• • Optimal PG-QD doping ratio of 15% in wide-band semiconductor composites maximizes hydrogen evolution activity without the suppression typically observed at higher GDY loadings, enabling practical catalyst formulation with reduced precious-metal content.
• • Hydrogen evolution rate of 12.69 mmol g−1 h−1 exceeds that of commercial P25 by over thirty-fold, directly translating to lower levelized cost of hydrogen in solar-driven water splitting.
• • Enhanced Vis-NIR absorption and photothermal conversion suppress charge carrier recombination, increasing quantum efficiency under full-spectrum irradiation and reducing parasitic heat losses in reactor scale-up.
• • PG-QDs mitigate UV competition with wide-band semiconductors, allowing tandem spectral utilization that boosts solar-to-hydrogen conversion efficiency beyond the UV-limited ceiling of TiO2-based systems.