Photocatalytic CO2 reduction over Nb2O5/basic bismuth nitrate nanocomposites. (January 2021)

• Record Type: Journal Article
• Authors: Oliveira, Jéssica A.; Torres, Juliana A.; Gonçalves, Renato V.; Ribeiro, Caue; Nogueira, Francisco G.E.; Ruotolo, Luís A.M.
• Is Part Of: Materials research bulletin. Volume 133(2021)
• Publication Date: 2021-01
• Subjects: A. Composites -- A. Nanostructures -- A. Semiconductors -- B. Chemical synthesis -- D. Catalytic properties; Materials -- Periodicals; Crystal growth -- Periodicals; Matériaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Crystal growth; Materials; Periodicals; 620.11
• DOI: 10.1016/j.materresbull.2020.111073
• Languages: English
• ISSNs: 0025-5408

Abstract

Graphical abstract: Highlights: Nb2 O5 /basic bismuth nitrate nanocomposites formed a Z-scheme. Different hydrothermal conditions lead to different crystalline structures. Nb2 O5 /basic bismuth nitrate nanocomposites are promising photocatalysts. The Z-scheme mechanism allows a spatial separation of the charge carriers. CO and C2 H4 were detected as the main products of CO2 photoreduction. Abstract: In this work, CO2 was photocatalytic converted to valuable chemicals using photoactive basic bismuth nitrates (Bi6 O(4+ x ) (OH)(4- x ) (NO3 )(6- x ) ). n H2 O, x = 0–2, n = 0–3) and niobium pentoxide nanocomposites (BBN/Nb2 O5 ). Milder hydrothermal synthesis (at 120 °C) maintained the crystal lattice of the BBN precursor (Bi6 O5 (OH)3 (NO3 )5 .3H2 O), while the synthesis carried out at 230 °C led to lamellar Bi2 O2 (OH)(NO3 ). Despite of the sample treated at 230 °C did not present the required band edge positions to reduce CO2, all the other materials were active for CO2 photoreduction. CO (∼2.8 μmol g −1 h −1 ) was identified as the main product, followed by C2 H4 (∼0.1 μmol g −1 h −1 ), with the latter being favored using the nanocomposite produced at 120 °C. Scavenger experiments revealed that the photocatalytic mechanism is based on a Z-scheme, where molecules are oxidized in the valence band of Nb2 O5 and CO2 is reduced in the conduction band of BBN.