Abstract
Photocatalysis is a green technology for tackling water and air contamination. A valid alternative to the most exploited photocatalytic material, TiO2, is bismuth oxyhalides, which feature a wider bandgap energy range and use visible radiation to attain photoexcitation. Moreover, their layered structure favors the separation of photogenerated electron–hole pairs, with an enhancement in photocatalytic activity. Controlled doping of bismuth oxyhalides with metallic bismuth nanoparticles allows for further boosting of the performance of the material. In the present work, we synthesized Y%Bi-doped BiO(Cl0.875Br0.125) (Y = 0.85, 1, 2, 10) photocatalysts, using cetyltrimethylammonium bromide as the bromide source and varying the chloride source to assess the impact that both length and branching of the hydrocarbon chain might have on the framing and layering of the material. A change in the amount of the reducing agent NaBH4 allowed tuning of the percentage of metallic bismuth. After a thorough characterization (XRPD, SEM, TEM, UV-DRS, XPS), the photocatalytic activity of the catalysts was tested in the degradation of NOx under visible light, reaching a remarkable 53% conversion after 3 h of illumination for the material prepared using cetylpyridinium chloride.
Highlights
Water and air pollution has become a worldwide concern as it affects humans, flora, and fauna
Since the main participant of ambient pollution is ozone, as it forms through the photochemical oxidation of volatile organic compounds (VOCs) and carbon monoxide (CO) in the presence of nitrogen oxides (NOx) [28], we investigated the activity of our catalysts by degrading NOx under visible light, reaching a remarkable 53% conversion after 3 h of illumination for the catalyst prepared using CPC
The relative intensity of the peaks in the BiOClx Br(1−x) patterns is affected by the morphology of the composite catalyst
Summary
Water and air pollution has become a worldwide concern as it affects humans, flora, and fauna. Air pollution kills about 3 million people a year [1]. Water pollution accounts for unknown long- and short-term effects on both aquatic life and human health [2] and restricted access to safe water causes more than 1.6 million deaths annually [3]. In the last 20 years, photocatalysis has been applied to a wide variety of fields, from the environment [4,5,6], to the building industry [7], and energy-related areas [8] to biomedical specialties. The absorption of a photon of proper energy by a semiconductor promotes an electron from the valence band to the conduction band, which in turn creates an electron vacancy (hole) in the valence band. The electron–hole pairs can either recombine or take part in a chemical reaction that involves surface-adsorbed species
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