Microwaves for energy-efficient chemical reactions

A means to reduce the energy cost of some industrial processes by using microwaves

University of Tokyo

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Ideally the microwave reactions can be driven by green energy, in which case the system could help reduce carbon dioxide by converting it into other useful chemicals. ©2025 Kishimoto et al. CC-BY-ND

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Credit: ©2025 Kishimoto et al. CC-BY-ND

Some industrial processes used to create useful chemicals require heat, but heating methods are often inefficient, partly because they heat a greater volume of space than they really need to. Researchers including those from the University of Tokyo devised a way to limit heating to the specific areas required in such situations. Their technique uses microwaves, not unlike those used in home microwave ovens, to excite specific elements dispersed in the materials to be heated. Their system proved to be around 4.5 times more efficient than current methods.

While there’s more to climate change than power generation and carbon dioxide (CO2), reducing the need for the former and the output of the latter are critical matters that science and engineering strive to tackle. Under the broad banner of green transformation, Lecturer Fuminao Kishimoto from the Department of Chemical System Engineering at the University of Tokyo and his team explore ways to improve things like industrial processes. Their latest development could impact on some industries involved in chemical synthesis and may have some other positive offshoots. And their underlying idea is relatively straightforward.

“In most cases, chemical reactions occur only at very small, localized regions involving just a few atoms or molecules. This means that even within a large chemical reactor, only limited parts truly require energy input for the reaction,” said Kishimoto. “However, conventional heating methods, such as combustion or hot fluids, disperse thermal energy throughout the entire reactor. We started this research with the idea that microwaves could concentrate energy on a single atomic active site, a little like how a microwave oven heats food.”

As Kishimoto mentions, the process is similar in concept to how a microwave oven works, only in this case, rather than having microwaves tuned to heat polar water molecules at around 2.45 gigahertz (which is also a common Wi-Fi frequency in case you’ve ever noticed that your internet connection becomes unstable when you’re heating leftovers), their microwaves are tuned to much lower frequencies around 900 megahertz. This is because those are ideal to excite the material they wished to heat up, zeolite.

“The most challenging aspect was proving that only a single atomic active site was being heated by the microwaves. To achieve this, we spent four years developing a specialized experimental environment at Japan’s world-class large synchrotron radiation facility, SPring-8,” said Kishimoto. “This involved using spongelike zeolite, which is ideal because we can control the sizes of the sponge cavities, allowing us to balance different factors of the reactions. Inside the sponge cavities, indium ions act like antennas. These are excited by the microwaves which creates heat, which can then be transferred to reaction materials passing through the sponge.”

By selectively delivering heat to specific materials, lower overall temperatures can be used to achieve reactions which are otherwise very demanding, such as water decomposition or methane conversion, both useful to create fuel products. They can further improve selectivity by varying the pore size of the zeolite sponge, with smaller pores yielding greater efficiency and larger pores enabling greater control over reactions.

And one key advantage is that this technique can even be used in carbon capture, recycling CO2 as part of the methane conversion, and even recycle plastics more easily.

The challenge now will be in how to scale this up to encourage industrial adoption — things that work in the lab don’t directly translate into large industrial settings easily. And there are some limitations to the research that would also need to be addressed first. The material requirements are quite complex and aren’t simple or cheap to produce; it’s hard to precisely measure temperatures at the atomic scale, so current data rely on indirect evidence and more direct means would be preferred. And, despite the improvements in efficiency, there is still room for improvement here too as there are heat and electrical losses along the way.

“We aim to expand this concept to other important chemical reactions beyond CO2 conversion and to further optimize catalyst design to improve durability and scalability. The technology is still at the laboratory stage. Scaling up will require further development of catalysts, reactor design and integration with renewable power sources,” said Kishimoto. “While it is difficult to give an exact timeline, we expect pilot-scale demonstrations within the next decade, with broader industrial adoption depending on progress in both technology and energy infrastructure. To achieve this, we are seeking corporate partners to engage in joint development.”

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Journal: Ryo Ishibashi, Fuminao Kishimoto, Tatsushi Yoshioka, Hiroki Yamada, Koki Muraoka, Toshiaki Ina, Hiroki Taniguchi, Akira Nakayama, Toru Wakihara, Kazuhiro Takanabe, “Focused Thermal Energy at Atomic Microwave Antenna Sites for Eco-catalysis”, Science Advances, DOI: 10.1126/sciadv.ady4043, https://doi.org/10.1126/sciadv.ady4043

Funding: F.K. acknowledges that this work was supported by Japan Society for the Promotion of Science (JSPS) KAKENHI Grant-in-Aid for Transformative Research Areas (A) (21H05550 and 23H04097) and Grant-in-Aid for Scientific Research (B) (24K01254). K.M. acknowledges the support of JST PRESTO (JPMJPR2378). T.Y. acknowledges a research fellow (DC1) of Japan Society for the Promotion of Science (JSPS) (22KJ0675).

 

Useful links:

Graduate School of Engineering - https://www.t.u-tokyo.ac.jp/en/

Department of Chemical System Engineering - https://www.chemsys.t.u-tokyo.ac.jp/?lang=en

Caption

This material looks like a rock covered in ice, but under the microscope you would see a spongelike network. This is key to the experiments as the cavities can be filled with specific ions to create heat from microwaves. As the material is porous, fluids can flow through it absorbing the heat to enable reactions. ©2025 Hannes Grobe CC-BY-SA-2.5

Credit

©2025 Hannes Grobe CC-BY-SA-2.5

This material looks like a rock covered in ice, but under the microscope you would see a spongelike network. This is key to the experiments as the cavities can be filled with specific ions to create heat from microwaves. As the material is porous, fluids can flow through it absorbing the heat to enable reactions. ©2025 Hannes Grobe CC-BY-SA-2.5

Credit

©2025 Hannes Grobe CC-BY-SA-2.5

About The University of Tokyo:

The University of Tokyo is Japan's leading university and one of the world's top research universities. The vast research output of some 6,000 researchers is published in the world's top journals across the arts and sciences. Our vibrant student body of around 15,000 undergraduate and 15,000 graduate students includes over 5,000 international students. Find out more at www.u-tokyo.ac.jp/en/ or follow us on X (formerly Twitter) at @UTokyo_News_en.

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Journal

Science Advances

DOI

10.1126/sciadv.ady4043 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Focused Thermal Energy at Atomic Microwave Antenna Sites for Eco-catalysis

Article Publication Date

10-Oct-2025

 

Increasing pressures for conformity de-skilling and demotivating teachers, study warns

University of Exeter

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The increasing pressure for teachers to obey school curriculum policies is “profoundly demotivating” and is leading directly to people leaving the profession, a new study warns.

Teachers value being able to be creative and collaborate with each other to design lessons but are increasingly subject to school policies requiring their conformity.

The research shows this is also reducing their curriculum-making skills and reducing teacher autonomy and motivation, as well as relationships between colleagues and with pupils.

There is a teacher recruitment and retention crisis in England. There is a particular challenge in recruiting physical science teachers, with government targets for recruitment being missed for the last 10 years and a high proportion of physical science teachers leaving early in their careers.

The study says in an era where teacher retention is concerningly low, policies which reduce teacher motivation should be of “profound concern”.

Dr Victoria Wong, from the University of Exeter, who led the study, said: “We have found evidence school and academy trust policies which require conformity are potentially very demotivating for teachers and can deprive them of the opportunity to learn curriculum-making for themselves.

“This might save time in the short term but leads to loss of skills and experience from the profession, both by the direct loss of good teachers from the classroom and by the reduction in opportunities to learn from more experienced colleagues. Neither the loss of experienced teachers nor the loss of skills from the profession will lead to higher quality teaching.”

Dr Wong interviewed 15 very experienced teachers about curriculum-making at academy trust, school or classroom level. The teachers involved had served either 25+ years as a classroom teacher or 20+ years along with having worked with a Learned Society, the Association for Science Education, a relevant educational charity, a government agency or an awarding organisation. Two had spent the majority of their career in grammar (selective) schools, the rest taught mainly in non-selective state schools, several in areas of high socioeconomic deprivation. There were two biology, seven chemistry and six physics teachers.

The interviews showed teachers, especially experienced teachers, are flexible and can and do change their practice. This flexibility is especially apparent when they respond to changes in assessment strategy. Teachers described a variety of creative ways that they had worked to engage and motivate students.

Participants expressed concerns about the lack of confidence of many new teachers to be creative in the classroom and argued that if incoming teachers were unable to become creative, they would be more likely to leave the profession.

Alongside wanting the freedom to teach as they wished, teachers also valued working collaboratively with subject colleagues to improve aspects of their school curriculum and associated resources.

Many teachers reported a reduction in their freedom as individuals and departments to design curricula and teach due to school policies requiring uniformity and conformity in classroom practice. Some of the examples of expected conformity significantly limited teachers’ options in their classrooms.

Several participants argued that teachers are more likely to have the confidence to move away from centrally planned resources with experience and when they are teaching in their own subject area, but science is often taught by non-specialists potentially limiting teachers’ confidence to be creative.

The reasons given for an increase in conformity included: pressure from Ofsted; improving results in external examinations; saving time; improving teaching in the department; wanting to teach in the ‘best’ way and leadership teams not trusting teachers to do a good job if given more independence.

How the ‘best way’ was decided was often unclear. One of the teachers described their senior leadership team looking for examples of practice from schools that were believed to be high performing, with the belief that if those schools taught in a certain way, then that must be the ‘best way’. Other participants raised concerns that decisions about the ‘best way’ were often being made by people who did not have experience of teaching science, arguing that teaching strategies are frequently subject specific and this is not recognised by school policies that prioritise conformity.

Participants described a variety of impacts from the pressure to conform. These included increased monitoring, disciplinary procedures if they did not conform and feeling demotivated.

The opportunity for increased competence and relatedness help to explain why the opportunity to collaborate is an important factor in retaining teachers.

Some participants described curricula planned at the level of the academy trust. These resources may reduce workload but it comes at the cost of opportunities to develop teachers’ confidence, skills and competence in curriculum-making.

Dr Wong said: “Removing the space for teachers to act as professionals and make their own judgements reduces teachers’ autonomy, does not respect or acknowledge their competence and is likely to lead to poorer relationships with students as material is not adapted for them. Three of the participants attributed leaving either a school or the profession to the lack of opportunities that they had for self-determination in the classroom, with several others discussing highly prescriptive institutions that they knew of and asserting that they would not be willing to teach without having autonomy. Trusting relationships between school leaders and staff can support teachers’ motivation and help with retention.”

Reducing teachers’ autonomy deskills the profession. Teachers lacking skill in curriculum design can lead to school leaders choosing to use an externally written curriculum and the problem propagates until the confidence and ability to be creative in the classroom becomes the preserve of the experienced. Several of the participants expressed concerns about the ability of less experienced colleagues to design an engaging curriculum – and that without being able to do so, teaching would be dull and unmotivating, for both teachers and students.

The findings of this study have implications for all subjects and all schools pursuing or considering more restrictive curriculum policies as well as for organisations such as Ofsted.

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Journal

The Curriculum Journal

DOI

10.1002/curj.70007 

Method of Research

Survey

Subject of Research

People

Article Title

Creativity, collaboration and conformity: Curriculum making and teacher motivation

Article Publication Date

9-Oct-2025

 

Researchers develop smarter menstrual product with potential for wearable health monitoring

McMaster University

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These new menstrual cups address usability concerns while opening the door to future health-monitoring capabilities.

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Credit: McMaster University

HAMILTON, ON October 10, 2025 – Researchers at McMaster University have developed a new menstrual health product designed to complement and enhance an existing menstrual cup that is safer, easier to use and more environmentally sustainable than current options.

The innovation is part of a broader initiative at McMaster to develop wearable technologies that proactively monitor women’s health. As part of this work, the research team has published a perspective review in Nature Communications, outlining how emerging technologies, like this new menstrual cup, can be leveraged to detect infections, monitor reproductive health and improve diagnostics.

The new component, described in a paper published in ACS Applied Materials and Interfaces, is a flushable tablet made from highly absorbent seaweed-based material. It’s designed to hold menstrual blood and minimize spills during removal – a common barrier to wider adoption of menstrual cups. This tablet complements the existing Bfree Cup, which is made from lubricant-infused silicone that naturally repels viruses and bacteria and eliminates the need for boiling between uses.

“This project opened my eyes to how urgently innovation is needed in menstrual care,” says Zeinab Hosseinidoust, an associate professor of biomedical and chemical engineering and co-lead researcher on the team. “There’s been little movement in the conversation around menstrual care. Some of that is due to stigma and some is lack of interest, but cups have the potential to make a serious difference in the lives of women around the world.”

The research team also included graduate students Shaghayegh Moghimi and Lubna Najm as well as postdoctoral fellow Fereshteh Bayat, who played key roles in developing and testing.

The product was developed in collaboration with Leisa Hirtz, founder of Women’s Global Health Innovations located at McMaster’s Innovation Park, who approached the researchers.

“Menstrual health is a critical issue for millions of girls and women, particularly those living in poverty in low- and middle-income countries, where access to safe and dignified products remains a barrier to education, employment and social participation. This innovation builds on Bfree Cup’s proven technology to support wider adoption and reduce period poverty. The current research also opens the door to advanced diagnostic capabilities that could transform how we monitor and manage women’s reproductive health globally,” Hirtz says.

Beyond convenience and safety, the technology has the potential to significantly reduce the environmental impact of disposable menstrual products and improve access to menstrual care in lower-income communities. Each cup is designed to last for several years, offering a cost-effective and sustainable solution for users who may not have reliable access to tampons or pads.

Though menstrual cups have long been available, their uptake has been limited due to usability challenges. These new cups address those concerns while opening the door to future health-monitoring capabilities.

The research team envisions future versions of the menstrual products equipped with sensors to detect early signs of infections and blood-borne illnesses – using menstrual blood as a rich source of biological information.

“This could be a new form of wearable technology that could be even more valuable than a smartwatch,” says associate professor of mechanical and bioengineering Tohid Didar, who co-led the research. “We have mainly been reactive in terms of women’s health. This can give us an opportunity to start being proactive. If we can add simple systems to menstrual products to monitor for infections and conditions, such as endometriosis and UTIs, we could find these problems much sooner. There is a lot to explore in this area.”

“Our review underscores how recent advances in biosensors, wearables, and AI can close critical gaps in women’s health diagnostics, from reproductive care to cancer and osteoporosis,” says Wei Gao, professor of Engineering and Applied Science at Caltech and co-author of the Nature Communications perspective.

 

 

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Journal

ACS Applied Materials & Interfaces

DOI

10.1021/acsami.5c16140 

Article Title

Self-Cleaning Menstrual Cups with Plant-Based Biodegradable Superabsorbent Fibrous Tablets for Hygienic and Sustainable Period Car

Article Publication Date

10-Oct-2025