Incorporating Transition-Metal Phosphides Into Metal-Organic Frameworks for Enhanced Photocatalysis

Metal-organic frameworks (MOFs) have been shown to be an excellent platform in photocatalysis. However, to suppress electron-hole recombination, a Pt cocatalyst is usually inevitable, especially in photocatalytic H(2)production, which greatly limits practical application. Herein, for the first time, monodisperse, small-size, and noble-metal-free transitional-metal phosphides (TMPs; for example, Ni2P, Ni12P5), are incorporated into a representative MOF, UiO-66-NH2, for photocatalytic H(2)production. Compared with the parent MOF and their physical mixture, both TMPs@MOF composites display significantly improved H(2)production rates. Thermodynamic and kinetic studies reveal that TMPs, behaving similar ability to Pt, greatly accelerate the linker-to-cluster charge transfer, promote charge separation, and reduce the activation energy of H(2)production. Significantly, the results indicate that Pt is thermodynamically favorable, yet Ni2P is kinetically preferred for H(2)production, accounting for the higher activity of Ni2P@UiO-66-NH(2)than Pt@UiO-66-NH2.