Superior synergy of g-C3N4/Cd compounds and Al-MOF-derived nanoporous carbon for photocatalytic hydrogen evolution

Graphitic carbon nitride (gCN) exhibits outstanding photocatalytic performances toward H2 evolution. However, it can be further improved by overcoming its disadvantages such fast recombination of pohotogenerated electron-hole pairs. Here, we propose an efficient photocatalysts based on three components: (i) gCN modified with (ii) cadmium compounds (CdX: Cd(OH)2, CdS, CdO) and (iii) nanoporous carbon flakes (NPC) derived from Al-metal organic framework. The fabrication method was focused on finding the optimal hybrid composition dispalying the most powerful performance. Three main aspects were revealed: (i) band gap of gCN narrowing from 2.70 eV to 2.32 eV, (ii) reduction of overpotential for H2 evolution, as conduction band minimum (CBM) moved from −1.07 V vs. NHE to −0.63 V vs. NHE and (iii) enhanced charge separation, since CdX and NPC acted as electron acceptors. These factors had an effect on ˜60-fold enhancement of the photocatalytic efficiency. The mechanism of the photocatalytic process was discussed.