MOF-Decorated Rod-Shaped BiVO4 Heterostructures: Mutual Charge Transfer System Concerning Superior Photocatalytic Efficacy for Bromoxynil Breakdown and H2 Generation Process

The high cost of noble metals and the poor performance of non-noble-metal catalysts in scaled applications continue to be obstacles to percolate photocatalysis for producing hydrogen and degrading pollutants. Recently, non-novel metal–organic frameworks (MOFs) have received substantial interest as sacrificial templates to improve photocatalytic performance. Here, MOF-decorated non-novel metal oxide heterostructure photocatalyst is described with superior catalytic and optoelectrical properties. Through a simple hydrothermal process, a series of three-dimensional microrod mediator-free Mg-MOF-74/BiVO4 heterojunction photocatalysts were successfully produced. The morphology and composition show that the composite heterojunction materials have microrods of BiVO4 (2–4 μm) with sparsely dispersed MOF spikes. For photocatalytic H2 evolution and bromoxynil degradation efficiency, 1/4th wt % MOF decoration on BiVO4 stands out among other combinations. The superior carrier separation and movement between the Mg-MOF-74 and BiVO4 is considered as the main root of improved photocatalytic performance, which was further confirmed by time-resolved fluorescence spectra and photoelectrochemical measurements. Based on the results of free radical scavenging activity and EPR measurements, the heterostructures comply with a standard Z-scheme charge transfer mechanism instead of a typical Type-II heterojunction. The MOF-decorated heterostructure (25-MOF/BVO) demonstrated increased photocatalytic efficacy for bromoxynil degradation having a rate constant of 3.5 × 10–2 min–1.