Effect of Pt–Pd hybrid nano-particle on CdS's activity for water splitting under visible light

Abstract

This paper focuses on the bi-metal co-catalyst of CdS in hydrogen generation from water-splitting under visible light. Pt–Pd eutectic alloy NPs was prepared by two-step chemical reduction, and was subsequently loaded on the surface of CdS photo-catalyst by photo-induced electrons when water splitting reaction was occurring under 300 W Xe light (λ > 420 nm). According to the experimental results, the photo-activity is significantly promoted as bi-metal modified on the surface of CdS. The H2 evolution rate of Pt–Pd/CdS, 25.28 mmol/h/gCat., is ca. 2.4 times as much as that of Pt/CdS, and 3.8 times as much as that of Pd/CdS. HRTEM/ED/EDS revealed that the so-obtained Pt–Pd hybrid NPs with a particle size of 5–8 nm is of similar twin structure. XPS revealed that the as-prepared Pt–Pd bi-metal NPs mainly composed of metallic Pt0 and Pd0. UV–Vis diffuse reflectance spectrum of CdS nanoparticles interpreted its trait in visible light adsorption, and PL lifetime indicated that the high active of Pt–Pd/CdS lies in its high separation efficiency.