NiB as a Substitute for the Pt Cocatalyst in CdS with Enhanced Visible-Light Photocatalytic H2 Production

It is necessary to find a low-cost cocatalyst as a substitute for Pt in the CdS-based photocatalytic area. Hence, NiB was proposed to replace Pt for high H2 production. CdS@NiB presented an excellent H2 generation rate of 28,112 μmol h–1 g–1 (λ > 420 nm), which was 11 and 5.7 times higher than that of CdS and CdS@Pt, respectively. Different characterization methods (e.g., electron paramagnetic resonance, photoluminescence spectra, photoelectric responsiveness, etc.) proved that the synergistic effect between NiB and CdS could improve the photogenerated charge carrier separation of CdS. According to density functional theory results, a strong electronic coupling effect between CdS and NiB induced more electrons to participate in H2 production. When adsorbed with H2O, the d-band center of Ni atoms in CdS@NiB shifted from −1.84 to −1.96 eV, leading to the migration of more electrons across the Fermi level. From the electron density redistribution in CdS@NiB–H2O, the electron transfer path of NiB → CdS → H2O was achieved, which could extend the H–O bond of H2O from 0.975 to 0.986 Å and increase the H–O–H bond angle from 104.274 to 105.365°, thereby activating H2O and promoting H2 production.