikel (refereegranskat)abstract
- A simple and low-cost fabrication method is needed to obtain effective and robust heterogeneous catalysts for the oxygen evolution reaction (OER). In this study, an electrocatalyst FeNiOxHy with a hierarchical structure is synthesized on nickel foam by a simple fabrication method through anion exchange from a metal phosphate to a metal hydroxide. The as-fabricated FeNiOxHy electrode requires overpotentials of 206 and 234 mV to deliver current densities of 10 and 50 mAcm(-2), respectively. The catalytic performance of FeNiOxHy is superior to that of most previously reported FeNi-based catalysts, including NiFe layered double hydroxide. The catalyst also shows good long-term durability at a current density of 50 mA cm(-2) over 50 h with no activity decay under 1 m KOH. By comparison to the directly electrodeposited FeNi hydroxide in morphology and electrochemical properties, the improved activity of the catalyst could be mainly attributed to an enhancement of its intrinsic activity, which was caused by the anion exchange of phosphate to (oxy)hydroxide. Further studies by cyclic voltammetry indicated a stronger interaction between Ni and Fe from the negative shift of the oxidation peak of Ni2+/Ni3+ in comparison with reported FeNiOxHy, which promoted the generation of active Ni3+ species more easily. This work may provide a new approach to the simple preparation of effective and robust OER catalysts by anion exchange.
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| 14. |
- Wu, Xiujuan, et al.
(författare)
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Metalloid Te-Doped Fe-Based Catalysts Applied for Electrochemical Water Oxidation
- 2021
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Ingår i: CHEMISTRYSELECT. - : Wiley. - 2365-6549. ; 6:24, s. 6154-6158
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Tidskriftsartikel (refereegranskat)abstract
- Metal telluride nanocatalysts have been widely used in the catalytic reactions. However, there are few examples of electrocatalytic water oxidation with metal telluride as catalysts, especially Fe-based telluride, to the best of our knowledge, has not yet been reported. In this work, the Te-doped Fe-based catalysts (FeTex) with crystalline and amorphous nanosheet structures have been successfully synthesized by chemical vapor deposition (CVD) as well as electrodeposition (ED) on the iron foam (IF), where the latter exhibited more remarkable electrocatalytic performance towards the oxygen evolution reaction (OER) in the alkaline electrolyte, requiring the overpotential (eta) of only 264.4 mV to reach a current density of 10 mA cm(-2) with a Tafel slope of 54.2 mV dec(-1). The electrochemical study confirmed that the residual Te in ED-FeTex does play a role in promoting the catalytic activity for the electrocatalytic water oxidation.
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| 15. |
- Yang, Hao, et al.
(författare)
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Improving the performance of water splitting electrodes by composite plating with nano-SiO2
- 2018
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Ingår i: Electrochimica Acta. - : Pergamon Press. - 0013-4686 .- 1873-3859. ; 281, s. 60-68
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Tidskriftsartikel (refereegranskat)abstract
- The electrochemical splitting of water requires efficient functional electrodes. Herein, we report the fabrication of electrocatalyst consisted of an electrodeposited NiFeP alloy film which was composite plated with nano-SiO2 on nickel foam. The structure and morphology of the film were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the surface area of this NiFeP-SiO2 co-deposition alloy film can be significantly increased after electrochemical etching in a KOH solution. The water splitting properties of the alloy film were evaluated using electrochemistry. By using the NiFeP-SiO2/NF(Etched) as a bifunctional electrode, total water splitting has been demonstrated in a two-electrode cell with a current density of 10 mAcm(-2) at an applied voltage of 1.57 V, which exhibited enhanced water splitting activity in comparison to the analogue cell using the pristine NiFeP/NF electrode.
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| 16. |
- Ye, Qilun, et al.
(författare)
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Urchin-Like Cobalt-Copper (Hydr)oxides as an Efficient Water Oxidation Electrocatalyst
- 2020
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Ingår i: ChemPlusChem. - : Wiley. - 2192-6506. ; 85:6, s. 1339-1346
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Tidskriftsartikel (refereegranskat)abstract
- The development of e & xfb03;cient and low-cost oxygen evolution reaction (OER) catalysts is essential for the generation of clean hydrogen energy from water splitting. Herein, a novel hierarchical urchin-like cobalt-copper (hydr)oxide in situ grown on copper foam (CoCuOxHy(S)/CF) was synthesized through the electrochemical transformation of cobalt-copper sulfides (Co9S8-Cu1.81S) via anodization process. This CoCuOxHy(S)/CF anode exhibited a low overpotential (eta) of 274 mV at a current density of 100 mA cm(-2)with a robust durability over a period of 40 h when operated at 10 mA cm(-2). Further investigations imply that the unique nanowires aggregated urchin-like structure of CoCuOxHy(S) derived from the in situ anion exchange process could facilitate the exposure of active sites and accelerate electron transfer. More importantly, the incorporation of copper resulted in an electronic delocalization around the cobalt species, which contributed to reach a high-valent catalytically active cobalt species and further improved the OER performance.
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| 17. |
- Zhao, Ziqi, et al.
(författare)
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Molecular Engineering of Photocathodes based on Polythiophene Organic Semiconductors for Photoelectrochemical Hydrogen Generation
- 2021
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 13:34, s. 40602-40611
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Tidskriftsartikel (refereegranskat)abstract
- Organic semiconductors provide significant potentials for the construction of photoelectrochemical (PEC) cells for solar hydrogen production because of their highly tunable properties. Herein, on carbon fiber paper (CFP) surface, pyridyl (Py), and 4,4'-bipyridin-1-ium (Py-2(+)) groups were introduced into polythiophene (pTH) semiconductor by electrochemical copolymerization, respectively. After assembly with the Co(dmgBF(2))(2) type catalyst (CoB, dmgBF(2) = difluoroboryldimethylglyoximate), the CoB@Py-2(+)-pTH/CFP photocathode displayed nearly twice the photocurrent enhancement (550 mu A cm(-2) at 0.15 V vs reversible hydrogen electrode, RHE) comparing to that generated by the CoB@Py-pTH/CFP photocathode (290 mu A cm(-2) at 0.15 V vs RHE) for light-driven H-2 generation under AM 1.5 solar illumination. Investigation of the mechanism revealed that the introduction of the positively charged pyridinium groups could improve the intrinsic Co(dmgBF(2))(2) catalyst activity for the H-2 generation reaction. Meanwhile, the positively charged pyridinium groups serve as p-type dopants to increase the semiconductor bulk charge transfer rate and act as electron transfer mediators to promote the interfacial charge transfer kinetics between the catalyst and the pTH-based organic semiconductor.
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