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

Abstract

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.