Enhanced photocatalytic H2 production performance of CdS hollow spheres using C and Pt as bi-cocatalysts

Photocatalytic H2 production from water splitting is an effective method to solve energy crisis and environmental pollution simultaneously. Herein, carbon@CdS composite hollow spheres (C@CdS-HS) are fabricated via a facile hydrothermal method using porous carbon hollow spheres (C-HS) as the template. The C@CdS-HS shows an excellent photocatalytic H2-generation rate of 20.9 mmol h−1 g−1 (apparent quantum efficiency of 15.3% at 420 nm), with 1.0 wt% Pt as a cocatalyst under simulated sunlight irradiation; this rate is 69.7, 13.9, and 3.9 times higher than that obtained with pure CdS hollow spheres (CdS-HS), C@CdS-HS, and CdS-HS/Pt, respectively. The enhanced photocatalytic H2-evolution activity of C@CdS-HS/Pt is due to the synergistic effect of C and Pt as the bi-cocatalyst. The C-HS serves not only as an active site provider but also as an electron transporter and reservoir. Moreover, C-HS has a strong photothermal effect that is induced by near infrared light, which kinetically accelerates the H2-production reaction. Additionally, the underlying charge transfer pathway and process from CdS to C−HS is revealed. This work highlights the potential application of C-HS-based nanocomposites in solar-to-chemical energy conversion.