Covalently Bonded Bi₂O₃ Nanosheet/Bi₂WO₆ Network Heterostructures for Efficient Photocatalytic CO₂ Reduction

The highly efficient spatial carrier separation and abundant active sites are significant for CO2 photocatalytic reduction efficiency. Herein, an ultrathin Bi2O3 nanosheet/Bi2WO6 network heterostructure is successfully synthesized via a covalently bonded epitaxial growth strategy. Due to cosharing of the Bi-O tetrahedron between Bi2O3 and Bi2WO6, this heterostructure exhibits a compact interface, which can provide a highway for the charge transfer and then boost their separation. Moreover, the pores generated from the hierarchical structure afford abundant exposed photocatalytic active sites. Thus, the optimal Bi2O3/Bi2WO6 heterostructure (BOBWO-12) shows superior photocatalytic performance for CO2 reduction with an ultrahigh selectivity as well as the removal of RhB. Notably, the photocatalytic CO generation rate over BOBWO-12 reaches up to 17.39 mu mol.g(-1).h(-1), which is 18.0 and 4.2 times higher than that of bulk-Bi2WO6 and Bi2WO6 nanosheets, respectively, and the selectivity is of about 95.4%. Moreover, the Bi2O3/Bi2WO6 heterostructure also exhibits improved long-term stability, resulting from the firm heterointerface. Our studies present a conventient avenue to construct a high-efficiency heterostructure photocatalyst with a firm interface by the covalently bonded epitaxial growth method for CO2 reduction.