Multifunctional Bi₂O₂(OH)(NO₃) Nanosheets with {001} Active Exposing Facets: Efficient Photocatalysis, Dye-Sensitization, and Piezoelectric-Catalysis

Exploration for multiresponsive catalytic materials and synthesis of highly active exposing crystal facets are challenging subjects for catalysis research. In this work, well-defined Bi 2 O 2 (OH)(NO 3 ) nanosheets (BON-S) with a dominantly exposed {001} active facet were synthesized by a sodium-dodecyl-benzenesulfonate-assisted (SDBS-assisted) soft-chemical route. BON-S presents far superior photocatalytic activity compared to bulk materials as well as a universal performance for degradation of contaminants and antibiotics under UV light. The profoundly enhanced photocatalytic activity basically stems from the largely shortened diffusion pathway of photogenerated electrons (e – ) and holes (h + ), favoring their migration from bulk to the surface of the catalyst under the internal electric field between [Bi 2 O 2 (OH)] + and NO 3 – layers along the [001] direction. The photocatalytic active species production rates of BON-S are determined to be 3.14 μmol L –1 min –1 for superoxide radicals ( • O 2 – ) and 0.03 μmol L –1 min –1 for hydroxyl radicals ( • OH). BON-S also shows an enhanced visible-light-responsive dye-sensitization degradation activity with Rhodamine B (RhB) as a sensitized medium to provide photoinduced e – . Moreover, for the first time we unearth that Bi 2 O 2 (OH)(NO 3 ) demonstrates an ultrasonic-assisted piezoelectric-catalytic performance for decomposition of methyl orange, bisphenol A, and tetracycline hydrochloride, and • OH dominates the piezoelectric-catalytic process with an evolution rate of 7.13 μmol L –1 h –1, which far exceeds the photocatalytically induced one. This study may cast new inspiration on developing a new microstructure-design strategy for high photocatalytic/dye-sensitization performance, and furnishes a novel piezoelectric-catalytic material for environmental applications.