Future prospects of gold nanoclusters in hydrogen storage systems and sustainable environmental treatment applications

Gold nanoclusters (AuNCs), with sizes below 2 nm, have emerged as remarkable nanomaterials exhibiting unique optical, electronic, and chemical properties. Their ultra-small size imparts advantageous characteristics, including high surface area, tunable fluorescence, and excellent biocompatibility, making AuNCs highly promising for diverse applications. This article explores recent advancements in leveraging AuNCs to address critical challenges in clean energy storage and environmental remediation. For energy storage, AuNCs boost the performance of Li-based batteries by facilitating rapid electron transfer kinetics and limiting polysulfide shuttling. The review delves into mechanistic insights governing AuNC-hydrogen interactions, various synthetic approaches for tailoring AuNCs, and their emerging applications as advanced electrodes, efficient catalysts, and conductive additives enabling improved charge storage capabilities. Additionally, using plasmonic effects and hot carrier generation induced by AuNCs shows tremendous potential in photocatalytic water splitting for clean hydrogen fuel production. For environmental applications, AuNCs enable the degradation of persistent organic pollutants, heavy metal ion detection at part-per-trillion levels, and solar-driven water purification, relying on plasmon-enhanced hot carrier processes. However, the long-term ecological impacts of AuNCs remain unclear. This study thus underscores the need for further toxicological assessments and life cycle analyses to promote sustainable AuNC-based technologies through responsible research and innovation. Overall, it highlights the versatile applicability of AuNCs in addressing critical energy and environmental challenges.