Abstract:
Selective production of value-added chemicals using
biomass-derived platform chemicals is a sustainable and effective way to
fulfil the demands for chemicals around the globe. Photocatalytic biomass
conversion is an economical, green, and sustainable process to address the
environmental problems caused by the consumption of fossil fuel-derived
chemicals and energy sources. In this research work, three Bi-based oxides,
Bi2WO6, BiVO4, and Bi2MoO6, are employed as photocatalysts, and their
activities are compared in selective oxidation of two important
lignocellulose-derived chemicals, 5-hydroxymethylfurfural (HMF) and
vanillyl alcohol (VOL). Among these oxides, the rose-like Bi2WO6
nanostructured photocatalyst exhibits the highest catalytic activity and
selectively produces 2,5-diformylfuran and vanillin from HMF and VOL.
These materials are thoroughly characterized by several techniques (powder X-ray diffraction, X-ray photoelectron spectroscopy, and
scanning electron microscopy) to understand the cause of their different physicochemical properties and photocatalytic activities.
N2-sorption measurement, DR-UV−visible analysis, pyridine Fourier transform infrared, and photoelectrochemical measurements
indicate a large surface area, an appropriate band gap, high surface acidity, and better migration and separation of the photogenerated
charge carriers in Bi2WO6 than in BiVO4 and Bi2MoO6, resulting in higher photocatalytic activity over Bi2WO6. The Bi2WO6 catalyst
exhibits excellent activity under an artificial light source (λ > 420) and very good activity under the sunlight. The structure-activity
relationship is established using catalytic activity data, physicochemical characterization, and scavenging studies. The scavenging
studies suggest that the photogenerated holes (h+
), electrons (e−), and superoxide radicals (O2
•−) play key roles in achieving high
photocatalytic activity. The synthesized photocatalyst exhibits remarkable photostability and recyclability. This research work will
motivate researchers and scientists to develop sustainable, cost-effective, and environmentally benign catalytic processes for efficient
utilization of sunlight and lignocellulose biomass conversion into energy and value-added chemicals.
