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Department of Chemical Engineering and Biotechnology


Our work featured by The Chemical Engineer!

Chemical looping on the cover of the April issue of The Chemical Engineer! Moreover, Joe's work on producing acetaldehyde from ethanol using chemical looping is in the article's highlight. Amazing cover for this issue!



Kenny and Alex describe energy research during School Visits

Our Department is quite popular! We hosted a few school visits, some in connection to the ongoing Cambridge Festival. Kenny and Alex discussed how our work could help produce key chemicals in an environmentally-sound way, using only renewable resources. Hopefully, we'll see some of our guests in the next CEBT cohort!



George visited CARES and NTU

George has just returned from a month-long research visit to the Cambridge Centre for Advanced Research and Education in Singapore (CARES) for some collaborative work with Asst. Prof. Paul Liu (also NTU) and Xianyue Wu.  During his stay in the CARES laboratory, George was able to characterise the adsorption interactions of hydrogen and carbon dioxide with copper-based catalysts used for methanol synthesis. A chemisorption analyser allowed the adsorption sites and their capacities to be probed, and in-situ infrared spectroscopy was then used to investigate the nature of reactive intermediates formed on the catalysts after adsorption of hydrogen and carbon dioxide. George wishes to thank Cambridge CARES for their financial support in enabling the trip, and for their warm hospitality during his visit. We look forward to publishing the results from George’s trip.



Joe et al. demonstrate that acetaldehyde can be produced using the chemical looping approach

Exciting news - Joe, Kenny, Abu and George published a paper where they demonstrate for the first time the production of acetaldehyde using oxygen from a solid material, SrFeO3, with the process following the chemical looping approach. The big benefit of conducting the selective oxidation step, in which ethanol reacts with lattice oxygen, producing acetaldehyde and water, is the improved safety and intensification of the process. The team show results that reach >90% selectivity to acetaldehyde and >60% conversion of ethanol, matching the performance of the incumbent Veba-Chemie process, but at a temperature 250degC lower! Well done!



Kenny publishes a new paper in Fuel

Dr Kwong reached another milestone - he published his fifth first-author paper originating from his PhD. This time he looked into analytical modelling on combusting biochar in Chemical Looping with Oxygen Uncoupling (CLOU) setups. Kenny shows that a range of simplification leads to acceptable solutions, and discusses the limits of applicability. Well done, Dr Kwong.


Paula wins the Best Presentation Award

Congratulations to Paula Mendoza-Moreno, current PhD candidate in the Energy Reactions and Carriers group, who received the Best Presentation award in the Whole system approach & Policy session at the 7th World Energy Storage Conference. Paula was recognised for her work on the impact of controlled ortho- to para-hydrogen conversion on liquid hydrogen production for energy storage. The investigation focused on the performance of a hydrogen liquefaction plant involving a detailed study on the transition between hydrogen nuclear isomers from the first and second laws of thermodynamics, and environmental sustainability perspectives. We look forward to reading Paula’s upcoming paper on the topic soon.


Energy Reactions and Carriers Group at the 2022 Maxwell Centre Annual Research Showcase

Last week, two Ph.D. students from our group presented their work at the Maxwell Centre Annual Research Showcase, highlighting two projects within the group on chemical looping approaches to sustainable chemical production. Joe Gebers presented work on point-of-use production of ethylene oxide, regarding the design of a chemical looping system for converting ethanol to ethylene oxide, a medical sterilising agent in short supply in low-income areas. Joe is continuing these studies into sustainable, low-cost ethylene oxide production for his Ph.D. project. Abu Kasim presented his work on the H2Upgrade project, for producing sustainable hydrogen. In his work, iron-based materials were designed to utilise the reducing potential from waste industrial solvent streams (such as acetone or butanol) to reduce an oxygen carrier, and then thermo-chemically split water to generate hydrogen and close the chemical loop.

We would like to thank the Maxwell Centre for the use of their equipment in producing the work for this project, and for hosting the research showcase, and to UKRI and BEIS for funding Joe and Abu’s work on these projects.




Chemical Looping Conference in Zaragozza, Spain

A fortnight ago, Alex and Ewa attended the 6th International Conference on Chemical Looping in Zaragoza, Spain. Hosted by the Instituto de Carboquímica (ICB-CSIC), this conference featured talks on all aspects of chemical looping, from operation of pilot-scale chemical looping combustion reactors for efficient carbon capture, improvements to synthetic oxygen carriers, and entirely novel catalytic processes using chemical looping principles. Alex and Ewa presented our groups’ work on improved materials for chemical looping air separation, and a novel process for production of acetaldehyde via chemical looping respectively, which they are currently working to publish in the near future. We thank the ICB-CSIC for hosting such an enjoyable conference, with interesting talks and great opportunities to meet friends and collaborators.



Alex's article is out!

Now in a fully published version, Alex's article in RSC Reaction Chemistry and Engineering is out. This is a peer-reviewed version of his work on "Selective formation of propan-1-ol from propylene via a chemical looping approach". Good read and highly recommended to anyone interested in reaction mechanisms and chemical looping methods applied to selective production of high-value chemicals. We are looking forward to Alex's next piece of work. Stay tuned for news from Zaragoza!



Alex presents his work at the ACS Fall Conference in Chicago

Alex Harrison is now on a tour in the US; the main stop: the American Chemical Society Fall Conference in Chicago. Alex presented in the Aerobic Oxidation symposium, organised by the ACS Division of Catalysis Science and Technology. Alex presented his recent work (incoming publication!) titles "Selective formation of propan-1-ol from propylene via a chemical looping approach". And here he is:




New paper by Kenny, Walid and Luke!

When a solid carbon reacts with O2, a mixture of two product species is obtained: CO and CO2. When combusting various solid carbonaceous fuels, such as biochars, the distribution of the products changes, which means the time of combustion should change. Sounds intuitive and fundamental but, in fact, is not simple to investigate experimentally because CO can react further, using up O2. Glad to present our approach with the study led by Kenny Kwong, who also mentored Walid Moujar and Luke Mleczko. Walid and Luke worked with us in their final research project, and now, we can show you the results:




Visit of Prof. Fanxing Li (North Carolina State University, US)

Prof. Fanxing Li visited us on his way to Berlin, where he starts his Humboldt Fellowship. Thank you, Fanxing for the presentation on your recent research! Here, is a photo of us visiting Gonville and Caius College:



Aya and George presented their research at the 2nd International Conference on Negative CO2 Emissions (Gothenburg, SE)

Aya Ennaciri (MPhil in Biotech) and Goerge Fulham (1st year PhD) from ERC travelled to Sweden to present the results of the last 8 months of their work in our group:

Aya Ennaciri, Alexandra Clarà Saracho and Ewa J. Marek; Bacteria-induced mineralisation for enhanced removal of CO2

George J. Fulham and Ewa J. Marek; The Use of Zirconia and Ceria in Copper-Based Catalysts for Power-to-Methanol Synthesis at Atmospheric Pressure

Aya's work titled Both had oral presentations, and secured funding, Aya from the CEB Conference Fund, and George from RSC Travel Fund. Congratulations!



Joe and Alex published their first paper

The paper focuses on the chemical looping epoxidation of ethylene, where the main product: ethylene oxide is produced in one step of the process, and in the subsequent step, our active material (Ag/SrFeO3) is regenerated. Joe looked at decreasing the time for regeneration while increasing the time for producing the epoxide. The paper shows that we can still reach almost 20% conversion of ethylene and over 60% selectivity for the epoxide product when the regeneration is shortened to 5 min, but run at 2.5 bar. Great results!



Can we combust industrial glycerol in a fluidised bed?

Tom McCann (MPhil project with our group in 2019) and members from the ERC group published a paper describing Tom's results. Namely, we demonstrated the combustion of industrial waste glycerol in a fluidized bed for over 4 h. Moreover, the combustion was autothermal and self-sustained. We've been waiting for this paper for quite a while but it was surely worth it. Well done, Tom!



Joe presented at the UK Chem Eng Days in London

Our delegation comprising Joe, Paula and Ewa attended ChemEngDays UK 2022 at University College London. Additionally, Joe presented his work on chemical looping epoxidation both as a flash presentation and a poster. Well done, Joe!



Kenny presented at the Low-Carbon Combustion conference

Kenny presented his work on biomass combustion in various chemical looping materials at the 2nd Low-Carbon Combustion Conference. The conference was organised in Cambridge by the British and French sections of the Combustion Institute. This is the second time Kenny is presenting at the Low-Carbon conference; last year he presented remotely for the conference in Lille.

The work was co-authored by Alex and Joe. The full title: "The utilisation of Fe2O3, CuO and SrFeO3 oxygen carriers in chemical looping combustion of biomass"

Well done Kenny, Alex and Joe!


Dr Bond, Zach Bond!

Zach defended his thesis in flying colours. Well done and well-deserved, Dr Bond.


Abu published his MPhil results in Journal of Power Sources!

We have some exciting results to share. With Abu Farhan Bin Abu Kasim (MPhil ACE), we investigated whether one could retrofit a Cessna aircraft to be powered by liquid hydrogen used in a Fuel Cells Power System (FCPS). The work has been just published, describing the failure analysis and possible configuration of an optimal FCPS. Kudos to Abu Farhan Bin Abu Kasim! This was his MPhil research project in collaboration with Stratospheric Platforms Ltd. Well done, Abu!


Allan's review paper in Progress and Energy and Combustion Science is out

Allan's huge work, created as a hobby during the last lockdowns has been now published. This is a large and full of intricate details paper explaining the state of the art of mass spectrometric methods applied in researching flames. Congratulations, Allan!






Kenny and Ewa published a review paper in Energy&Fuels

Exciting news; Kenny and Ewa's review paper has been finally published. They wrote about the combustion of biomass in fluidised beds, with a review focusing on recent developments in the field. The paper is a perfect starting point for young researchers working on the efficient usage of biomass in energy technologies. Good job Kenny. Publishing two papers in one year is quite an achievement!



Kenny presents his recent research at the FERIA Conference in Nottingham

Kenny Kwong (now a fourth-year Ph.D. student) represented our group at the 1st FERIA conference. FERIA stands for Fuel and Energy Research and Its Applications. Kenny's presentation described biomass char combustion and predictions for burnout times, based on pre-determined CO/CO2 ratios. Sounds complex? Kenny derived an analytical solution that can predict burnout times quite easily! Congrats Kenny, well done! (and we're looking forward to your paper from the conference in the special issue of Fuel).



Enrique's M.Phil. results published in Chemical Engineering Journal

Enrique did his MPhil research project on chemical looping epoxidation of ethylene. He investigated how the presentation of the catalyst affects the selectivity of epoxidation towards ethylene oxide. The results show that the contact between the catalyst (Ag) and supporting material (SrFeO3), which also works as an oxygen donor to the reaction, needs to be firm. This can be achieved, for example, by high-temperature calcination of the Ag-SrFeO3 composite. After the treatment, the Ag particles are larger and more reactive. In the end, Enrique was able to achieve selectivity to ethylene oxide of 60% at ethylene conversion >15%, and both stable over 10 chemical looping cycles. This is so far our record! Great job, Enrique.

Marek EJ, García-Calvo Conde E. Effect of catalyst preparation and storage on chemical looping epoxidation of ethylene.



Andras, Thomas and Zach published a paper on fast-speed analysis of biomass-derived pyrolitic gases using a flame ionisation detector

Andras and Thomas (our IIB students from 2019), supported by Zach, published a fantastic paper on using a well-known technique - flame ionisation to detect pyrolytic gases, for the first time in-situ, so at the time of the pyrolysis experiments. The paper describes their adventure into the study and the obtained results. The novel method allows analysing the total amount of carbon in the evolved raw, pyrolytic gases without the need for gas cleaning and tar removal, hence, offering insight into pyrolysis that was not available before. Well done!

Volford A, Redko T, Bond Z, Marek EJ, Hayhurst AN. Using a flame ionisation detector to measure the rate and duration of pyrolysis of a biomass particle. Combustion and Flame,




Samuel published his first paper on tailoring oxygen carriers for chemical looping epoxidation (CLE)

Samuel's recent work demonstrates the synergy between two strontium ferrite perovskites: SrFeO3 and Sr3Fe2O7 when used as oxygen carriers for chemical looping epoxidation. Separately, each of the perovskites is worst than a fair mix of both materials, and this applies to all properties: rate of oxygen release and uptake, stability in cycling, selectivity towards the epoxide (here: ethylene oxide). Samuel's work proves that we can tailor the performance of oxygen carriers, matching their chemical potential with reaction requirements. We are looking forward to the next step, Samuel!


Gabra S., Marek E.J., Poulston S., Williams G., Dennis J.S. The use of strontium ferrite perovskite as an oxygen carrier in the chemical looping epoxidation of ethylene. Applied Catalysis B: Environmental.


Kenny published his first paper on chemical looping combustion (CLOU)

Kenny's first paper on CLOU with biomass char and CuO particles is out (link below). This is an important piece of work developing the first analytical solution to char conversion in a CLOU setup. The model allows predicting the burnout time in any CLOU setup easily, for any stoichiometric oxides (CLOU particles). We are looking forward to the next part of this research. Stay tuned!

Kwong K., Mao R, Scott S.A., Dennis J.S., Marek E.J., 2020. Analysis of the rate of combustion of biomass char in a fluidised bed of CLOU Particles. Chemical Engineering Journal,


New paper co-authored by E.J. Marek. Does the reaction product influence the process in gasification? Yes, and it's quite a change.

Most studies use Ergun's rate of reaction to describe gasification of a solid char by CO2 into a gases fuel, carbon monoxide. Ergun's expression seems to have it all... and, indeed, that's why it is so successfully used (e.g., Marek EJ et al. 2018). In this study, led by Dr Yaoyao Zheng, we show that Ergun did not include the inhibiting effect of CO, and this omission influences the rate significantly! We propose a new expression for the rate that captures also the influence of CO. Have a look at the paper below. It will be presented in January at the International Symposium on Combustion. Great work Yaoyao and good luck at the conference!

Zheng Y, Marek E.J., Scott S.A. 2020 The effect of CO on CO2-char gasification. Proc Combust Inst.

New paper co-authored by E.J. Marek is out. Can we model chemical-looping with a discretised porous particle? Yes, we can.

Some materials are porous, others are not. Obviously this influences their reactivity in heterogeneous reactions. To observe the progress of a reaction, we modelled hematite particles under reduction with CO/CO2 mixture. Results show how different two materials with identical chemical composition can be. Here we had one type of hematite derived from ore, the other synthesised in the lab.

Jovanovic R., Marek E.J., 2020 Percolation theory applied in modelling of Fe2O3 reduction during chemical looping combustion. Chem. Eng. J.




New paper co-authored by E.J. Marek is out. This time the story involves microbes.



Some bacteria are amazingly effective in producing CaCO3. This biomineralised carbonate can have a bountiful range of applications in construction engineering. The paper characterises how efficiently various bacteria strains precipitate CaCO3. The image shows three mineral presentations of precipitated CaCO3 - all created by microbes.

Saracho, A.C., Haigh, S.K., Hata, T., Soga, K., Farsang, S., Redfern, S.A.T., Marek, E., 2020. Characterisation of CaCO3 phases during strain-specific ureolytic precipitation. Sci. Rep. 10, 1–12.


IIBs projects finished.

Jo, Alex, Udayin, Shekeil, Walid, and Luke finished their IIB projects and submitted their research reports. Congrats!


IIBs presenting their research projects.

Jo, Alex, Udayin, Shekeil, Walid, and Luke presented their research projects today. They gave a 6-min teaser presentation at the Department, followed by a poster session. Noone has any doubts these are our new experts on the combustion of waste fuels, CO/CO2 ratios from burning chars, promoters in CL epoxidation. Well done!

If you have problems with incomplete combustion (e.g., CO in the off-gas), go and talk to Jo and Alex.

Luke and Walid can tell you how to determine the CO/CO2 ratio from combustion of char, and then model for the burnout time.

If you have a catalytic reaction, go to Shekeil and Udayin to discuss promoters.


Boom is joining the Combustion Group.

Jiratheep Pruchyathamkorn - Boom is joining our group for his 8-week Mini research project. Boom is a NanoDTC student and he will be using his nano-skills to look at materials for CL-epoxidation. He will investigate how do the CL-catalysts work and which phases are active in reactions.


We are saying good-bye to Prof. John Davidson.

Prof. John Davidson passed away. He was the brightest and kindest supervisor, mentor and colleague. Without him, the group will not be the same. We will continue his fundamental work on fluidisation, hoping that would make him proud. He will be deeply missed.


Investigating redox kinetics of SrFeO3-δ. Another paper out in the world.

This is a second paper from Richard Goerke's Ph.D. thesis. Here, we determined kinetic parameters for SrFeO3-based perovskites. It is the first study, in which the dependence between pO2, non-stoichiometry of perovskite (δ), and the temperature is experimentally investigated. The paper is linked here.


Andras and Thomas' paper in Combustion and Flame is out!

These guys did a great job during their IIB project with us. Both are now working as chemical engineers! Congrats about the paper and about your new careers!

Free access link is here. In this paper, we describe how to determine important parameters for biomass and char (obtained after pyrolysis of biomass). Only by getting the parameters, such as thermal conductivity, right, can we model the energy conversion of biomass correctly.


Samuel around the globe: now in Beijing, China

Samuel Gabra has been invited to a Graduate Conference at the Tshigua University in China. Samuel received a full scholarship for this, being selected as the only Ph.D. student from Cambridge. We have no pictures of him in China just yet, so the readers just need to believe this news.


Samuel at a conference in the US

Samuel Gabra is presenting his research at the AIChE Conference in Orlando, US. This year the theme is "Transforming the Future through Chemical Engineering".

On Wednesday, Nov 13, Samuel will be presenting a paper titled: "MoVNbTeO for Chemical Looping - Oxidative Dehydrogenation of Ethan", co-authored with Dr S.A. Scott, G. Williams, S. Poulston, Prof. J.S. Dennis. The session will be in a Regency Ballroom!





The Combustion group gets bigger

Welcome two new Ph.D. students, Thomas and Ben!

In October, Thomas Z. Sun and Ben Houlton have joined our group. Both will be working on chemical looping. Good luck with your Ph.D. and welcome!