Synergistic effect of adsorption and photocatalysis of BiOBr/lignin-biochar composites with oxygen vacancies under visible light irradiation

Sulfated lignocellulose nanofibril supported flower-like BiOBr with oxygen vacancies towards absorption–photocatalytic synergetic removal of organic pollutants

“…Notably, the introduction of SLCNFs improved the absorption of visible light, and the absorption edge of BiOBr/SLCNF red-shifted to 700 nm, which was due to the increase of oxygen vacancies in BiOBr/SLCNF. 40 Moreover, the band gap of samples was calculated as follows:( αhν ) n = A ( hν − E g )where α , hν , E g and A are the adsorption coefficient, photonic energy, band gap, and constant, respectively. The value of n was chosen to be 1/2.…”

“…Notably, the introduction of SLCNFs improved the absorption of visible light, and the absorption edge of BiOBr/SLCNF red-shifted to 700 nm, which was due to the increase of oxygen vacancies in BiOBr/SLCNF. 40 Moreover, the band gap of samples was calculated as follows:…”

“…42 For instance, Yang et al employed a hydrothermal method to synthesize BiOBr/ lignin-biochar composites containing oxygen vacancies, which degraded 99.2% of RhB within 60 minutes. 40 Creating oxygen vacancies on the surface of a photocatalyst is a typical surface defect engineering method, and it is an efficient strategy to improve the photocatalytic activities. 43 Moreover, as an electron capture center, oxygen vacancies can improve the adsorption and activation of oxygen and the transfer of charge to the reactants.…”

“…43 Moreover, as an electron capture center, oxygen vacancies can improve the adsorption and activation of oxygen and the transfer of charge to the reactants. 40,44 Importantly, LCNFs combine the advantages of lignin and NC, exhibit better performance than NC, and have enormous potential as a photocatalyst carrier material. In a previous study, our research group prepared a new type of lignocellulose nanofibrils/TiO 2 composite aerogel.…”

“…The organic capping molecules of lignin can control the nucleation and growth of crystals, which regulates the morphology of photocatalysts induced by surface ligands. 40 Wang et al , for instance, synthesized BiVO 4 –C photocatalysts with bead shape to improve the photocatalytic activity of the composites using lignin as a regulator. 41 In addition, due to the very low surface energy of Bi–O in BiOX, lignin can interact with the Bi–O bonds to produce a good deal of oxygen vacancies on the BiOX surface.…”