Author: Ana Belen Jorge Sobrido

Welcome to Hattie who joined our group in January 2022 to do a PhD in new freestanding electrocatalysts for CO2 reduction. You can learn more about Hattie here.

Ana has been awarded a Royal Society International Exchanges Grant with MIT.

This grant (March 2022 – March 2024) will start a new collaboration with Prof Brushett from MIT (Massachusetts Institute of Technology, Chemical Engineering Department) and his team. During this collaborative project Prof Brushett and several members of his team will visit our facilities and work in our labs to develop new understanding on electrode materials for redox flow batteries. Likewise, Ana Sobrido and several members of her research group will visit Brushett group’s facilities and acquire new knoweldge in stack testing and techno-economic analysis of the introduction of biomass-waste electrodes and replacement of commercial carbons.

The award will be the foundation for further collaborative research.

Well done to all the members of the team that did a great job presenting their project on 3D printed electrodes, supervised by Wei Tan and Ana Jorge Sobrido! Congratulations

Ana was among the shortlisted candidates for a QMUL Education for Sustainable Development 2022. Although in the end she did not win the award, she had a great time at the amazing Drapers’ Hall, talking to the rest of nominees about their experiences at QMUL.

Efficient Harvesting and Storage of Solar Energy of an All-Vanadium Solar Redox Flow Battery with a MoS2@TiO2 Photoelectrode

J. Mater. Chem. A, 2022 DOI: 10.1039/D2TA00739H

Gengyu Tian, Rhodri Jervis, Joe Briscoe, Madga Titirici and Ana Jorge Sobrido*

Abstract

Solar redox flow batteries constitute an emerging technology that provide a smart alternative for the capture and storage of discontinuous solar energy through the photo-generation of the discharged redox species employed in traditional redox flow batteries. Here, we show that a MoS2-decorated TiO2 (MoS2@TiO2) photoelectrode can successfully harvest light to be stored in a solar redox flow battery using vanadium ions as redox active species in both catholyte and anolyte, and without the use of any bias. MoS2@TiO2 photoelectrode achieved an average photocurrent density of ~0.4 mA cm-2 versus 0.08 mA cm-2 for bare TiO2, when tested for the oxidation of V4+ to V5+, attributed to a more efficient light harvesting and charge separation for the MoS2@TiO2 relative to TiO2. The designed solar redox flow cell exhibited an optimal overall solar-to-chemical conversion efficiency of ~4.78%, which outperforms previously reported solar redox flow batteries. This work demonstrates the potential of MoS2@TiO2 photoelectrode to efficiently convert solar energy in to chemical energy in a solar redox flow battery, and it also validates the great potential of this technology to increase reliability in renewable energies.

Applied Catalysis B: Environmental

Volume 310, 5 August 2022, 121355

Metal tellurides attract recent attention because of their promising applications as effective catalysts for the oxygen evolution reaction (OER). However, inappropriate adsorption energy between OER intermediates and telluride leads to an unsatisfactory electrocatalytic intrinsic activity. Herein, we adopt a unique in-situ cathodic electrochemical activation process to facilitate the surface self-reconstruction to form oxygen vacancy (O_V)-rich TeO₂ layer onto Fe-doped NiTe (O_V@Fe-NiTe). Characterizations and theoretical calculation demonstrate that the presence of the O_V-rich TeO₂ layer realizes the adjustment of d-band center of the active site that translates into an enhancement of the adsorption of *OOH intermediate and thus the optimization of the OER pathway. Consequently, the O_V@Fe-NiTe only requires an ultralow overpotential of 245 mV to drive 100 mA cm^-2 in 1 M KOH, 95 mV lower than that of Fe-NiTe, and hence becoming the best water oxidation electrocatalysts amongst recently reported telluride electrocatalysts. This study presents a unique strategy to exploit telluride-based catalysts through electrochemical surface engineering.

Congratulations to Qian Guo for passing her viva on 25th March 2022 with Prof Steve Dunn and Dr Ludmilla Steier as examiners. Well done Qian! Qian’s PhD project focused on the synthesis and study of photoelectrochemical systems based on hematite for photo-assisted water oxidation, supervised by Dr Ana Jorge Sobrido and Prof Magda Titirici (now at ICL).

Stiven left QMUL and London on the 21st February 2022, back to Medellin, Colombia, to continue his studies in energy storage. Time has gone by really quick, but you managed to get lots of results (including a paper which will be soon published) and engaged with everyone. The group will miss you! Best of luck, and hope we will work again together.

Sustainable Electrodes for the Next Generation of Redox Flow Batteries, by Michael Thielke, Gengyu Tian and Ana B. Jorge Sobrido, J. Phys.: Mater. 2022

Abstract

The development of alternative energy storage technologies is key to advance renewable energy resources. Among them, redox flow batteries have been identified to be one of the most promising technologies in the field of stationary batteries. The carbon-based electrodes in these batteries are a crucial component and play an important part in achieving high efficiency and performance. A further leap into this direction is the design of fossil-free materials by incorporating sustainable alternative resources as the carbon component in the processing of the electrodes. The use of biomass as carbon precursor for electrode applications has also been a focus of research for other energy storage devices and in the case of redox flow batteries, it has become an emergent topic in recent years. This short review presents the recent advances in the design of biomass-derived carbon materials as electrodes in redox flow batteries, strategies to enhance their electrocatalytic properties, challenges, and future outlook in the design of sustainable electrode materials.

Enhancement of the electrocatalytic activity for the oxygen reduction reaction of boron-doped reduced graphene oxide via ultrasonic treatment , published in International Journal of Hydrogen Energy 2022, 47, 5462-5473.

Abstract

Commercial polymer electrolyte membrane fuel cells have relied on scares Platinum to catalyse the kinetically sluggish oxygen reduction reaction occurring at their anodes. Over the last decade organic materials, frequently based on graphitic structures have been demonstrated as promising alternative electrocatalysts to the noble metals. Researchers typically utilize ultrasonic treatment as part of the synthesis procedure to achieve homogeneous dispersion of graphitic carbon prior to. Herein we investigate the implications of the structural and compositional changes induced by the ultrasonication treatment on boron-doped reduced graphene oxide for oxygen reduction reaction. It is shown that ultrasonication pre-treatment prior to the boron doping and reduction of graphene oxide via hydrothermal process step leads to the increase of both substitutional B and electrocatalytic surface area, with associated reduction of average pore size diameter, leading to a significant improvement in the oxygen reduction reaction performance, with respect to the non-ultrasonicated material. It is proposed that the higher degree of substitutional doping of boron is a result of formation of the additional epoxy functionalities on graphitic planes, which act as a doping site for boric acid.