Although reports have shown shifts in carbon dot emission wavelengths resulting from varying the excitation wavelength, this excitation-dependent emission does not constitute true tuning, as the shifted peaks have much weaker intensity than their dominant emission, and this is often undesired in real world applications. We report for the first time the synthesis and photoluminescence properties of carbon dots whose peak fluorescence emission wavelengths are tunable across the entire visible spectrum by simple adjustment of the reagents and synthesis conditions, and these carbon dots are excited by white light. Detailed material characterization has revealed that this tunable emission results from changes in the carbon dots' chemical composition, dictated by dehydrogenation reactions occurring during carbonization. These significantly alter the nucleation and growth process, resulting in dots with either more oxygen-containing or nitrogen-containing groups that ultimately determine their photoluminescence properties, which is in stark contrast to previous observations of carbon dot excitation-dependent fluorescence. This new ability to synthesize broadband excitable carbon dots with tunable peak emissions opens up many new possibilities, particularly in multimodal sensing, in which multiple analytes and processes could be monitored simultaneously by associating a particular carbon dot emission wavelength to a specific chemical process without the need for tuning the excitation source.

Negative carbon emission technologies are critical for ensuring a future stable climate. However, the gaseous state of CO 2 does render the indefinite storage of this greenhouse gas challenging. Herein, we created a liquid metal electrocatalyst that contains metallic elemental cerium nanoparticles, which facilitates the electrochemical reduction of CO 2 to layered solid carbonaceous species, at a low onset potential of −310 mV vs CO 2 /C. We exploited the formation of a cerium oxide catalyst at the liquid metal/electrolyte interface, which together with cerium nanoparticles, promoted the room temperature reduction of CO 2 . Due to the inhibition of van der Waals adhesion at the liquid interface, the electrode was remarkably resistant to deactivation via coking caused by solid carbonaceous species. The as-produced solid carbonaceous materials could be utilised for the fabrication of high-performance capacitor electrodes. Overall, this liquid metal enabled electrocatalytic process at room temperature may result in a viable negative emission technology.

Antibiotic resistance has made the treatment of biofilm-related infections challenging. As such, the quest for nextgeneration antimicrobial technologies must focus on targeted therapies to which pathogenic bacteria cannot develop resistance. Stimuli-responsive therapies represent an alternative technological focus due to their capability of delivering targeted treatment. This study provides a proof-of-concept investigation into the use of magneto-responsive gallium-based liquid metal (LM) droplets as antibacterial materials, which can physically damage, disintegrate, and kill pathogens within a mature biofilm. Once exposed to a low-intensity rotating magnetic field, the LM droplets become physically actuated and transform their shape, developing sharp edges. When placed in contact with a bacterial biofilm, the movement of the particles resulting from the magnetic field, coupled with the presence of nanosharp edges, physically ruptures the bacterial cells and the dense biofilm matrix is broken down. The antibacterial efficacy of the magnetically activated LM particles was assessed against both Gram-positive and Gram-negative bacterial biofilms. After 90 min over 99% of both bacterial species became nonviable, and the destruction of the biofilms was observed. These results will impact the design of next-generation, LM-based biofilm treatments.