Green Chemistry Blog

Green Chemistry is proud to present the Green Chemistry Emerging Investigators Series, showcasing work being conducted by Emerging Investigators. This collection aims to highlight the excellent research being carried out by researchers in the early stages of their independent career from across the breadth of green chemistry.  For more information about this series, click here

Among the contributions to this series is a Tutorial Review entitled Covalent organic frameworks as heterogeneous photocatalysts for cross-coupling reactions (DOI: 10.1039/D4GC03467H).

Read our interview with the corresponding author, Dr Pradip Pachfule.

Could you briefly explain the focus of your article to the non-specialist? This article explores the potential of covalent organic frameworks (COFs) as solid, reusable photocatalysts that facilitate significant bond-forming reactions in organic chemistry using visible light. COFs offer a greener alternative to conventional metal-based homogeneous catalysts by combining structural order, porosity, and light-harvesting ability. The review highlights how these materials enable sustainable cross-coupling reactions, which are relevant to the production of pharmaceuticals and fine chemicals.

How would you set this article in a wider context?

 Cross-coupling reactions are indispensable in modern synthesis, but they often rely on catalysts that are expensive, toxic, and difficult to recycle. In the broader context of green and sustainable chemistry, there is a strong push toward heterogeneous, light-driven catalytic systems that reduce waste and energy input. This article examines the intersection of COFs with materials chemistry, photocatalysis, and organic synthesis; highlighting their growing significance as a bridge between fundamental design and practical sustainability.

What is the motivation behind this work?

 The motivation stems from the need to replace conventional homogeneous photocatalysts with robust, recyclable, metal-efficient systems that perform just as well. COFs provide a distinctive platform that enables the translation of molecular-level design into solid-state photocatalysts with tunable optoelectronic properties. Our goal was to evaluate how these features could be used to make cross-coupling chemistry more sustainable and scalable.

What aspects of this work are you most excited about at the moment and what do you find most challenging about it?

 We are particularly excited by our ability to design COF backbones with precise control over light absorption, charge separation, and proximity of catalytic sites, features that are difficult to achieve simultaneously in other materials. However, the most challenging aspect remains establishing clear structure–activity relationships and unambiguously identifying active catalytic pathways in complex, heterogeneous photocatalytic systems.

What is the next step? What work is planned?

 The next step is to transition from proof-of-concept reactions to more general, scalable, and mechanistically well-understood COF-based photocatalytic systems. Our focus is on developing fully metal-free or earth-abundant metal COFs, improving quantum efficiencies, and expanding to more synthetically demanding transformations such as C-H and C-F activation. Integrating operando spectroscopic techniques to probe charge-transfer pathways is also a key priority.

Please describe your journey to becoming an independent researcher

My journey has been shaped by interdisciplinary training in porous materials, catalysis, and energy-related chemistry, as well as strong mentorship during my doctoral and postdoctoral research in India, Japan, and Germany. These experiences have helped me to appreciate the importance of a fundamental understanding that is also applicable to the real world. My independent research program allows me to explore long-term questions in COF chemistry with a strong emphasis on sustainability.

Can you share one piece of career-related advice or wisdom with other early career scientists?

Choose research problems that genuinely excite you and that have long-term relevance, even if progress feels slow at times. Building depth and originality matters more than following trends. At the same time, collaborating with others and being open to learning across disciplines can significantly accelerate scientific and personal growth.

Why did you choose to publish in Green Chemistry?

Green Chemistry is a leading journal that emphasizes sustainability, innovation, and real impact. It values that align closely with our work on photocatalysis and recyclable materials. With its broad, interdisciplinary reach, the journal is an ideal platform to demonstrate the importance of COF-based photocatalysts to chemists and materials scientists alike.

Meet the author

Dr Pradip Pachfule studied chemistry at Solapur University, India, and graduated in 2008. He received his Ph.D. from the CSIR-National Chemical Laboratory, Pune, India, under the supervision of Prof. Rahul Banerjee in 2014. Later, he worked as a JSPS postdoctoral research fellow in the laboratory of Prof. Qiang Xu at AIST, Kansai, Japan. This was followed by working in the group of Prof. Arne Thomas as an Alexander von Humboldt postdoctoral fellow and a postdoctoral research fellow at the Technische Universität Berlin, Germany (2017–2021). He is currently working as an associate professor at S. N. Bose National Centre for Basic Sciences, Kolkata, India. His research is focused on covalent organic frameworks and their applications in photocatalytic organic transformation, water splitting, and energy storage.

Green Chemistry is proud to present the Green Chemistry Emerging Investigators Series, showcasing work being conducted by Emerging Investigators. This collection aims to highlight the excellent research being carried out by researchers in the early stages of their independent career from across the breadth of green chemistry.  For more information about this series, click here

Among the contributions to this series is a Tutorial Review entitled Fundamental, technical and environmental overviews of plastic chemical recycling (DOI: 10.1039/D4GC03127J).

Read our interview with the corresponding author Dr Hui Luo below.

Could you briefly explain the focus of your article to the non-specialist?  Our article provides a clear and critical overview of how different chemical recycling technologies can be used to tackle plastic waste that cannot be effectively recycled mechanically. We compare how various plastics respond to different chemical processes and assess not only their technical feasibility, but also their environmental and economic impacts. The goal is to clarify where chemical recycling truly adds value in a circular plastics economy.

How would you set this article in a wider context?

Plastic pollution, resource depletion and climate change are tightly connected challenges. While mechanical recycling remains essential, it cannot deal with all plastic waste streams or maintain material quality indefinitely. Chemical recycling is increasingly seen as a complementary solution, and our article helps position these technologies realistically within broader waste management systems, industrial infrastructure and net-zero ambitions.

What is the motivation behind this work?

As a material scientist and chemical engineer, I got into the research of plastic chemical recycling about 3-4 years ago when developing my own independent research. There was a lot to learn and I noticed different technologies often discussed in isolation or without sufficient sustainability assessment. Through talking with the other co-authors working on different aspects of plastic recycling, we were motivated to bring together fundamental chemistry, process engineering and life-cycle perspectives to provide a balanced, evidence-based guide. Ultimately, the aim was to help researchers, policymakers and industry identify which technologies make sense for which plastics, and under what conditions.

What aspects of this work are you most excited about at the moment, and what do you find most challenging about it?

I’m particularly excited by emerging technologies or processes that can handle mixed or contaminated waste streams more effectively. The biggest challenge chemical recycling faces in regards to mechanical recycling, is how to reduce energy consumption, especially at scale, to allow the process to be profitable and attractive. I think a lot of efforts are putting into addressing this challenge in both academia and industry as we speak.

What is the next step? What work is planned?

The next step is to take all the learnings on board to develop recycling processes that are lower-energy, more contaminant-tolerable, and validating them at larger scales. In my group, we develop a mechanocatalytic process, which utilises mechanical forces and catalysts to depolymerise different plastics into monomers or other value-added chemicals. We aim to develop it into a technology that operates with low temperature at ambient temperature, to minimise energy consumption and maximise the product yields.

Please describe your journey to becoming an independent researcher

I obtained my PhD in 2019 from Queen Mary University of London, working on waste-derived carbon materials for solar hydrogen conversion in Prof. Magda Titirici’s group. I then followed an academic path to work as a postdoctoral research associate at Imperial College London, where I initiated and led the sub-group on electrochemical biomass conversion. In 2022, I decided to see how research can make real-life impact by taking the senior test engineer role in Ceres Power and learned from this short industrial experience about technology translation and scaling-up. Inspired by how innovative technology can reshape industrial sectors, In 2023, I returned academia and started at University of Surrey as a Future Fellow to work on my original and independent research of combining mechanocatalysis and electrocatalysis for plastic recycling, and later been awarded the Royal Academy of Engineering Research Fellow in 2024.

Can you share one piece of career-related advice or wisdom with other early-career scientists?

Try to build both depth and perspective: develop strong technical expertise, but also understand how your work fits into bigger societal and industrial contexts. Also, personal development is equally important to research development, make sure to build your own research vision and the necessary technical/soft skill sets to transit into independence.

Why did you choose to publish in Green Chemistry?

Green Chemistry is always a place to look for sustainable and novel chemical processes ever since I was doing my PhD. Over the years I have also published and peer-reviewed for Green Chemistry, so I am certain the journal’s emphasis on environmental performance, systems thinking and responsible innovation aligns perfectly with the goals of this review and with the broader direction of our research

Meet the author

Dr Hui Luo received her Ph.D. in Materials Science from the Queen Mary University of London in 2019, before moving to Imperial College London as a Research Associate. She then worked in the green hydrogen industry for a year before taking an independent Surrey Future Fellowship at the University of Surrey in 2023. Her research focuses on developing and up-scaling efficient chemical recycling and electrolysis technologies to convert biomass and plastic wastes into green hydrogen and high-value commodity chemicals, with low energy consumption and minimal carbon footprints.

Green Chemistry is proud to present the Green Chemistry Emerging Investigators Series, showcasing work being conducted by Emerging Investigators. This collection aims to highlight the excellent research being carried out by researchers in the early stages of their independent career from across the breadth of green chemistry.  For more information about this series, click here

Among the contributions to this series is a Paper entitled Complementary acid site mechanisms in hydrogen-free polyethylene upcycling: elucidating the distinct roles of Brønsted and Lewis sites in Ce-modified zeolites (DOI: 10.1039/D5GC01799H).

Read our interview with the corresponding author Prof. Insoo Ro below.

Could you briefly explain the focus of your article to the non-specialist? We show a way to upcycle waste polyethylene into useful liquid fuels (naphtha-range hydrocarbons) without adding external hydrogen. The key is a cerium-modified zeolite catalyst in which Brønsted acid sites cut polymer chains, while strong Lewis acid sites draw hydrogen from the plastic itself to complete the reactions. In tests, we achieved full conversion with high selectivity to valuable liquids and processed common post-consumer plastics.

How would you set this article in a wider context?

Most advanced plastic-to-fuel methods still depend on fossil-derived hydrogen. By clarifying how Brønsted and strong Lewis acid sites can work together to use the plastic’s own hydrogen, our study outlines a hydrogen-free route that could lower cost and carbon intensity and offers a design framework extendable to other difficult plastics.

What is the motivation behind this work?

We aimed to remove the hidden hydrogen and noble-metal costs from polyolefin upcycling and answer a mechanistic question: can Lewis acid sites actively drive hydrogen transfer under hydrogen-free conditions? Our results indicate they can—and quantify their impact.

What aspects of this work are you most excited about at the moment and what do you find most challenging about it?

I’m excited that we can tune the acid-site balance to push selectivity to valuable liquids while suppressing coke. Key challenges now are scale-up in continuous flow, handling mixed/contaminated waste streams, and maintaining site proximity and strength over long times on stream.

What is the next step? What work is planned?

We will (i) Translate the chemistry into continuous reactors and regeneration protocols; (ii) optimize site proximity and mesostructure to stabilize strong Lewis sites; (iii) extend hydrogen-free concepts to mixed polyolefins and difficult feeds; and (iv) complete techno-economic and life-cycle assessments with partners.

Please describe your journey to becoming an independent researcher

I received my B.S. from Rice University and Ph.D. from the University of Wisconsin–Madison, followed by postdoctoral research at UC Santa Barbara. I started my independent group in 2020 and am now an Associate Professor at Korea University.

Can you share one piece of career-related advice or wisdom with other early career scientists?

Write your “mechanism of impact” as early as you write your experimental plan—what changes if you’re right, and who cares. It keeps projects focused, eases collaboration, and helps you avoid distracting side paths.

Why did you choose to publish in Green Chemistry?

The journal’s mission aligns with our goal of lowering the carbon and resource footprints of plastics upcycling. Green Chemistry also reaches a community where mechanistic catalysis and sustainability meet, and the Emerging Investigators Series offers timely visibility with rigorous peer review.

Meet the author

Insoo Ro is an Associate Professor of Chemical and Biological Engineering at Korea University. He received his B.S. from Rice University and Ph.D. from the University of Wisconsin–Madison, followed by postdoctoral research at UC Santa Barbara. His group studies heterogeneous catalysis for sustainable plastics upcycling and CO2-to-fuels chemistry, with an emphasis on site-specific catalyst design and operando characterization.