Enhanced photocatalytic hydrogen evolution by S-scheme heterojunction and metal phosphide in NiTiO3/Graphdiyne.

A key strategy to improve photocatalytic reaction efficiency is to achieve effective separation and migration of photo-generated carriers. Heterojunctions and co-catalysts are essential for boosting charge separation and transfer, reducing activation energy, and providing active sites for surface redox reactions. Herein, we introduce a composite catalytic system based on NiTiO 3 , enhanced with Graphdiyne (GDY) and NiP, achieving a hydrogen production activity of 8.37 mmol g−1 h−1. This performance is attributed to the combined effects of S-scheme heterojunction formation and NiP nanoparticle generation through phosphorylation. The S-scheme heterojunction effectively separates electron-hole pairs, reducing charge transport distance. Additionally, NiP nanoparticles formed in situ promote faster charge separation from NiTiO 3 and act as active sites to accelerate the reduction half-reaction. Consequently, NiTiO 3 /GDY-P exhibits higher light absorption, faster charge separation, and superior redox capacity compared to NiTiO 3. This work presents an efficient, eco-friendly multiphase catalytic system based on an S-scheme heterojunction and metal phosphide. • GDY was prepared by a new method of ball milling HEB-TMS. • GDY and NiTiO 3 construct S-scheme heterojunction to enhance electron-hole separation. • NiP nanoparticles boost NiTiO 3 's photoinduced electron transfer, enhancing charge separation. • In-situ XPS and DFT calculations proved the charge transfer process of NiTiO 3 /GDY-P. [ABSTRACT FROM AUTHOR]