Anchoring single Pt atoms and black phosphorene dual co-catalysts on CdS nanospheres to boost visible-light photocatalytic H2 evolution.

• Decorate black phosphorene onto CdS nanospheres to create BP/CdS heterostructures by a grinding and sonication method. • Anchor Pt single-atoms on BP/CdS heterostructures via a photo-reduction deposition procedure. • Achieve a hydrogen evolution rate that is 96 times greater than that of CdS nanospheres, alongside an AQE of 46% at 420 nm. • Unravel interfacial electronic interactions, photoexcited charge-carrier dynamics and photocatalytic mechanism. • Pave a path to the rational design of viable co-catalysts at the nanoscale and atomic level. [Display omitted] Co-catalysts play a crucial role in semiconductor-based artificial photosynthesis and stabilizing co-catalysts on heterojunction photocatalysts is essential for achieving high photocatalytic efficiency. Herein, we report novel dual co-catalysts of black phosphorene (BP) and single Pt atoms on CdS nanospheres. BP/CdS heterostructures are prepared by grinding and sonication and then single Pt atoms are deposited onto BP/CdS through a photo-reduction procedure. In addition to being anchored on the surface step edges of CdS nanospheres, Pt single-atoms with positive charge are embedded on Cd vacancies and stabilized by Pt-S covalent bonds. Single Pt atoms are immobilized on the surface of BP as well. The as-prepared Pt-BP/CdS composites are evaluated toward visible-light-driven hydrogen generation. In a range of Pt and BP loading contents, 0.5 wt% Pt-5 wt% BP/CdS composites display the greatest photoactivity and outperform pristine CdS nanospheres by a factor of 96 in terms of hydrogen evolution rate, alongside a remarkable apparent quantum efficiency of 46% at 420 nm. In-depth analyses on interfacial electronic interactions and photoexcited charge-carrier dynamics demonstrate that both single Pt atoms and BP strongly interact with CdS and synergistically steer spatial charge separation, thereby boosting photocatalytic performance. This study may pave a path to the rational design of co-catalysts at the nanoscale and atomic level for solar-to-chemical energy conversion and beyond. [ABSTRACT FROM AUTHOR]