Dual-functional　photocatalysts　(DFP)　have　shown　remarkable　advantages　in　converting　solar　energy　into　renewable　H2　while　simultaneously　remediating　the　environmental　pollution.　To　achieve　rapid　separation　and　high　utilization　of　the　photogenerated　charge　carriers,　it　is　crucial　to　establish　robust　atom-level　interactions　within　a　DFP　heterostructure.　In　this　context,　a　binary　Ni2P/ds-Zn3In2S6　photocatalyst　was　synthesized　for　synchronous　norfloxacin　degradation　and　H2　production.　Metallic　Ni2P　was　chemically　anchored　onto　the　ds-　Zn3In2S6　surface　to　reduce　the　energy　barrier　for　interfacial　electron　transfer.　Sulfur　vacancies　were　engineered　within　the　Zn3In2S6　lattice　to　facilitate　the　isolation　of　charge　carriers.　Resultantly,　the　composite　photocatalyst,　leveraging　the　synergistic　effects　of　the　Ni2P　cocatalyst,　interfacial　Ni-S　bond-reinforced　ohmic　junctions　and　sulfur　defects,　exhibited　19.17-fold　enhancements　in　H2　release　(2.32　mmol　g−1　h−1)　and　2.84-fold　improvements　in　norfloxacin　decomposition　(98.38%)　compared　to　pristine　Zn3In2S6.　On　the　ground　of　Fukui　function　calculations　and　liquid　chromatography-mass　spectrometry　results,　four　plausible　pathways　for　photocatalytic　norfloxacin　degradation　were　proposed.　It　is　anticipated　that　the　collaborative　strategy　outlined　in　this　work　will　provide　valuable　insights　into　the　design　of　high-performance　DFP.　©　2025　Elsevier　Ltd