Ni₂P-Modified P-Doped Graphitic Carbon Nitride Hetero-Nanostructures for Efficient Photocatalytic Aqueous Cr(VI) Reduction

Abstract

Targeting heterostructures with modulated electronic structures and efficient charge carrier separation and mobility is an effective strategy to improve photocatalytic performance. In this study, we report the synthesis of 2D/3D hybrid heterostructures comprising P-doped graphitic carbon nitride (g-C3N4) nanosheets (ca. 50–60 nm in lateral size) and small-sized Ni2P nanoparticles (ca. 10–12 nm in diameter) and demonstrate their prominent activity in the photocatalytic reduction of Cr(VI). Utilizing a combination of spectroscopic and electrochemical characterization techniques, we unveil the reasons behind the distinct photochemical performance of these materials. We show that Ni2P modification and P doping of the g-C3N4 effectively improve the charge-carrier transportation and spatial separation through the interface of Ni2P/P-doped g-C3N4 junctions. As a result, the catalyst containing 15 wt.% Ni2P exhibits superior photocatalytic activity in the detoxification of Cr(VI)-contaminated effluents under UV-visible light illumination, presenting an apparent quantum yield (QY) of 12.5% at 410 nm, notably without the use of sacrificial additives. This study marks a forward step in understanding and fabricating cost-effective photocatalysts for photochemical applications.

Keywords

• nickel phosphide
• graphitic carbon nitride
• hetero-nanostructures
• photocatalysis
• Cr(VI) reduction
• environmental remediation