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

Abstract

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 μmol·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.