ABSTRACT
A series of P-CdS@P-MWOx (M = Ni, Mn, Co, Zn, Fe, Cu) hybrid photocatalysts was constructed using different transition metal polyoxometalates [SiW11M(H2O)O39]n- as precursors via a pyrolysis-phosphidation strategy. Under visible light irradiation (λ = 420 nm), P-CdS@P-NiWOx shows a good H2 evolution rate of 418.4 µmol g-1 h-1 and an AQE of 29.9% at 420 nm without adding a sacrificial reagent, which is a nearly 140-fold enhancement over CdS. This study provides a feasible strategy for designing efficient photocatalysts with highly active facets and heterostructure.
ABSTRACT
The development of new dual functional photocatalysts is highly desirable for conversion and storage of solar energy. Herein, we first constructed hierarchical structure MIL-100(Fe)@BiVO4 in situ growing MIL-100(Fe) nanoparticles (NPs) on the surface of decahedron BiVO4 under mild hydrothermal conditions. The as-synthesized hybrid nanostructure is unambiguously determined using a series of characterization methods. These results demonstrate that the ultra-tiny MOF MIL-100(Fe) particles are immobilized on the surface of decahedron BiVO4 and the composite exhibits a strong interaction between BiVO4 and MIL-100(Fe). This hybrid material MIL-100(Fe)@BiVO4 is employed as a photocatalyst for water oxidation reaction and demonstrates higher O2 production activity in comparison with bare BiVO4. The best performance obtained at the optimal mass percentage of MIL-100(Fe) (8.0 wt %) reaches 333.3 µmol h-1 g-1 of the O2 evolution rate irradiated with visible light, which is almost 4.3 times higher than bare BiVO4 (77.3 µmol h-1 g-1). The enhanced water oxidation performance is due to the more efficient interfacial electron-hole transfer between MIL-100(Fe) and BiVO4, which is verified by the results of various photo-electrochemical characterizations. Moreover, the as-prepared composite MIL-100(Fe)@BiVO4 also displays excellent stability for visible-light-driven water oxidation. This study affords a rational strategy for the controllable construction by loading metal-organic frameworks on a semiconductor surface, which is a good reference for other artificial photosystems.
ABSTRACT
An attractive photoanode material, WO3 , has suffered from its limited visible-light absorption and sluggish surface reaction kinetics, as well as poor stability in neutral electrolytes. Herein, a NiFe/CQD/WO3 composite photoanode was designed and fabricated, with loading of carbon quantum dots (CQDs) and electrodeposition of NiFe layered double hydroxide. The NiFe/CQD/WO3 photoanode obtained a photocurrent density of 1.43â mA cm-2 at 1.23â V vs. reversible hydrogen electrode, which is approximately three times higher than that of bare WO3 . During the test period of 3â h, the stability of WO3 was improved substantially after the loading of cocatalysts. Furthermore, mechanistic insights of the favored band structure and beneficial charge-transfer pathway elucidate the high photoelectrochemical performance of the NiFe/CQD/WO3 composite photoanode.
