• While humble copper (Cu) may not boast the allure of gold or silver, its remarkable versatility makes it invaluable in cutting-edge research. A collaborative effort by scientists from Tohoku University, the Tokyo University of Science, and the University of Adelaide has unveiled a method to enhance the selectivity and sustainability of electrochemical CO2 reduction processes. • By engineering the surfaces of Cu nanoclusters (NCs) at the atomic level, the team has unlocked new possibilities for efficient and eco-friendly carbon conversion technologies. This breakthrough not only showcases the transformative potential of Cu in sustainable chemistry, but also highlights the critical impact of global collaboration in addressing pressing challenges like carbon emissions. • Electrochemical CO2 reduction reactions (CO2RR) have garnered significant attention in recent years for their potential to transform excess atmospheric CO2 into valuable products. Among the various nanocatalysts studied, NCs have emerged as a standout due to their distinct advantages over larger nanoparticles. • Within this family, Cu NCs have shown great promise, offering formation of variable products, high catalytic activity, and sustainability. Despite these advantages, achieving precise control over product selectivity at an industrial scale remains a challenge. As a result, current research is intensely focused on refining these properties to unlock the full potential of Cu NCs for sustainable CO2 conversion. • "To achieve this breakthrough, our team had to modify NCs at the atomic scale," explains Professor Yuichi Negishi of Tohoku University, "However, it's very challenging since the geometry of the NCs was heavily dependent on the precise parts that we needed to alter. It was like trying to move a supporting pillar of a building." Representation of the Faradic Efficiency of the CO2 reduction products of different Cu NC samples • They successfully synthesized two Cu14 NCs with identical structural architectures by altering the thiolate ligands (PET: 2-phenylethanethiolate; CHT: cyclohexanethiolate) on their surfaces. Overcoming this limitation required the development of a carefully controlled reduction strategy, which enabled the creation of two structurally identical NCs with distinct ligands—a significant step forward in NC design. • However, the team observed variations in the stability of these NCs, attributed to differences in intercluster interactions. These disparities play a crucial role in shaping the sustainability of these NCs during catalytic applications. • Although these NCs share nearly identical geometries derived from two different thiolate ligands, they demonstrate markedly different product selectivity when their catalytic activity for CO2 reduction was tested. These variations impact the overall efficiency and selectivity of the CO2RR. • Negishi concludes, "These findings are pivotal for advancing the design of Cu NCs that combine stability with high selectivity, paving the way for more efficient and reliable electrochemical CO2 reduction technologies."

• University of Central Florida (UCF) researcher Debashis Chanda, a professor at UCF's NanoScience Technology Center, has developed a new technique to detect long wave infrared (LWIR) photons of different wavelengths or "colors." • The new detection and imaging technique will have applications in analyzing materials by their spectral properties, or spectroscopic imaging, as well as thermal imaging applications. • Humans perceive primary and secondary colors but not infrared light. Scientists hypothesize that animals like snakes or nocturnal species can detect various wavelengths in the infrared almost like how humans perceive colors. • Infrared, specifically LWIR, detection at room temperature has been a long-standing challenge due to the weak photon energy, Chanda says. • LWIR detectors can be broadly classified into either cooled or uncooled detectors, the researcher says. • Cooled detectors excel in high detectivity and fast response times but their reliance on cryogenic cooling significantly escalates their cost and restricts their practical applications. • In contrast, uncooled detectors, like microbolometers, can function at room temperature and come at a relatively lower cost but exhibit lower sensitivity and slower response times, Chanda says. • Both kinds of LWIR detectors lack the dynamic spectral tunability, and so they can't distinguish photon wavelengths of different "colors." • Chanda and his team of postdoctoral scholars sought to expand beyond the limitations of existing LWIR detectors, so they worked to demonstrate a highly sensitive, efficient and dynamically tunable method based on a nanopatterned graphene. • Tianyi Guo is the lead author of the research. Guo completed his doctoral degree at UCF in 2023 under Chanda's mentorship. This newly discovered method is the culmination of the research that Guo, Chanda and others in Chanda's lab have performed, Chanda says. • "No present cooled or uncooled detectors offer such dynamic spectral tunability and ultrafast response," Chanda says. "This demonstration underscores the potential of engineered monolayer graphene LWIR detectors operating at room temperature, offering high sensitivity as well as dynamic spectral tunability for spectroscopic imaging." • The detector relies on a temperature difference in materials (known as the Seebeck effect) within an asymmetrically patterned graphene film. Upon light illumination and interaction, the patterned half generates hot carriers with greatly enhanced absorption while the unpatterned half remains cool. The diffusion of the hot carriers creates a photo-thermoelectric voltage and is measured between the source and drain electrodes. • By patterning the graphene into a specialized array, the researchers achieved an enhanced absorption and can further electrostatically tune within the LWIR spectra range and provide better infrared detection. The detector significantly surpasses the capabilities of the conventional uncooled infrared detectors—also known as microbolometers. • "The proposed detection platform paves the path for a new generation of uncooled graphene-based LWIR photodetectors for wide ranging applications such as consumer electronics, molecular sensing.

• Ammonia is the fuel for fertilizers and is also a high-energy, CO2-emitting ammonia. Researchers at the University of Illinois Chicago (UIC) with RMIT University Melbourne are advancing project-based innovative cleaner and cost-effective approaches to ammonia production. Rethinking the Haber-Bosch process for solving ammonia’s carbon problem • Ammonia production presently involves the Haber-Bosch process, which is energy and hydrogen intensive; quite a large part of hydrogen derives from fossil fuels. Such characteristics make the ammonia industry an excellent contributor to global CO2 emissions. • A new method-lithium-mediated ammonia synthesis (LMAS) was devised and developed by the team at the University of Illinois Chicago. The main process involves using the lithium electrode in conducting reactions with nitrogen and hydrogen. • This makes temperature processes unnecessary. What really makes it different compared to others is that LMAS has the potential of drastically reducing production costs. Traditional green ammonia, for instance produced from renewable hydrogen, tends to be expensive, with prices ranging from $750 to $888 for every tonne produced. • The LMAS technology could as much as reduce this price by up to 60%, making it possible to produce ammonia for as little as $450 per tonne. This is as gigantic a boon as one can expect, especially because the key constituent used in the whole thing-the ethanol-is massively produced and relatively cheap. • This however is still very promising technology and has some critiques when it comes to cost reductions because it is debatable whether the technology would prove itself more efficient and economically sound in the long run than claimed. Liquid metal catalyst of RMIT: Ammonia production reversed • Out here in the rest of the world, researchers at RMIT University in Melbourne are inventing a radically different concept of ammonia production. They built a liquid metal catalyst from copper and gallium for the first time for ammonia synthesis. • The ‘nano planets’ work well at lower pressure and temperature levels compared to the traditional ones since they only require 4 bars pressure and a temperature of 400 degrees C rather than the usual 200 bars and 500 degrees C. • The research shows that the method requires 20% less heat and 98% less pressure than conventional ammonia production (such as this one which is to be produced in America), which would be a great potential for energy savings. The catalyst is so efficient in splitting nitrogen and hydrogen that it allows for production on a very large scale while keeping the carbon footprint much smaller. • The process can play a very important role in the hydrogen economy, enabling ammonia to become a much safer and efficient carrier for hydrogen storage and transport. In the future, this could allow green energy to be sold rather than wasted in conversion losses associated with long-distance energy transportation. From fertilizers to fuel: Ammonia of the future • Indeed, the ramifications of these two technologies may go beyond ammonia production. Ammonia is intended to serve an important future role as a clean shipping fuel since, it can be converted into hydrogen for use on-demand. • Apart from the liquid metal catalyst of RMIT and LMAS, they offer pathways to a more sustainable future for ammonia-reliant industries through reducing the carbon footprint associated with ammonia production. The real test, however, would be to scale these technologies up to satisfy global demand. • The lifecycle emissions of the lithium-based LMAS technology have yet to be determined, along with issues of efficiency and scalability of both methods. Nonetheless, both teams are actively improving their respective technologies. They are in collaboration with industry partners exploring the pathways of commercialization. • These cutting-edge processes in ammonia production, which rely on lithium-mediated synthesis and liquid metal catalysis, have the potential to revolutionize energy consumption, cost, and CO2 emission. They could, however difficult, contribute greatly to decarbonizing industries and make an important contribution to that most forward-looking and hopeful future (like the one discovered in a 20-million-year-old mine in Finland).