Construction of ternary Ni2P/ZIF-8/CdS composite for efficient photocatalytic hydrogen production and pollutant degradation: Accelerating separation of photogenerated carriers

Abstract

Constructing heterojunctions for efficient charge separation is a crucial method to boost photocatalytic activity. Initially, zeolitic imidazolate framework-8 (ZIF-8) nanoparticles were synthesized in situ on the surface of cadmium sulfide (CdS) nanoflowers, creating a novel ZIF-8/CdS composite material. Subsequently, a ternary Ni2P/ZIF-8/CdS composite was fabricated for photocatalytic hydrogen production and pollution reduction. The optimally obtained Ni2P/ZIF-8/CdS composites showed excellent photocatalytic efficiency and structural stability under simulated solar light irradiation. The hydrogen production rate of Ni2P/ZIF-8/CdS composite was 21.05 mmol h−1 g−1. Additionally, Ni2P/ZIF-8/CdS degraded malachite green (MG) with 99% efficiency. It was found that the proximity of sulfides to porous MOFs accelerated the separation of light-induced charges. Nickel phosphide (Ni2P) played a vital role in photocatalytic reactions, serving the dual function of capturing photogenerated electrons and accelerating separation of photogenerated carriers. Mechanistic and characterization studies revealed that constructing heterojunction between CdS and ZIF-8 could promote photogenerated carrier transport, enhance the separation efficiency of photogenerated carriers, ultimately improving the photocatalytic hydrogen production performance and degradation efficiency.