We developed a dual-strategy of Fe doping and CeO₂ decoration to optimize the electronic structure and reaction energy barrier of Ni₂P to achieve energy-efficient and chlorine-free hydrogen production by coupling the HER with HzOR in seawater.

The ZnCo2O4/Tm:Bi2O3 quantum dots/SrTiO3 transparent perovskite pn junction is synthesized via the approach of a hybrid chemical-sol-gel-annealing method. The as-prepared ZnCo2O4/Tm:Bi2O3 QDs/SrTiO3 shows high transmittance of ∼87%–90%, an obvious photoelectric enhancement of ∼2.3 × 103 folds than that of ZnCo2O4/SrTiO3, and good stability in 6 months. The interfacial Tm:Bi2O3 QDs modification is deemed to be the core issue. In addition to Fermi level regulation and barrier transition for carrier transportation, the Tm:Bi2O3 QDs with high quantum yield can maintain high transparency and increase carrier injection for balancing transparency and power conversion efficiency (PCE), meanwhile achieving ultraviolet light conversion for wide bandgap semiconductor excitation via upconversion of Tm-doping, including Co2+/Co3+ induced hole, thereby promoting carrier dynamics transportation for high transparency-PCE.

A transparent pn junction in CuGaO2/La(Ni0.2Fe0.2Co0.2Cr0.2Zn0.2)O3 QDs/BaTiO3 is prepared via the hydrothermal-sol-gel approach. The obtained CuGaO2/LaCrHEO QDs/BaTiO3 pn junction achieves a high transmittance of ∼85%–90%, a remarkable photoelectric enhancement of ∼3.1 × 103-fold compared to intrinsic CuGaO2/BaTiO3, and a good stability in 6 months. In this system, the interfacial modification of LaCrHEO QDs is deemed as the core issue, because besides appropriate Fermi level/high QY, it owns the charge inducing/injecting/driving via B-site Ni–Fe–Co–Cr–Zn polymetallic ionic metastable state coupling can heighten the carrier kinetics transportation to maintain PCE-transparency balance, including Cu+/Cu2+ hole inducing. Additionally, the CuGaO2 nanoarray can improve interfacial contact and maintain good physical/mechanical stability in practical applications, while enhancing solar utilization.