Uniform CdS-decorated carbon microsheets with enhanced photocatalytic hydrogen evolution under visible-light irradiation

Abstract

Large-scale production of clean and renewable fuels is crucial for satisfying the world's energy needs, and hydrogen evolution via photo-driven water splitting stands as a prime candidate to fill this need. In present work, we converted carbonized poplar catkins (CPC) microtubes into microsheets by ultrasonic crushing and subsequently deposited CdS nanoparticles on the microsheets to synthesize the CdS/carbon (CdS/CPC) photocatalyst for photo-driven hydrogen evolution. The carbon microsheets were ∼160 nm thick and 1–20 μm wide in dimensions, and CdS nanoparticles with a diameter of ∼20 nm were homogeneously dispersed on the microsheets. The CdS/CPC composites showed a higher visible-light absorption and larger photocurrent density compared with pure CdS. The as-prepared composites exhibited excellent photocatalytic activity for water splitting, and the H2-evolution rate was up to 5367 μmol g−1 h−1, approximately 7.8 times that of pure CdS. Moreover, CdS/CPC-2 can retain 93.8% of its original H2-evolution rate after 4-cycle continuous catalyzing last for 16 h. The extremely high activity of CdS/CPC can be attributed to its lower interfacial charge-transfer resistance and the effective separation of photo-induced electrons because of two-dimensional structure. A combination of low-cost production and excellent photocatalytic H2-evolution demonstrates the potential application of bio-derived carbon-based microsheets for noble-metal-free photocatalyst.