A novel calcined Bi2WO6/BiVO4 heterojunction photocatalyst with highly enhanced photocatalytic activity

• Novel visible-light-sensitive calcined Bi2WO6/BiVO4 heterojunction photocatalyst was synthesized through a two-step method.
• C-Bi2WO6/BiVO4 exhibits a wide visible-light absorption performance and well crystallinity.
• C-Bi2WO6/BiVO4 shows a high photocatalytic activity in the degradation of RhB.
• C-Bi2WO6/BiVO4 has a high stability and long-time reusability.
• The photocatalytic mechanism is proposed and holes and hydroxyl radicals are the two main reactive species for RhB degradation.

In this study, a novel visible-light-sensitive calcined Bi2WO6/BiVO4 (C-Bi2WO6/BiVO4) heterojunction photocatalyst was synthesized via a hydrothermal process followed by the calcination at 600 °C. The as-prepared multilayer C-Bi2WO6/BiVO4 photocatalyst was composed of Bi2WO6 and BiVO4 with a good visible-light absorption performance. Experimental results showed that C-Bi2WO6/BiVO4 exhibited higher photocatalytic activity than C-Bi2WO6, C-BiVO4, and uncalcined Bi2WO6/BiVO4, and the degradation efficiency of Rhodamine B (RhB) could achieve 100% within 30 min. In addition, after six recycles for the photodegradation of RhB, C-Bi2WO6/BiVO4 did not exhibit significant loss of photocatalytic activity, confirming its stability and long-time reusability. The photocatalytic mechanism was studied by active species trapping experiments, revealing that the holes (h+) and hydroxyl radicals (OH) played key roles in RhB degradation. Moreover, on the basis of the calculated energy bands, the obviously enhanced photocatalytic performance can be attributed to the efficient separation of photoinduced electron–hole pairs. In addition, the calcination improved the crystallinity of C-Bi2WO6/BiVO4, combined with the excellent photoabsorption ability further improved its photocatalytic activity. The present study provides a new strategy to design composite photocatalysts with enhanced photocatalytic performance for water purification and other applications.

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