Growth of NiMn layered double hydroxides on nanopyramidal BiVO4 photoanode for enhanced photoelectrochemical performance

摘要

Photoelectrochemical water oxidation for hydrogen generation via utilizing sunlight is considered a very promising pathway for generating sustainable energy in an environmental manner. Here, a composite photoanode, consisting of nanopyramidal BiVO4 arrays and one layered double hydroxide (NiMn-LDH) was designed and fabricated via a facile route. The obtained BiVO4/NiMn-LDH composite photoelectrode presented a significant enhancement in the photoelectrochemical (PEC) current density, conversion efficiency and stability for solar water oxidation. With 2D NiMn-LDH decoration, an obvious cathodic shift of similar to 480 mV in the onset potential can be observed, and more than two times enhancement in photocurrent performance is achieved. The improvement in photoelectrochemical activity for BiVO4/NiMn-LDH composite photoanode can be attributed to the enhanced water-oxidation kinetics leading to the efficient separation, transfer and collection of charge carriers at the photoanode/electrolyte interface. The result demonstrates NiMn-LDH represents one of the active oxygen evolution catalysts (OECs) to improve the PEC activity of metal oxide photoanode.