Publications
58 results found
Jerez S, Pedersen A, Ventura M, et al., 2024, Fe[sbnd]N doped carbon materials from oily sludge as electrocatalysts for alkaline oxygen reduction reaction, Electrochimica Acta, Vol: 483, ISSN: 0013-4686
Alkaline oxygen reduction reaction (ORR) presents an important role for energy conversion technologies and requires the development of an efficient electrocatalyst. Pt-based catalysts provide suitable activity; however, Pt production accessibility and high costs create hurdles to their commercial implementation. Fe coordinated within N-doped carbon materials (Fe[sbnd]N[sbnd]C) are a promising alternative due to their high ORR catalytic activity, although the currently commercially available Fe[sbnd]N[sbnd]C materials rely on harsh synthetic protocols which can lead to increased environmental impacts. In this work we target this issue by taking advantage of an oily sludge waste currently generated in refineries to synthesize Fe[sbnd]N[sbnd]C materials, thus, avoiding the environmental impact caused by the management of this waste. The solid particles within oily sludge, which present a high concentration of C and Fe, were combined by different nitrogen sources and pyrolyzed at high temperatures. The prepared materials present a hierarchical pore structure with surface areas up to 547 m2 g−1. X-ray photoelectron spectroscopy analysis found that the impregnation of N using phenanthroline promotes the formation of pyridinic-N structures, which enhances the ORR performance compared to melamine doping. Additional doping of Fe with phenanthroline results in an ORR mass activity of 1.23 ± 0.04 A gFeNC−1 at 0.9 VRHE, iR-free in a rotating disc electrode (0.1 M KOH). This catalyst also shows a lower relative loss in activity at 0.9 VRHE after 8000 cycles in O2-saturated conditions compared to a commercial FeNC catalyst, PMF D14401, (−63.5 vs −69 %, respectively), demonstrating promise as a cheap and simple route to Fe[sbnd]N[sbnd]C catalysts for alkaline ORR.
Mazzoli L, Pedersen A, Kellner S, et al., 2024, Inducing porosity in xylose-derived FeNC electrocatalysts for alkaline oxygen reduction, Green Chemistry, Vol: 26, Pages: 3271-3280, ISSN: 1463-9262
Iron-nitrogen-carbon (FeNC) electrocatalysts are emerging as a low-cost alternative to Pt-based materials for electrochemical oxygen reduction at the cathode of alkaline exchange membrane hydrogen fuel cells. The valorisation of waste biomass is a sustainable pathway that could allow the large-scale production of such catalysts. By means of hydrothermal carbonization (HTC), a biomass-derived carbohydrate can be converted into a carbonaceous framework, however, the electrocatalytic performance of the metal-nitrogen-carbon electrocatalysts prepared through HTC is suboptimal owing to the lack of microporosity in the highly crosslinked carbon frameworks. In this work, we address this issue by adding polystyrene sulfonate (kayexalate) in the HTC of xylose. Kayexalate's negative charges mitigate particle aggregation, resulting in smaller carbon-based particles, with the O2 activation leading to a four-fold increase in specific surface area (127 vs. 478 m2 g−1). Subsequent high-temperature pyrolysis in the presence of an N and Fe source leads to an active FeNC. This produces a corresponding increase in the electrocatalytic activity for the oxygen reduction in alkaline media in a rotating disk electrode (1.45 vs. 14.3 A g−1 at 0.8 V vs. RHE) and in a gas diffusion electrode at high current densities (≥2 A cm−2). The sustainable character of the reported catalyst as well as the high electrocatalytic activity at industrially relevant current densities provides a pathway to catalyst design for low-cost cathodes in alkaline exchange membrane fuel cells.
Hongrutai N, Sarma SC, Zhou Y, et al., 2024, Sequential deposition of FeNC-Cu tandem CO<inf>2</inf> reduction electrocatalysts towards the low overpotential production of C<inf>2+</inf> alcohols, JPhys Materials, Vol: 7
Tandem CO2 reduction electrocatalysts that combine a material that selectively produces CO with Cu are capable of producing hydrocarbons at low overpotentials and high selectivity. However, controlling the spatial distribution and the catalytic activity of the CO-making catalyst remains a challenge. In this work, a novel tandem electrocatalyst that overcomes limitations of simple Cu catalysts, namely selectivity and efficiency at low overpotential, is presented. The tandem electrocatalysts are prepared through a sequential spray coating protocol, using a single atom Fe in N-doped C (FeNC) as the selective CO-producing catalyst and commercial Cu nanopowder. The high faradaic efficiency towards CO of FeNC (99% observed at −0.60 V vs. RHE) provides a high CO coverage to the Cu particles, leading to reduced hydrogen evolution and the selective formation of ethanol and n-propanol at a much low overpotential than that of bare Cu.
Pedersen A, Bagger A, Barrio J, et al., 2023, Atomic metal coordinated to nitrogen-doped carbon electrocatalysts for proton exchange membrane fuel cells: a perspective on progress, pitfalls and prospectives., J Mater Chem A Mater, Vol: 11, Pages: 23211-23222, ISSN: 2050-7488
Proton exchange membrane fuel cells require reduced construction costs to improve commercial viability, which can be fueled by elimination of platinum as the O2 reduction electrocatalyst. The past 10 years has seen significant developments in synthesis, characterisation, and electrocatalytic performance of the most promising alternative electrocatalyst; single metal atoms coordinated to nitrogen-doped carbon (M-N-C). In this Perspective we recap some of the important achievements of M-N-Cs in the last decade, as well as discussing current knowledge gaps and future research directions for the community. We provide a new outlook on M-N-C stability and atomistic understanding with a set of original density functional theory simulations.
Barrio J, Li J, Shalom M, 2023, Carbon Nitrides from Supramolecular Crystals: From Single Atoms to Heterojunctions and Advanced Photoelectrodes, CHEMISTRY-A EUROPEAN JOURNAL, ISSN: 0947-6539
Sarma SC, Barrio J, Bagger A, et al., 2023, Reaching the fundamental limitation in CO2 reduction to CO with single atom catalysts, Advanced Functional Materials, Vol: 33, ISSN: 1616-301X
The electrochemical CO2 reduction reaction (CO2RR) to value-added chemicals with renewable electricity is a promising method to decarbonize parts of the chemical industry. Recently, single metal atoms in nitrogen-doped carbon (MNC) have emerged as potential electrocatalysts for CO2RR to CO with high activity and faradaic efficiency, although the reaction limitation for CO2RR to CO is unclear. To understand the comparison of intrinsic activity of different MNCs, two catalysts are synthesized through a decoupled two-step synthesis approach of high temperature pyrolysis and low temperature metalation (Fe or Ni). The highly meso-porous structure results in the highest reported electrochemical active site utilization based on in situ nitrite stripping; up to 59±6% for NiNC. Ex situ X-ray absorption spectroscopy (XAS) confirms the penta-coordinated nature of the active sites. The catalysts are amongst the most active in the literature for CO2 reduction to CO. The density functional theory calculations (DFT) show that their binding to the reaction intermediates approximates to that of Au surfaces. However, it is found that the turnover frequencies (TOFs) of the most active catalysts for CO evolution converge, suggesting a fundamental ceiling to the catalytic rates.
Li J, Barrio J, Fang Y, et al., 2023, Elucidating the Effect of Crystallinity on the Photoactivity in Poly(heptazine imides), ENERGY & FUELS, ISSN: 0887-0624
Mukadam Z, Liu S, Pedersen A, et al., 2023, Furfural electrovalorisation using single-atom molecular catalysts, ENERGY & ENVIRONMENTAL SCIENCE, Vol: 16, Pages: 2934-2944, ISSN: 1754-5692
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- Citations: 4
Barrio J, Pedersen A, Sarma SC, et al., 2023, FeNC Oxygen Reduction Electrocatalyst with High Utilization Penta-Coordinated Sites, ADVANCED MATERIALS, Vol: 35, ISSN: 0935-9648
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- Citations: 7
Westhead O, Barrio J, Bagger A, et al., 2023, Near ambient N<sub>2</sub> fixation on solid electrodes versus enzymes and homogeneous catalysts (vol 7, pg 184, 2023), NATURE REVIEWS CHEMISTRY, Vol: 7, Pages: 225-225
Westhead O, Barrio J, Bagger A, et al., 2023, Near ambient N2 fixation on solid electrodes versus enzymes and homogeneous catalysts, Nature Reviews Chemistry, Vol: 7, Pages: 184-201, ISSN: 2397-3358
The Mo/Fe nitrogenase enzyme is unique in its ability to efficiently reduce dinitrogen to ammonia at atmospheric pressures and room temperature. Should an artificial electrolytic device achieve the same feat, it would revolutionise fertilizers and even provide an energy dense, truly carbon-free fuel. This Review provides a coherent comparison of recent progress made in dinitrogen fixation on (i) solid electrodes, (ii) homogeneous catalysts and (iii) nitrogenases. Specific emphasis is placed on systems for which there is unequivocal evidence that dinitrogen reduction has taken place. By establishing the cross-cutting themes and synergies between these systems, we identify viable avenues for future research.
Suarez-Blas F, Li J, Alonso-Navarro MJ, et al., 2023, Naphthalimide-Based 3D Organic Semiconductors: Synthesis and Application as Photo-Electrocatalysts for Organic Dyes Degradation and Water Splitting, ADVANCED SUSTAINABLE SYSTEMS, Vol: 7, ISSN: 2366-7486
Ng KL, Maciejewska BM, Qin L, et al., 2022, Direct Evidence of the Exfoliation Efficiency and Graphene Dispersibility of Green Solvents toward Sustainable Graphene Production, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN: 2168-0485
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- Citations: 6
Barrio J, Pedersen A, Favero S, et al., 2022, Bioinspired and Bioderived Aqueous Electrocatalysis, CHEMICAL REVIEWS, ISSN: 0009-2665
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- Citations: 9
Li J, Dor S, Barrio J, et al., 2022, Efficient Water Cleaning by Self-standing Carbon Nitride Films Derived from Supramolecular Hydrogels, CHEMISTRY-A EUROPEAN JOURNAL, Vol: 28, ISSN: 0947-6539
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- Citations: 2
Li AY, Pedersen A, Feng J, et al., 2022, From haemoglobin to single-site hydrogenation catalyst, Green Chemistry, Vol: 24, Pages: 7574-7583, ISSN: 1463-9262
Iron-based single-site catalysts hold immense potential for achieving highly selective chemical processes, with the added advantage of iron being an earth-abundant metal. They are widely explored in electrocatalysis for oxygen reduction and display promising catalytic activity for organic transformations. In particular, FeNx@C catalysts are active for the reduction of nitroarene into aromatic amines. Yet, they are difficult to mass-produce, and most preparation methods fail to avoid single site aggregation. Here we prepared FeNx@C catalysts from bio-derived compounds, xylose and haemoglobin, in a simple two-step process. Since haemoglobin naturally contains FeNx single-sites, we successfully repurposed them into hydrogenation catalytic centers and avoided their aggregation during the preparation of the material. Their single-site nature was demonstrated by aberration-corrected transmission electron microscopy and X-ray absorption techniques. They were shown to be active for transfer hydrogenation of nitroarenes into anilines, with excellent substrate selectivity and recyclability, as demonstrated by the preserved yield across seven catalytic cycles. We also showed that FeNx@C could be used to prepare 2-phenylbenzimidazole through a reduction/condensation tandem. Our work shows for the first time the viability of biomass precursors to prepare Fe single-site hydrogenation catalysts.
Titirici M, Baird SG, Sparks TD, et al., 2022, The sustainable materials roadmap, Journal of Physics: Materials, Vol: 5, Pages: 1-98, ISSN: 2515-7639
Over the past 150 years, our ability to produce and transform engineered materials has been responsible for our current high standards of living, especially in developed economies. However, we must carefully think of the effects our addiction to creating and using materials at this fast rate will have on the future generations. The way we currently make and use materials detrimentally affects the planet Earth, creating many severe environmental problems. It affects the next generations by putting in danger the future of the economy, energy, and climate. We are at the point where something must drastically change, and it must change now. We must create more sustainable materials alternatives using natural raw materials and inspiration from nature while making sure not to deplete important resources, i.e. in competition with the food chain supply. We must use less materials, eliminate the use of toxic materials and create a circular materials economy where reuse and recycle are priorities. We must develop sustainable methods for materials recycling and encourage design for disassembly. We must look across the whole materials life cycle from raw resources till end of life and apply thorough life cycle assessments (LCAs) based on reliable and relevant data to quantify sustainability. We need to seriously start thinking of where our future materials will come from and how could we track them, given that we are confronted with resource scarcity and geographical constrains. This is particularly important for the development of new and sustainable energy technologies, key to our transition to net zero. Currently 'critical materials' are central components of sustainable energy systems because they are the best performing. A few examples include the permanent magnets based on rare earth metals (Dy, Nd, Pr) used in wind turbines, Li and Co in Li-ion batteries, Pt and Ir in fuel cells and electrolysers, Si in solar cells just to mention a few. These materials are classified as
Barrio Hermida J, Pedersen A, Feng J, et al., 2022, Metal coordination in C2N-like materials towards dual atom catalysts for oxygen reduction, Journal of Materials Chemistry A, ISSN: 2050-7488
Pedersen A, Barrio J, Li A, et al., 2022, Dual-Metal Atom Electrocatalysts: Theory, Synthesis, Characterization, and Applications, ADVANCED ENERGY MATERIALS, Vol: 12, ISSN: 1614-6832
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- Citations: 56
Geva R, Levy NR, Tzadikov J, et al., 2021, Molten state synthesis of nickel phosphides: mechanism and composition-activity correlation for electrochemical applications, JOURNAL OF MATERIALS CHEMISTRY A, Vol: 9, Pages: 27629-27638, ISSN: 2050-7488
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- Citations: 7
Karjule N, Rana M, Shalom M, et al., 2021, Controlled Nucleation and Growth of Carbon Nitride Films on CNT Fiber Fabric for Photoelectrochemical Applications, Advanced Sustainable Systems, Vol: 5
The controlled growth of carbon nitride (CN) films with tailored electronic properties and surface area is quite challenging due to the solid-state reaction and the lack of efficient interaction between C-N monomers and substrates. Herein, controlled growth of CN films over robust carbon nanotubes (CNT) fiber fabric is reported, which is obtained by either direct calcination of melamine on their surface, that yields a bulk material, or by its chemical vapor deposition resulting in hybrid films. These materials are effective electrodes consisting of high surface-area CN containing CNT fiber fabrics acting as a scaffold and a highly conducting built-in current collector. The results confirm that CNTs act as nucleation centers for the formation of CN films, forming close contact at the CN/CNT interphase, and resulting in efficient charge transfer upon illumination and enhanced electrochemical surface area.
Luo H, Barrio J, Sunny N, et al., 2021, Progress and Perspectives in Photo- and Electrochemical-Oxidation of Biomass for Sustainable Chemicals and Hydrogen Production, ADVANCED ENERGY MATERIALS, Vol: 11, ISSN: 1614-6832
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- Citations: 130
Barrio J, Barzilai S, Karjule N, et al., 2021, Fluorescent Carbon Nitride Macrostructures Derived from Triazine-Based Cocrystals, Advanced Optical Materials, Vol: 9
Carbon nitride (CN) based materials have emerged as efficient photo- and electrocatalysts for various reactions. However, despite their intriguing optical properties (i.e., fluorescence), their utilization as solid-state sensing platforms remains in its infancy, owing to the formation of defect states during the materials synthesis, leading to low emission for the CN powder. Here, a bottom-up synthesis of CN macrostructures with good photoluminescence properties in both liquid and solid state is introduced, from designed triazine-based cocrystals with ordered morphology and tailored chemical composition. Upon calcination at 500 °C, the starting morphology and chemical composition are retained, resulting in the alteration of the HOMO-LUMO distribution of the CN materials, as further supported by density functional theory (DFT) calculations. The good photoluminescence properties of the new CN materials enable their exploitation as environmentally friendly, robust, and cheap sensing material for latent fingerprints labeling and metal-ion detection in water.
Iriawan H, Zamany S, Zhang X, et al., 2021, Methods for nitrogen activation by reduction and oxidation, Nature Reviews Methods Primers, Vol: 1, ISSN: 2662-8449
The industrial Haber-Bosch process to produce ammonia (NH3) from dinitrogen (N2) is crucial for modern society. However, N2 activation is inherently challenging and the Haber-Bosch process has significant drawbacks, as it is highly energy intensive, not sustainable due to substantial CO2 emissions primarily from the generation of H2 and requires large-centralized facilities. New strategies of sustainable N2 activation, such as low-temperature thermochemical catalysis and (photo)electrocatalysis, have been pursued, but progress has been hindered by the lack of rigor and reproducibility in the collection and analysis of results. In this Primer, we provide a holistic step-by-step protocol, applicable to all nitrogen-transformation reactions, focused on verifying genuine N2 activation by accounting for all contamination sources. We compare state-of-the-art results from different catalytic reactions following the protocol’s framework, and discuss necessary reporting metrics and ways to interpret both experimental and density functional theory results. This Primer covers various common pitfalls in the field, best practices to improve reproducibility and cost-efficient methods to carry out rigorous experimentation. The future of nitrogen catalysis will require an increase in rigorous experimentation and standardization to prevent false positives from appearing in the literature, which can enable advancing towards practical technologies for the activation of N2.
Karjule N, Singh C, Barrio J, et al., 2021, Carbon Nitride-Based Photoanode with Enhanced Photostability and Water Oxidation Kinetics, Advanced Functional Materials, Vol: 31, ISSN: 1616-301X
Carbon nitrides (CN) have emerged as promising photoanode materials for water-splitting photoelectrochemical cells (PECs). However, their poor charge separation and transfer properties, together with slow water-oxidation kinetics, have resulted in low PEC activity and instability, which strongly impede their further development. In this work, these limitations are addressed by optimizing the charge separation and transfer process. To this end, a nickel–iron based metal-organic framework, Ni/Fe-MIL-53, is deposited, that acts as an oxygen evolution pre-catalyst within the CN layer and incorporate reduced graphene oxide as an electron acceptor. Upon electrochemical activation, a uniform distribution of highly active oxygen evolution reaction (OER) catalysts is obtained on the porous CN surface. Detailed mechanistic studies reveal excellent hole extraction properties with high OER catalytic activity (83% faradaic efficiency) and long-term stability, up to 35 h. These results indicate that the decrease in performance is mainly due to the slow leaching of the catalyst from the CN layer. The CN photoanode exhibits a reproducible photocurrent density of 472 ± 20 µA cm−2 at 1.23 V versus reversible hydrogen electrode (RHE) in 0.1 m KOH, an exceptionally low onset potential of ≈0.034 V versus RHE, and high external quantum yield.
Li J, Karjule N, Qin J, et al., 2021, Low-Temperature Synthesis of Solution Processable Carbon Nitride Polymers, MOLECULES, Vol: 26
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- Citations: 10
Barrio J, Barzilai S, Karjule N, et al., 2021, Synergistic Doping and Surface Decoration of Carbon Nitride Macrostructures by Single Crystal Design, ACS APPLIED ENERGY MATERIALS, Vol: 4, Pages: 1868-1875, ISSN: 2574-0962
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- Citations: 10
Alonso-Navarro MJ, Barrio J, Royuela S, et al., 2021, Photocatalytic degradation of organic pollutants through conjugated poly(azomethine) networks based on terthiophene-naphthalimide assemblies, RSC ADVANCES, Vol: 11, Pages: 2701-2705
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- Citations: 3
Qin J, Barrio J, Peng G, et al., 2020, Direct growth of uniform carbon nitride layers with extended optical absorption towards efficient water-splitting photoanodes, NATURE COMMUNICATIONS, Vol: 11, ISSN: 2041-1723
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- Citations: 75
Barrio J, Gibaja C, García-Tecedor M, et al., 2020, Electrophoretic deposition of antimonene for photoelectrochemical applications, Applied Materials Today, Vol: 20
Antimonene is a recently developed two-dimensional material with outstanding expected physical properties based on theoretical calculations. Liquid phase-exfoliation has become the most straight forward preparation method to produce stable antimonene suspensions. However, the processing and deposition on substrates of antimonene is still required towards its exploitation in various fields, as current challenges in this research area. Despite the high current research interest in antimonene, the fabrication of Sb-films and its utilization in photoelectrochemical devices remains still unexplored. Herein, the electrophoretic deposition of antimonene on different substrates and its activity as absorber and hole acceptor layer in photoelectrochemical cell (PEC) is reported. The obtained results confirm that the photoelectrochemical performance of the antimonene films electrophoretically deposited on titanium dioxide exhibits an enhanced optical absorption and charge separation properties, compared to pristine TiO2 films. Furthermore, electrochemical measurements reveal that the antimonene films act as hole acceptor layers, enabling better PEC performance.
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