Effect of surface ligands on the photocatalytic hydrogen production of Cu nanoclusters

• Published in: International journal of hydrogen energy Vol. 116; pp. 279 - 287
• Main Authors: Busi, Kumar Babu, Majji, Manikanta, Sai Krishna, Ambati Mounika, Ball, Writoban Basu, Dalapati, Goutam Kumar, Motapothula, Mallikarjuna Rao, Chakrabortty, Sabyasachi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 04.04.2025
• Subjects: Copper nanoclusters; Hydrogen evolution; Large surface-to-volume ratio; Photocatalysis; Water splitting; Water splitting; Large surface-to-volume ratio; Copper nanoclusters; Photocatalysis; Hydrogen evolution
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2025.03.106

In this study, tiny sized (∼2 nm) copper nanoclusters (Cu NCs) were synthesized with strong optical response, where red/green emitting features were observed using protein/amino acid as surfactant molecules. The photocatalytic water splitting reactions for both ligand-mediated Cu NCs were carried out in a photochemical reactor under solar simulator for 12 h. Interestingly, protein mediated red colour emitting Cu NCs produced stable H2 ∼ 256 mmol g−1 and the solar to hydrogen efficiency (STH) is approximately ∼ 0.5% while comparing with green emitting Cu NCs with 86 mmol g−1 and STH of 0.08%. These interesting results were achieved due to their longer lifetime, strong colloidal stability, high quantum yield and rich surface functionalization features. These were further confirmed through absorption spectroscopy, fluorescence spectroscopy, time-resolved photoluminescence, zeta potential, high resolution transmission electron microscopy and X-ray photoelectron spectroscopy analytical techniques. Thus, these inexpensive Cu NCs could be used as alternate photocatalysts for H2 production than obviating the usage of precious noble metal platinum-based ones. A typical illustration of atomically precised copper nanoclusters employed as a potential nanocatalysts to produce green hydrogen under the illumination of solar simulator as light source. [Display omitted] •Stable atomically precise Cu NCs were synthesized for photocatalysis.•Red/green emitting Cu NCs were achieved using BSA/l-cysteine acid as surfactant.•Photocatalytic water splitting was demonstrated for H2 production.•BSA-mediated Cu NCs produced 256 mmol g−1 H2, higher than l-cysteine (86 mmol g−1).•Protein (BSA) as surfactants improved stability, and photocatalytic performance.