Synergistic effect of NiO-loaded gold NPs modified exfoliated graphitic carbon nitride (E-gC₃N₄) with the role of hot electrons and hole scavengers for boosting solar hydrogen production

The photocatalytic hydrogen production capabilities of a well-designed NiO–Au loaded exfoliated graphitic carbon nitride (E-gC₃N₄) were evaluated after it was synthesized in a straightforward, template-free, single-step process. This study delves into the synergistic impact of utilizing exfoliated g-C₃N₄ (E-gC₃N₄) loaded with NiO to trap electrons and plasmonic Au to elevate solar-driven H₂ evolution through the surface plasmon resonance effect. Using 2 % NiO/E-gC₃N₄ and 0.3 % Au/E-gC₃N₄ samples, the H₂ yield of 2620 and 2725 μmol g⁻¹, were obtained, which were 25 and 26 folds higher than using bulk g-C₃N₄, respectively. The highest photocatalytic H₂ production of 4750 μmol g⁻¹ was obtained with 1 % NiO-0.3 % Au/E-gC₃N₄, which was 1.74, 1.81 and 45.24-fold more than it was produced with 0.3 % Au/E-gC₃N₄, 2 % NiO/E-gC₃N₄ and bulk g-C₃N₄ samples, respectively. Increased visible light absorption and charge production due to the SPR effect of Au and efficient charge separation due to NiO co-catalyst led to an increase in H₂ generation. The composite was also stable for the consecutive four cycles, in which continuous H₂ evolution was obtained. This novel strategy offers promise for synthesizing effective composites for visible-light-driven H₂ evolution.