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.