Incorporating NiCoP Cocatalyst into Hollow Rings of ZnCo-Metal-Organic Frameworks to Deliver Pt Cocatalyst like Visible Light Driven Hydrogen Evolution Activity

In the field of photocatalysis, metal-organic frameworks (MOFs) have emerged as potential photocatalysts owing to their well-defined and tailorable porous structures, high surface areas, and inherent semiconductor-like behavior. However, their photocatalytic H-2 evolution reaction is still limited due to the higher charge recombination rates. Precious metal cocatalysts, such as Pt and Au, are used to suppress electron-hole recombination effects by forming a Schottky junction, but the high cost and scarcity of these metals limit their large-scale applications. Herein, for the first time, we have developed novel ZnCo-MOF hollow rings at room temperature and loaded it with monodispersed transition-metal phosphide (TMPs; NiCoP, FeCoP, Ni2P, CoP) nanoparticles as non-noble-metal cocatalysts for efficient visible light driven H-2 evolution reaction. The as-obtained NiCoP@ZnCo-MOF composite displays significantly improved H-2 production rates as compared to the parent MOF and their physical mixture and offers similar photocatalytic H-2 evolution activity as compared to that of Pt@ZnCo-MOF. This is attributed to efficient n-n heterojunction charge separation and transfer, and rapid H-2 evolution reaction dynamics by the reduction of activation energy by NiCoP cocatalyst. The H-2 production rate of NiCoP@ZnCo-MOF is 8583.4 mu mol h(-1) g(-1), 16 times higher than parent ZCM, and the apparent quantum yield (AQY) is 20.1% at 590 nm, which remained constant for a minimum of 18 h of repeated cycling in the H-2 production without any degradation of the catalyst.