Constructing nano CdS-decorated porous biomass-derived carbon for multi-channel synergetic photocatalytic hydrogen evolution under solar lighting

Abstract

Developing noble-metal-free photocatalysts for boosting photocatalytic hydrogen evolution reaction (HER) under solar lighting has long been desired. In this work, hierarchical heteroarchitectures comprised of zero-dimensional (0D) hexagonal CdS nanoparticles (NPs) with 60 nm in size decorating onto 3D porous biomass-derived carbon (PBC) honeycomb-like architectures are fabricated by a microwave-assisted aqueous chemical reaction, where PBC is derived from the agriculture discarded bagasse. The significantly boosted photocatalytic hydrogen generation of CdS/PBC composite is ascribed to the multi-channel synergetic effect on the heteroarchitectures with the closely interfacial connection, as a result of increasing the wide-spectrum solar absorption, promoting the photoinduced charges migration rate, and accelerating kinetically the mass-transfer efficiency by the photothermal effect. The H2-evolving efficiency over the optimal CdS/PBC-3 achieves 14.67 mmol∙g−1∙h−1 under simulated solar irradiation, which is 43.1 times higher than that of pure CdS counterpart. The maximum apparent quantum efficiency over CdS/PBC-3 is 22.68% at 420 nm. The step-scheme (S-scheme) electron transfer pathway for CdS/PBC is proposed based on the band energy alignments. This work develops a new way to fabricate non-precious biochar composites for efficient conversion of solar energy in photocatalysis.