Highly dispersed platinum-anchored g-C3N4 nanotubes for photocatalytic hydrogen generation

Abstract

To overcome the shortcoming of rapid recombination of photoexcited electron-hole pairs of g-C3N4, noble metals are usually loaded as co-catalyst. However, conventional chemical reduction often brings about the loading of noble metal aggregates or nanoparticles that leads to a low atomic utilization efficiency. In this work, Pt atoms are highly dispersed on S-doped g-C3N4 nanotubes through in situ pyrolysis of H2PtCl6. Diffuse reflection infrared Fourier transform spectrum and XPS spectrum reveal that Pt exists in the state of +2 chemical valence and is anchored by coordination with diatomic N and S of g-C3N4, leading to a high dispersion and stabilization of Pt atoms in g-C3N4 nanotube. The optimal H2 production rate (0.3 wt% Pt) is 5304 μmol h−1g−1 and the turnover frequency (TOF) is 321.7 h−1 upon visible light illumination (λ > 420 nm), that is 3.2 times as high as Pt nanoparticle loaded g-C3N4 nanotube with the same loading content. Our work provides a new way to anchor noble metal on photocatalyst via diatomic coordination and enhance the atomic utilization efficiency of noble metal co-catalyst. Moreover, the unique electronic structure of Pt2+ with electron-deficient 5d orbitals decreases the kinetic energy barrier and promotes H2 evolution on the surface of photocatalyst.