Regulating effect on photocatalytic water splitting performance of g-C3N4 via confinement of single atom Pt based on energy band engineering: A first principles investigation

Photocatalytic overall water splitting is an effective strategy to solve the energy crisis and being global carbon neutral. In this work, the regulating effect of single-atom confinement effect for photocatalytic overall water splitting performance on the g-C3N4 is investigated based on energy band engineering by the spin-polarized DFT calculations. The calculation results indicate that the confined single Pt atoms enhance the photo-response of the g-C3N4 by reducing the band gap of the system rather than introducing the impurity level. Upon the introduction of single Pt atoms confinement in the pristine monolayer g-C3N4, the band energy levels of the system will be modified. Specially, the VBM will become more positive. And, the photocatalytic activity of the g-C3N4, which originally showed photocatalytic inertia to the OER, is activated, so as to provide enough driving force to realize water oxidation. Meanwhile, the confined single-atom Pt can effectively reduce the energy barrier of HER, improve the hydrogen evolution kinetics of the g-C3N4, and enhance the catalytic performance of the g-C3N4. In brief, the confined single-atom Pt not only regulates the photocatalytic OER performance on the g-C3N4, but also further improves its photocatalytic HER performance.