Synergistic effect of gold NPs modified graphitic carbon nitride nanotubes (g-CNT) with the role of hot electrons and hole scavengers for boosting solar hydrogen production

Abstract

The efficient and selective photocatalysts for the evolution of hydrogen are highly demanding, however, many semiconductors are complex in nature and have lower photocatalytic efficiency. This is because of their small exposed surface area, poor light penetration, and unregulated charge recombination rate. Herein, well-designed graphitic carbon nitride with hierarchical nanotextures loaded with plasmonic gold (Au) nanoparticles has been investigated for stimulating photocatalytic H2 evolution. Hole scavengers, diffusion effects, duration, and mass transfer were used to evaluate the photoactivity activity in a slurry type continuous flow photoreactor system. Due to better charge carrier separation and enhanced light permeability, H2 evolution was boosted by two times when bulk g-C3N4 structure was alternated with graphitic carbon nitride nanotubes (g-CNT). The maximum H2 generation rate was 455 μmol g−1 h−1 with 0.3% Au/g-CNT nanotexture, which was 17.8 and 8.9 times greater than utilizing g-C3N4 and g-CNT samples, respectively. The key factors influencing this improvement in photoactivity were the unique interlayer opening, higher light penetration, more light utilization due to plasmonic effect, enhanced surface reactive active sites, and decreased charge carrier recombination. The hot electrons due to plasmonic gold was another important feature to promote H2 evolution rate under solar energy. It is possible to employ these freshly developed nanotextures, which have a gold plasmonic effect, for solar energy conversion and other energy-related applications.