New Publication on the Effect of Reaction Time on Carbon Dot Formation

Carbon dots, a young member of the carbon nanomaterial family, are quasi-spherical nanoparticles, which have fluorescent properties as their key characteristic. A wide range of starting materials and synthetic routes have been reported in the literature, divided into two main categories: a top-down and bottom-up approach. Moreover, a series of different parameters that affect the properties of carbon dots have been investigated, including temperature, starting pH, as well as precursor concentration. However, the effect of reaction time has not been extensively monitored. In our study, a biomass derivative was treated hydrothermally with varying reaction times to draw a solid formation mechanism. In addition, we monitored the effect of reaction time on optical and structural characteristics, as well as the chemical composition of our materials. Our key findings include a four-stage formation mechanism, a higher level of crystallinity, and an increasing brightness over reaction time.

ACS Omega 2019, 4, 26, 21658-21665, Publication Date:December 12, 2019, https://doi.org/10.1021/acsomega.9b01798

New Publication on high volumetric EDLC carbons via hydrothermal carbonization

A novel activation method involving hydrothermal carbonization (HTC) and a pressure-induced low temperature oxidation has been demonstrated for cellulose derived HTC char by using hydrogen peroxide as an active di-oxygen source. The optimized porosity versus gravimetric capacitance results from cellulose derived HTC char synthesized at 220 °C. Almost homogeneous and small particle size micro-ellipse/sphere, relatively high surface area and narrow pore size distributions lead to a high bulk density, i.e. 0.73 g cm−3 , of coating-type electrodes, which is much denser than those manufactured from steam-activated carbons for supercapacitor industry, i.e. 0.52 g cm−3 . The resulting carbon prepared herein achieves a relatively high volumetric capacitance in an organic electrolyte-based supercapacitor, reaching a competitive value of an industrial system with the features being environment-friendly, cost-effective as well as high yield, and less energy consumption.

Qiang Gao and Maria-Magdalena Titirici 2020 J. Phys. Energy 2 025005

New Publication: 3D Carbon Materials for Oxygen and Hydrogen Electrocatalysis

Sustainable energy production at an acceptable cost is key for its widespread application. At present, noble metals and metal oxides are the most widely used for electrocatalysis, but they suffer from low selectivity, poor durability, and scarcity. Because of this, metal‐free carbons have become the subject of great interest as promising alternative electrocatalysts for energy conversion and storage devices, and remarkable progress has been accomplished in the advance of metal‐free carbons as electrocatalysts for renewable energy technologies. Particularly interesting are 3D porous carbon architectures, which exhibit outstanding features for electrocatalysis applications, including broad range of active sites, interconnected porosity, high conductivity, and mechanical stability. This review summarizes the latest advances in 3D porous carbon structures for oxygen and hydrogen electrocatalysis. The structure–performance relationship of these materials is consequently rationalized and perspectives on creating more efficient 3D carbon electrocatalysts are suggested.

Jorge, A. B., Jervis, R., Periasamy, A. P., Qiao, M., Feng, J., Tran, L. N., Titirici, M.‐M., 3D Carbon Materials for Efficient Oxygen and Hydrogen Electrocatalysis. Adv. Energy Mater. 2020, 10, 1902494. https://doi.org/10.1002/aenm.201902494

New Publication: Influence of hydrothermal pretreatment on the pyrolysis of spent grains

Hydrothermal carbonization process (HTC) is a thermochemical process which operates at elevated temperature and pressure, where liquid water is used as a reaction medium [1]. The biomass is converted into a lignite-like solid product called hydrochar [2]. The advantage of hydrothermal treatment is a possibility to convert high moist bio-waste streams without thermal drying. A two-step carbonization process (Figure 5) consisting of HTC and pyrolysis may improve the properties of final biochar (e.g., carbon content, surface area, and electrical conductivity). Hydrothermal conversion occurs using different mechanisms (e.g., hydrolysis and polymerization of intermediates) compared to pyrolysis, due to the liquid water environment, which also improves the heat transfer across the particles [1,3]. Hydrochar can be easily mechanically dewatered, due to higher hydrophobicity than the initial feedstock [2]. The mass of initial biomass is also reduced according to the HTC yield, which results in a lower mass flow of material for pyrolysis reactor and previous drying step. The two-step carbonization concept may spread the range of feedstocks used for biochar production and improve the overall energy efficiency as well as economic feasibility of pyrolysis, using wet biomass streams.

Maciej P. Olszewski, Sabina A. Nicolae, Maria-Magdalena Titirici, Pablo J. Arauzo, and Andrea Kruse, "Influence of hydrothermal pretreatment on the pyrolysis of spent grains" in "Bio-Char II: Production, Characterization and Applications", Franco Berruti, Western University, London, Ontario, Canada David Chiaramonti, RE-CORD, University of Firenze, Italy Ondrej Masek, University of Edinburgh, Edinburgh, United Kingdom Manuel Garcia-Perez, Washington State University, USA Eds, ECI Symposium Series, (2019).

New Publication on Regulating Pore Structure for Enhanced Na Storage Performance

Porous structure design is generally considered to be a reliable strategy to boost ion transport and provide active sites for disordered carbon anodes of Na-ion batteries (NIBs). Herein, a type of waste cork-derived hard carbon material (CC) is reported for efficient Na storage via tuning the pore species.

Benefiting from the natural holey texture of this renewable precursor, CCs deliver a novel hierarchical porous structure. The effective skeletal density test combined with small angle X-ray scattering analysis (SAXS) is used to obtain the closed pore information. Based on a detailed correlation analysis between pore information and the electrochemical performance of CCs, improving pyrolysis temperature to reduce open pores (related to initial capacity loss) and increase closed pores (related to plateau capacity) endows an optimal CC with a high specific capacity of ≈360 mAh g−1 in half-cells and a high energy density of 230 Wh kg−1 in full-cells with a capacity retention of 71% after 2000 cycles at 2C rate. The bioinspired high temperature pore-closing strategy and the new insights about the pore structure–performance relationship provide a rational guide for designing porous carbon anode of NIBs with tailored pore species and high Na storage capacity.

Li, Yuqi & Lu, Yaxiang & Meng, Qingshi & Jensen, Anders & Zhang, QiangQiang & Zhang, Qinghua & Tong, Yuxin & Qi, Yuruo & Gu, Lin & Titirici, Magda & Hu, Yong-Sheng. (2019). Regulating Pore Structure of Hierarchical Porous Waste Cork-Derived Hard Carbon Anode for Enhanced Na Storage Performance. Advanced Energy Materials. 9. 2852

New Publication on Lignin-Derived Electrodes for Redox Flow Batteries

Redox flow batteries represent a remarkable alternative for grid-scale energy storage. They commonly employ carbon felts or carbon papers, which suffer from low activity towards the redox reactions involved, leading to poor performance. Here we propose the use of electrospun freestanding carbon materials derived from lignin as alternative sustainable electrodes for all-vanadium flow batteries. The lignin-derived carbon electrospun mats exhibited a higher activity towards the VO2+/VO2+ reaction than commercial carbon papers when tested in a three-electrode electrochemical cell (or half-cell), which we attribute to the higher surface area and higher amount of oxygen functional groups at the surface. The electrospun carbon electrodes also showed performance comparable to commercial carbon papers, when tested in a full cell configuration. The modification of the surface chemistry with the addition of phosphorous produced different effect in both samples, which needs further investigation. This work demonstrates for the first time the application of sustainably produced electrospun lignin-derived carbon electrodes in a redox flow cell, with comparable performance to commercial materials and establishes the great potential of biomass-derived carbons in energy devices.

Maria Crespo Ribadeneyra, Lia Grogan, Heather Au et al., 2019, Lignin-derived electrospun freestanding carbons as alternative electrodes for redox flow batteries, Carbon, ISSN 0008-6223

Hande Alptekin gave a talk as a Student Programme Leader at Imperial College`s PGR Welcome Event

Hande gave a talk as Research Impact & Societal Engagement Student Programme Leader and introduce her particular programme at the Postgraduate Research Student Welcome Event

New Publication On Porous Carbon Nanosheets For ORR

Pyridinic-N configurations and intrinsic defects on nanocarbons have been regarded as potentially active-sites for the oxygen reduction reaction (ORR). In this work, a facile strategy is demonstrated to achieve pyridinic-N dominated porous carbon nanosheets with edge-enriched defective nature through the selection of the bio-precursor guanine as C/N sources. It is able to achieve high contents of pyridinic-N dominated (48.1% from gross N) species and the few-layers carbon architectures with hierarchical porosity by a template-free carbonization method. These 2D carbon structures are of low cost, scalable and economically attractive while based on renewable and highly abundant resources. As a result, the optimized catalyst delivers a significantly enhanced electrocatalytic performance for ORR under wide range of pH from alkaline to acid, i. e. possessing a 30 mV more positive half-wave potential (0.885 V) than Pt/C (0.855 V) catalyst in 0.1 M KOH, and very close activities to Pt/C in 0.1 M PBS and 0.1 M HClO4 solution. This ORR performance is attributed to the synergistic effects of unique graphene-like architecture, high porosity, and coexistences of high contents of pyridinic-N species and abundant edge/defect sites.

Huang B, Liu Y, Guo Q, Fang Y, Titirici MM, Wang X, Xie Zet al., 2020, Porous carbon nanosheets from biological nucleobase precursor as efficient pH-independent oxygen reduction electrocatalyst, Carbon, Vol: 156, Pages: 179-186, ISSN: 0008-6223

Magda Titirici will be the academic lead for Imperial College London in a project funded by The Faraday Institution

The Faraday Institution has announced five new projects with £55 million of funding to help improve batteries used for transport and energy storage.

Imperial College London is part of a new project funded by the Faraday Institution to enable rapid improvements in Lithium Sulfur batteries by generating new knowledge, materials and engineering solutions.

Magda Titirici has been named RAEng Chair of Sustainable Energy Materials for Emerging Technologies

Intelligent and resilient ocean engineering, new kinds of batteries and more precise x-ray scans are among the disruptive innovations being developed by the Royal Academy of Engineering’s latest Chairs in Emerging Technologies announced.

Professor Magda Titirici has been named Chair of Sustainable Energy Materials for Emerging Technologies. She will receive over £2.7 million in funding over ten years.

Hui Luo Poster Prize at LEMD2019

Hui Luo has won the Best Poster Prize at 2nd London Energy Material Division Symposium hosted at University College London.

Solar Fuels Poster Prize

Hui Luo has been awarded the Best Poster Prize at 7th UK Solar fuel Network hosted in the University of Cambridge.

Hui Luo wins Poster Prize in Porto, 2018

Hui Luo has been awarded a Materials Horizons Poster Prize at the 8th International Symposium on Carbon for Catalysis CarboCat VIII at Porto, Portugal.

Alain Li joins group as Post-Doctoral Researcher

Alain Li joined the group as a postdoc in June 2019, after obtaining his PhD from McGill university in Montréal (Québec). He has high hopes on London being less cold. In the Titirici group, will work on Fe/N-doped carbon catalysed hydrogenation of biomass compounds.

Sabina Nicolae wins Poster Prize at HTC Conference

Sabina A. Nicolae, received a 1st place poster prize for the work on “Biomass based carbon materials for gas storage and separation” , during the 2nd International Symposium on Hydrothermal Carbonisation, organised by German Biomass Research Center DBFZ.

The 2nd International Symposium on Hydrothermal Carbonisation, took place on 14-16th of May,2019, in Berlin Germany, and it was focused on recent developments, driven by both fundamental research and applied technology. Researchers from diverse disciplines ranging from chemists, material and chemical engineers, to agricultural and soil scientists were invited. Companies in solid waste, wastewater treatment, as well as those in the agricultural and energy industries with feasibility studies or full-scale technological applications were also invited. The symposium offered a platform for discussions across disciplines and between researchers and practitioners.

Sabina Nicolae wins 1st Place Poster Prize at Barrer Symposium

Sabina A. Nicolae, was presenting her work on CO2 adsorbents at the Barrer Symposium on Separation Materials organised by Barrer Centre and Imperial College London, on 14th of November 2018.  The poster has been awarded with the 1st place in the poster competition.

Barrer Symposium on Separation Materials brings researchers from academia and industry as well as users of modern separation techniques, providing a forum for discussion on challenges and benefits, exchange of ideas and experiences, and exploration of possible collaborations.

IOM Young Person's Lecture Competition London Heat Winner - Sabina Nicolae

Sabina A. Nicolae, a SEMS PhD student supervised by Magda Titirici and Ana Jorge Sobrido, has won the London heat of the IOM Young Person’s Lecture Competition (YPLC) 2018. The YPLC invites students and professionals up to the age of 28 to deliver a short lecture on a materials, minerals, mining, packaging, clay technology and wood science related subject. Candidates compete in a series of heats organised by local affiliated societies of the Institute, from which six regional candidates are selected to compete in the national final.

The event was held on 1st of February 2018, at London Materials Society, Sabina was selected from among 5 competitors from other London-based universities.