Constructing Z‐scheme β‐Bi 2 O 3 /ZrO 2 heterojunctions with 3D mesoporous SiO 2 nanospheres for efficient antibiotic remediation via synergistic adsorption and photocatalysis

Abstract A series of Z‐scheme β‐Bi 2 O 3 /ZrO 2 heterojunction composites containing three‐dimensional (3D) mesoporous silica nanospheres (MSNs) were synthesized as efficient catalysts for antibiotic remediation. The obtained MSN/β‐Bi 2 O 3 /ZrO 2 ternary composites possess novel lamellar cross structure, which is well constructed by β‐Bi 2 O 3 nanosheets, 3D MSNs, and ZrO 2 nanoparticles. The optimal sample BZS‐2 (Bi: Zr: Si = 1: 0.4: 0.33) shows an adsorptive‐photocatalytic removal efficiency of 92.7% towards levofloxacin (LVF) and a total organic carbon (TOC) removal efficiency of 60.0% under simulated solar light irradiation for 100 min. BZS‐2 can also remove 90.1% and 91.2% of tetracycline hydrochloride (TC) and oxytetracycline hydrochloride (OTC), respectively, and the maximum adsorption capacity of TC over BZS‐2 is almost 10 times that of β‐Bi 2 O 3 . The improvement of photocatalytic activity can be mainly attributed to the enhanced visible‐light adsorption capacity and more efficient separation of photogenerated electron–hole pairs. A possible Z‐scheme photocatalytic mechanism of β‐Bi 2 O 3 /ZrO 2 heterojunctions based on valence band offset (Δ E VBO ) and conduction band offset (Δ E CBO ) is proposed. This study provides an efficient way to construct novel mesoporous ternary photocatalyst with increased accessible surface area and active sites for treatment of antibiotics by synergistic adsorption and photocatalysis.