Semiconductor‐based Photoanodes Modified with Metal‐Organic Frameworks and Molecular Catalysts as Cocatalysts for Enhanced Photoelectrochemical Water Oxidation Reaction

Abstract

Photoelectrochemical (PEC) water splitting is a promising approach to convert inexhaustible solar energy to hydrogen energy. In this system, the semiconductor is a crucial part as photoelectrode to harvest the solar light and achieve water splitting on the surface. For the surface modification of semiconductor, cocatalyst loading is an effective method to improve the sluggish reaction kinetics. Due to the specific structure of their organic ligands, the metal‐organic frameworks (MOFs) or molecular catalysts as cocatalysts can provide more reaction sites and overcome the interface recombination between semiconductors and cocatalyst layers. The inorganic metal species derived from the MOFs or molecular catalysts also possess porous structures. This review summarizes the recent developments of MOFs and molecular catalysts as well as their derivatives modifying several representative semiconductors for PEC water oxidation reaction. The synthesis methods and performance enhancements are discussed. Finally, this review addresses remarks on current existing changes and perspectives for the further development.

Surface Engineering of BiVO4 Photoanodes for Photoelectrochemical Water Splitting: Recent Advances

“…[40,41,42,43] Additionally, BiVO 4 electrodes are recognized as suitable electrode materials for the OER in PEC water splitting systems owing to their high light absorption, economic viability, and large availability. [44,45] In PEC water splitting, low electronic conductivity, higher charge recombination, and slow oxidation kinetics limit its effectiveness. [46] For wide application of BiVO 4 photoanodes in PEC water splitting, it is essential to overcome their shortcomings.…”

“…Among the most significant photoanode materials for PEC, and other forms of energy conversion, BiVO 4 , an n‐type semiconductor, has emerged in recent decades [40,41,42,43] . Additionally, BiVO 4 electrodes are recognized as suitable electrode materials for the OER in PEC water splitting systems owing to their high light absorption, economic viability, and large availability [44,45] . In PEC water splitting, low electronic conductivity, higher charge recombination, and slow oxidation kinetics limit its effectiveness [46] .…”

Photoelectrochemical water oxidation by a MOF/semiconductor composite

“…Recently, a number MOF/ semiconductor composite lms have been studied, with some eye towards water oxidation. [21][22][23] However, the previously studied approaches utilize MOFs as a doping agent, catalyst, or host for an encapsulated species rather than an incorporated molecular catalyst platform. [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] To our knowledge, the work presented herein, is the rst to explore MOF-incorporated molecular-catalysts semiconductor composites, including detailed work of the operative charge transfer pathways.…”