Fabrication of 0D/1D/2D ZnS–CuS nanodots/GNRs/g-C3N4 heterojunction photocatalyst for efficient photocatalytic overall water splitting

Photocatalytic water splitting has become a significant challenge in modern chemistry. In this process, the rate-determining step is the hydrogen evolution reaction (HER). In the present work, a surface modification approach for graphitic carbon nitride (g-C3N4) was applied to improve its photocatalytic HER. 0D ZnS–CuS nanodots were synthesized with the hydrothermal method as a co-catalyst to enhance the capability and stability of water splitting in the presence of visible light irradiation. Also, graphene nanoribbons were synthesized from CNTs unzipping to reduce the energy barrier of HER, improve the HE kinetic, and enhance the catalytic performance of the g-C3N4. By using ZnS–CuS/GNRs(2)/g-C3N4 photocatalyst, a low onset potential of 130 mV, slight Tafel slope of 41 mV dec−1, as well as excellent stability of 2000 s was obtained in acidic media. This efficient performance is attributed to the increased visible light absorption level in the proposed photocatalyst and the high stability in electron-hole pairs.