A novel photovoltaic-thermal system based on spectral splitting of nanoparticle suspensions for simultaneous hydrogen production and seawater desalination

Traditional photovoltaic-thermal systems achieve full-spectrum sunlight utilization while producing only low-grade heat. This study reports an efficient PVT system designed for simultaneous hydrogen production and seawater desalination, in addition to high-efficiency electrical output. Specifically, Ag@SiO₂/CoSO₄-PG nanoparticle suspensions with varied loadings were prepared for photothermal and photoelectric conversion. Here, desalinated seawater can be directly utilized for electrolytic hydrogen production driven by photoelectric conversion module. System performance was evaluated across a broad range of conditions. The system exhibits peak photothermal and photoelectric conversion efficiencies of 45.57 % and 15.39 % respectively, when the nanoparticle loading is 80.00 mg/L. Using an 80.00 mg/L nanoparticle suspension filter, the system achieves a peak exergy efficiency of 60.71 % and an economic value enhancement of 75.9 % compared to a PV only system, when the worth factor w is 3. Under optimal operational conditions, the photo-hydrogen conversion efficiency reached 7.82 %. This study demonstrates an effective strategy for full spectrum solar energy conversion to hydrogen using sea water and provides a valuable guidance for future study.