Carbon quantum dots conjugated with metal hybrid nanoparticles as advanced electrocatalyst for energy applications – A review

The recent advances in nanomaterials have led to speculation about the effectivity of carbon quantum dots applied as electrocatalysts for water splitting. An insufficient amount of research has been undergone into this proposed application, although CQDs exhibit great potential with rapid electron transfer rates, long-term stability and desirable morphologies. To evaluate various materials that could aid CQDs in their application as electrocatalysts for water splitting, investigate environmentally conscious synthesis routes and determine whether the application could be considered for commercial applications, numerous studies and articles were collated to obtain a comprehensive strategy for processing and analysing data. Further, investigating not only CQDs but metal alloy nanoparticles, along with their current uses and the other supporting materials they have been conjugated with, contributes to the significance to this work. Focusing on the extrapolated results of over potentials, current densities and production rates of both hydrogen and oxygen throughout electrolysis is of utmost importance. Notably, CQDs exhibited low Tafel slopes (35–45 mV/dec), along with crucial traits such as stability and rapid electron transfer rates, affirming their potential as electrocatalysts. Among the various metal alloy nanoparticles investigated, suitable candidates for conjugation were identified. Collectively, the collated data suggests that a CQD/metal alloy nanoparticle conjugation could enhance the water splitting process for commercial applications, particularly in the underexplored realm of hydrogen production. However, it remains imperative to perform experimental procedures to substantiate this proposition when feasible.