Editorial

5 pages, 222 KiB

Open AccessEditorial

by Oleg V. Levin

Catalysts 2023, 13(12), 1484; https://0-doi-org.brum.beds.ac.uk/10.3390/catal13121484 - 30 Nov 2023

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Catalysis stands as a fundamental driver in the energy landscape, influencing processes across the entire energy life cycle [...] Full article

(This article belongs to the Special Issue Catalysts in Energy Applications)

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12 pages, 2931 KiB

Open AccessArticle

Enhanced Electrocatalytic Activity of Cobalt-Doped Ceria Embedded on Nitrogen, Sulfur-Doped Reduced Graphene Oxide as an Electrocatalyst for Oxygen Reduction Reaction

by Manickam Sridharan, Thandavarayan Maiyalagan, Gasidit Panomsuwan and Ratchatee Techapiesancharoenkij

Catalysts 2022, 12(1), 6; https://0-doi-org.brum.beds.ac.uk/10.3390/catal12010006 - 22 Dec 2021

Cited by 9 | Viewed by 2825

Abstract

N, S-doped rGO was successfully synthesized and embedded Co-doped CeO₂ via hydrothermal synthesis. The crystal structure, surface morphology and elemental composition of the prepared catalyst were studied by XRD, Raman spectra, SEM, TEM and XPS analyses. The synthesized electrocatalyst exhibits high onset [...] Read more.

N, S-doped rGO was successfully synthesized and embedded Co-doped CeO₂ via hydrothermal synthesis. The crystal structure, surface morphology and elemental composition of the prepared catalyst were studied by XRD, Raman spectra, SEM, TEM and XPS analyses. The synthesized electrocatalyst exhibits high onset and halfwave potential during the ORR. This result shows that a combination of N- and S-doped rGO and Co-doped CeO₂ leads to a synergistic effect in catalyzing the ORR in alkaline media. Co–CeO₂/N, S–rGO displays enhanced ORR performance compared to bare CeO₂. The superior stability of the prepared catalyst implies its potential applications beyond fuel cells and metal–air batteries. Full article

(This article belongs to the Special Issue Catalysts in Energy Applications)

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9 pages, 1902 KiB

Open AccessFeature PaperArticle

Inversion of the Photogalvanic Effect of Conductive Polymers by Porphyrin Dopants

by Alexey A. Petrov, Daniil A. Lukyanov, Oleg A. Kopytko, Julia V. Novoselova, Elena V. Alekseeva and Oleg V. Levin

Catalysts 2021, 11(6), 729; https://0-doi-org.brum.beds.ac.uk/10.3390/catal11060729 - 12 Jun 2021

Cited by 6 | Viewed by 2210

Abstract

Conductive polymers are widely used as active and auxiliary materials for organic photovoltaic cells due to their easily tunable properties, high electronic conductivity, and light absorption. Several conductive polymers show the cathodic photogalvanic effect in pristine state. Recently, photoelectrochemical oxygen reduction has been [...] Read more.

Conductive polymers are widely used as active and auxiliary materials for organic photovoltaic cells due to their easily tunable properties, high electronic conductivity, and light absorption. Several conductive polymers show the cathodic photogalvanic effect in pristine state. Recently, photoelectrochemical oxygen reduction has been demonstrated for nickel complexes of Salen-type ligands. Herein, we report an unexpected inversion of the photogalvanic effect caused by doping of the NiSalen polymers with anionic porphyrins. The observed effect was studied by means of UV-Vis spectroscopy, cyclic voltammetry and chopped light chronoamperometry. While pristine NiSalens exhibit cathodic photopolarization, doping with porphyrins inverts the polarization. As a result, photoelectrochemical oxidation of the ascorbate proceeds smoothly on the NiSalen electrode doped with zinc porphyrins. The highest photocurrents were observed on NiSalen polymer with o-phenylene imine bridge, doped with anionic zinc porphyrin. Assuming this, porphyrin serves both as a catalytic center for the oxidation of ascorbate and an internal electron donor, facilitating the photoinduced charge transport and anodic depolarization. Full article

(This article belongs to the Special Issue Catalysts in Energy Applications)

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12 pages, 3007 KiB

Open AccessArticle

Theoretical Insights into the Hydrogen Evolution Reaction on the Ni₃N Electrocatalyst

by Russell W. Cross, Sachin R. Rondiya and Nelson Y. Dzade

Catalysts 2021, 11(6), 716; https://0-doi-org.brum.beds.ac.uk/10.3390/catal11060716 - 08 Jun 2021

Cited by 8 | Viewed by 2852

Abstract

Ni-based catalysts are attractive alternatives to noble metal electrocatalysts for the hydrogen evolution reaction (HER). Herein, we present a dispersion-corrected density functional theory (DFT-D3) insight into HER activity on the (111), (110), (001), and (100) surfaces of metallic nickel nitride (Ni₃N). [...] Read more.

Ni-based catalysts are attractive alternatives to noble metal electrocatalysts for the hydrogen evolution reaction (HER). Herein, we present a dispersion-corrected density functional theory (DFT-D3) insight into HER activity on the (111), (110), (001), and (100) surfaces of metallic nickel nitride (Ni₃N). A combination of water and hydrogen adsorption was used to model the electrode interactions within the water splitting cell. Surface energies were used to characterise the stabilities of the Ni₃N surfaces, along with adsorption energies to determine preferable sites for adsorbate interactions. The surface stability order was found to be (111) < (100) < (001) < (110), with calculated surface energies of 2.10, 2.27, 2.37, and 2.38 Jm⁻², respectively. Water adsorption was found to be exothermic at all surfaces, and most favourable on the (111) surface, with E_ads = −0.79 eV, followed closely by the (100), (110), and (001) surfaces at −0.66, −0.65, and −0.56 eV, respectively. The water splitting reaction was investigated at each surface to determine the rate determining Volmer step and the activation energies (E_a) for alkaline HER, which has thus far not been studied in detail for Ni₃N. The E_a values for water splitting on the Ni₃N surfaces were predicted in the order (001) < (111) < (110) < (100), which were 0.17, 0.73, 1.11, and 1.60 eV, respectively, overall showing the (001) surface to be most active for the Volmer step of water dissociation. Active hydrogen adsorption sites are also presented for acidic HER, evaluated through the ΔG_H descriptor. The (110) surface was shown to have an extremely active Ni–N bridging site with ΔG_H = −0.05 eV. Full article

(This article belongs to the Special Issue Catalysts in Energy Applications)

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12 pages, 9141 KiB

Open AccessArticle

Activating the FeS (001) Surface for CO₂ Adsorption and Reduction through the Formation of Sulfur Vacancies: A DFT-D3 Study

by Nelson Y. Dzade and Nora H. de Leeuw

Catalysts 2021, 11(1), 127; https://0-doi-org.brum.beds.ac.uk/10.3390/catal11010127 - 15 Jan 2021

Cited by 16 | Viewed by 3304

Abstract

As a promising material for heterogeneous catalytic applications, layered iron (II) monosulfide (FeS) contains active edges and an inert basal (001) plane. Activating the basal (001) plane could improve the catalytic performance of the FeS material towards CO₂ activation and reduction reactions. [...] Read more.

As a promising material for heterogeneous catalytic applications, layered iron (II) monosulfide (FeS) contains active edges and an inert basal (001) plane. Activating the basal (001) plane could improve the catalytic performance of the FeS material towards CO₂ activation and reduction reactions. Herein, we report dispersion-corrected density functional theory (DFT-D3) calculations of the adsorption of CO₂ and the elementary steps involved in its reduction through the reverse water-gas shift reaction on a defective FeS (001) surface containing sulfur vacancies. The exposed Fe sites resulting from the creation of sulfur vacancies are shown to act as highly active sites for CO₂ activation and reduction. Based on the calculated adsorption energies, we show that the CO₂ molecules will outcompete H₂O and H₂ molecules for the exposed active Fe sites if all three molecules are present on or near the surface. The CO₂ molecule is found to weakly physisorb (−0.20 eV) compared to the sulfur-deficient (001) surface where it adsorbs much strongly, releasing adsorption energy of −1.78 and −1.83 eV at the defective FeS (001) surface containing a single and double sulfur vacancy, respectively. The CO₂ molecule gained significant charge from the interacting surface Fe ions at the defective surface upon adsorption, which resulted in activation of the C–O bonds confirmed via vibrational frequency analyses. The reaction and activation energy barriers of the elementary steps involved in the CO₂ hydrogenation reactions to form CO and H₂O species are also unraveled. Full article

(This article belongs to the Special Issue Catalysts in Energy Applications)

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17 pages, 15742 KiB

Open AccessArticle

Electrooxidation of Urea in Alkaline Solution Using Nickel Hydroxide Activated Carbon Paper Electrodeposited from DMSO Solution

by Saba A. Aladeemy, Abdullah M. Al-Mayouf, Maged N. Shaddad, Mabrook S. Amer, Nawier K. Almutairi, Mohamed A. Ghanem, Nouf H. Alotaibi and Prabhakarn Arunachalam

Catalysts 2021, 11(1), 102; https://0-doi-org.brum.beds.ac.uk/10.3390/catal11010102 - 13 Jan 2021

Cited by 10 | Viewed by 3937

Abstract

Electrooxidation of urea plays a substantial role in the elimination of urea-containing wastewater and industrial urea. Here, we report the electrodeposition of nickel hydroxide catalyst on commercial carbon paper (CP) electrodes from dimethyl sulphoxide solvent (Ni(OH)₂-DMSO/CP) for urea electrooxidation under alkaline [...] Read more.

Electrooxidation of urea plays a substantial role in the elimination of urea-containing wastewater and industrial urea. Here, we report the electrodeposition of nickel hydroxide catalyst on commercial carbon paper (CP) electrodes from dimethyl sulphoxide solvent (Ni(OH)₂-DMSO/CP) for urea electrooxidation under alkaline conditions. The physicochemical features of Ni(OH)₂-DMSO/CP catalysts using scanning electron microscopy and X-ray photoelectron spectroscopy revealed that the Ni(OH)₂-DMSO/CP catalyst shows nanoparticle features, with loading of <1 wt%. The cyclic voltammetry and electrochemical impedance spectroscopy revealed that the Ni(OH)₂-DMSO/CP electrode has a urea oxidation onset potential of 0.33 V vs. Ag/AgCl and superior electrocatalytic performance, which is a more than 2-fold higher activity in comparison with the counterpart Ni(OH)₂ catalyst prepared from the aqueous electrolyte. As expected, the enhancement in electrocatalytic activity towards urea was associated with the superficial enrichment in the electrochemically active surface area of the Ni(OH)₂-DMSO/CP electrodes. The results might be a promising way to activate commercial carbon paper with efficient transition metal electrocatalysts, for urea electrooxidation uses in sustainable energy systems, and for relieving water contamination. Full article

(This article belongs to the Special Issue Catalysts in Energy Applications)

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17 pages, 4566 KiB

Open AccessArticle

Solid-State Ball-Milling of Co₃O₄ Nano/Microspheres and Carbon Black Endorsed LaMnO₃ Perovskite Catalyst for Bifunctional Oxygen Electrocatalysis

by Chelladurai Karuppiah, Balamurugan Thirumalraj, Srinivasan Alagar, Shakkthivel Piraman, Ying-Jeng Jame Li and Chun-Chen Yang

Catalysts 2021, 11(1), 76; https://0-doi-org.brum.beds.ac.uk/10.3390/catal11010076 - 07 Jan 2021

Cited by 23 | Viewed by 4212

Abstract

Developing a highly stable and non-precious, low-cost, bifunctional electrocatalyst is essential for energy storage and energy conversion devices due to the increasing demand from the consumers. Therefore, the fabrication of a bifunctional electrocatalyst is an emerging focus for the promotion and dissemination of [...] Read more.

Developing a highly stable and non-precious, low-cost, bifunctional electrocatalyst is essential for energy storage and energy conversion devices due to the increasing demand from the consumers. Therefore, the fabrication of a bifunctional electrocatalyst is an emerging focus for the promotion and dissemination of energy storage/conversion devices. Spinel and perovskite transition metal oxides have been widely explored as efficient bifunctional electrocatalysts to replace the noble metals in fuel cell and metal-air batteries. In this work, we developed a bifunctional catalyst for oxygen reduction and oxygen evolution reaction (ORR/OER) study using the mechanochemical route coupling of cobalt oxide nano/microspheres and carbon black particles incorporated lanthanum manganite perovskite (LaMnO₃@C-Co₃O₄) composite. It was synthesized through a simple and less-time consuming solid-state ball-milling method. The synthesized LaMnO₃@C-Co₃O₄ composite was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller (BET) analysis, X-ray diffraction spectroscopy, and micro-Raman spectroscopy techniques. The electrocatalysis results showed excellent electrochemical activity towards ORR/OER kinetics using LaMnO₃@C-Co₃O₄ catalyst, as compared with Pt/C, bare LaMnO₃@C, and LaMnO₃@C-RuO₂ catalysts. The observed results suggested that the newly developed LaMnO₃@C-Co₃O₄ electrocatalyst can be used as a potential candidate for air-cathodes in fuel cell and metal-air batteries. Full article

(This article belongs to the Special Issue Catalysts in Energy Applications)

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10 pages, 3339 KiB

Open AccessArticle

Benchmarking Perovskite Electrocatalysts’ OER Activity as Candidate Materials for Industrial Alkaline Water Electrolysis

by DJ Donn Matienzo, Tuğçe Kutlusoy, Spyridon Divanis, Chiara Di Bari and Emanuele Instuli

Catalysts 2020, 10(12), 1387; https://0-doi-org.brum.beds.ac.uk/10.3390/catal10121387 - 28 Nov 2020

Cited by 15 | Viewed by 4767

Abstract

The selection and evaluation of electrocatalysts as candidate materials for industrial alkaline water electrolysis is fundamental in the development of promising energy storage and sustainable fuels for future energy infrastructure. However, the oxygen evolution reaction (OER) activities of various electrocatalysts already reported in [...] Read more.

The selection and evaluation of electrocatalysts as candidate materials for industrial alkaline water electrolysis is fundamental in the development of promising energy storage and sustainable fuels for future energy infrastructure. However, the oxygen evolution reaction (OER) activities of various electrocatalysts already reported in previous studies are not standardized. This work reports on the use of perovskite materials (LaFeO₃, LaCoO₃, LaNiO₃, PrCoO₃, Pr_0.8Sr_0.2CoO₃, and Pr_0.8Ba_0.2CoO₃) as OER electrocatalysts for alkaline water electrolysis. A facile co-precipitation technique with subsequent thermal annealing (at 700 °C in air) was performed. Industrial requirements and criteria (cost and ease of scaling up) were well-considered for the selection of the materials. The highest OER activity was observed in LaNiO₃ among the La-based perovskites, and in Pr_0.8Sr_0.2CoO₃ among the Pr-based perovskites. Moreover, the formation of double perovskites (Pr_0.8Sr_0.2CoO₃ and Pr_0.8Ba_0.2CoO₃) improved the OER activity of PrCoO₃. This work highlights that the simple characterization and electrochemical tests performed are considered the initial step in evaluating candidate catalyst materials to be used for industrial alkaline water electrolysis. Full article

(This article belongs to the Special Issue Catalysts in Energy Applications)

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13 pages, 7372 KiB

Open AccessArticle

MOF-Derived CuPt/NC Electrocatalyst for Oxygen Reduction Reaction

by Rehan Anwar, Naseem Iqbal, Saadia Hanif, Tayyaba Noor, Xuan Shi, Neelam Zaman, Daarain Haider, Syed Aun M. Rizvi and A. M. Kannan

Catalysts 2020, 10(7), 799; https://0-doi-org.brum.beds.ac.uk/10.3390/catal10070799 - 17 Jul 2020

Cited by 24 | Viewed by 3882

Abstract

Metal-organic frameworks (MOFs) have been at the center stage of material science in the recent past because of their structural properties and wide applications in catalysis. MOFs have also been used as hard templates for the preparation of catalysts. In this study, highly [...] Read more.

Metal-organic frameworks (MOFs) have been at the center stage of material science in the recent past because of their structural properties and wide applications in catalysis. MOFs have also been used as hard templates for the preparation of catalysts. In this study, highly active CuPt/NC electrocatalyst was synthesized by pyrolyzing Cu-tpa MOF along with Pt precursor under flowing Ar-H₂ atmosphere. The catalyst was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD). Rotating disk electrode study was performed to determine the oxygen reduction reaction (ORR) activity for CuPt/NC in 0.1 M HClO₄ at different revolutions per minute (400, 800, 1200, and 1600) and it was also compared with commercial Pt/C catalyst. Further the ORR performance was evaluated by K-L plots and Tafel slope. CuPt/NC shows excellent ORR performance with onset potential of 0.9 V (vs. RHE), which is comparable with commercial Pt/C. The ORR activity of CuPt/NC is demonstrated as an efficient electrocatalyst for fuel cell. Full article

(This article belongs to the Special Issue Catalysts in Energy Applications)

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14 pages, 2649 KiB

Open AccessFeature PaperArticle

Bimetallic Cu/Pt Oxygen Reduction Reaction Catalyst for Fuel Cells Cathode Materials

by Elena Alekseeva, Tatyana Stelmashuk, Stepan Danilov, Peixia Yang and Oleg Levin

Catalysts 2020, 10(6), 667; https://0-doi-org.brum.beds.ac.uk/10.3390/catal10060667 - 13 Jun 2020

Cited by 12 | Viewed by 3800

Abstract

The oxygen reduction reaction (ORR) is a key process for the operation of fuel cells. To accelerate the sluggish kinetics of ORR, a wide range of catalysts have been proposed and tested. In this work, a nano-dispersed copper-impregnated platinum catalyst prepared by electrodeposition [...] Read more.

The oxygen reduction reaction (ORR) is a key process for the operation of fuel cells. To accelerate the sluggish kinetics of ORR, a wide range of catalysts have been proposed and tested. In this work, a nano-dispersed copper-impregnated platinum catalyst prepared by electrodeposition of platinum on a poly[Cu(Salen)] template followed by polymer destruction is described. In addition to the high activity of the thus prepared catalyst in the oxygen reduction reaction surpassing that of both polycrystalline platinum catalyst and the commercial carbon-platinum catalyst (“E-TEK”), it showed remarkable tolerance to the presence of methanol in solution. Full article

(This article belongs to the Special Issue Catalysts in Energy Applications)

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