Accurate additive manufacturing of lightweight and elastic carbons using plastic precursors

Transformative 3D Printing of Carbon-metal Nanocomposites as Catalytic Joule Heaters for Enhanced Ammonia Decomposition

Electrified thermal chemical synthesis plays a critical role in reducing energy consumption and enabling the industrial decarbonization. While Joule heating offers a promising alternative to gas-burning furnace systems by directly heating substrates via renewable energy supply, most approaches can only heat the reactor, not the catalytic sites. This limitation stems from the lack of methods to on-demand create Joule heaters containing in situ loaded catalytic nanoparticles. This work introduces a scalable platform for producing carbonaceous Joule heaters embedded with catalytic nanoparticles from 3D-printed polypropylene precursors, prepared through crosslinking, metal nitration immersion, and pyrolysis steps. Specifically, sulfonate groups on crosslinked PP can bind with metal ions, yielding well-dispersed, nanosized particles within a carbon structure that maintains macroscopic dimensional accuracy throughout the manufacturing. The approach is modular, allowing control over particle size and composition. Structured carbon with in situ loaded nickel nanoparticles demonstrates efficient Joule heating, high catalytic activity, and significantly reduced activation energy for catalytic ammonia decomposition. This work provides an innovative material and manufacturing platform to produce structured, catalytically active Joule heaters for decarbonization of chemical synthesis and energy production.

Laser Upcycling of Hemoglobin Protein Biowaste into Engineered Graphene Aerogel Architectures for 3D Supercapacitors

Graphene aerogels (GAs) with engineered architectures are a promising material for applications ranging from filtration to energy storage/conversion. However, current preparation approaches involve the combination of multiple intrinsically-different methodologies to achieve graphene-synthesis and architecture-engineering, complicating the entire procedure. Here, a novel approach to prepare GAs with engineered architectures based on the laser-upcycling of protein biowaste, hemoglobin, is introduced. Laser scanning achieves graphene-synthesis concurrently with architecture-engineering through the localized graphitization of hemoglobin along the laser-scan path, enabling the direct preparation of engineered GAs. The laser-upcycled GAs are uniquely decorated with fibrous graphitic structures, which significantly improves the surface area. Such structural formation is attributable to the inherent iron content of hemoglobin which leads to the formation of iron-based nanoparticles that catalyze the formation of nano-structured graphene. By leveraging the high electrical conductivity and unique structural morphology, the laser-upcycled GAs are applied as electrodes of symmetrical 3D supercapacitors. The fabricated supercapacitors exhibited a high specific capacitance (≈54.9 F g-1) and excellent cycle stability (≈94% retention), attributable to the laser-engineered architecture facilitating ion diffusion even for thick electrodes. Not only does this study provide a novel approach to prepare GAs with engineered architectures but showcases the potential of laser-upcycling in preparing advanced functional materials for future devices.

Design and Application of Joule Heating Processes for Decarbonized Chemical and Advanced Material Synthesis

Atmospheric CO2 concentrations keep increasing at intensifying rates due to rising energy and material demands. The chemical production industry is a large energy consumer, responsible for up to 935 Mt of CO2 emissions per year, and decarbonization is its major goal moving forward. One of the primary sources of energy consumption and CO2 emissions in the chemical sector is associated with the production and use of heat for material synthesis, which conventionally was generated through the combustion of fossil fuels. To address this grand challenge, Joule heating has emerged as an alternative heating method that greatly increases process efficiency, reducing both energy consumption and greenhouse gas emissions. In this Review, we discuss the key concepts that govern these Joule heating processes including material selection and reactor design, as well as the current state-of-the-art in the literature for employing these processes to synthesize commodity chemicals along with advanced materials such as graphene, metal species, and metal carbides. Finally, we provide a perspective on future research avenues within this field, which can facilitate the widespread adoption of Joule heating for decarbonizing industrial processes.