High-Efficiency Photocatalytic Ammonia Synthesis by Facet Orientation-Supported Heterojunction Cu2O@BiOCl[100] Boosted by Double Built-In Electric Fields

In this work, the advantages of in situ loading, heterojunction construction, and facet regulation were integrated based on the poly-facet-exposed BiOCl single crystal, and a facet-oriented supported heterojunction of Cu2O and BiOCl was fabricated (Cu2O@BiOCl[100]). The photocatalytic nitrogen reduction reaction (pNRR) activity of Cu2O@BiOCl[100] was as high as 181.9 μmol·g–1·h–1, which is 4.09, 7.13, and 1.83 times that of Cu2O, BiOCl, and Cu2O@BiOCl-ran (Cu2O randomly supported on BiOCl). Combined with the results of the photodeposition experiment, X-ray photoelectron spectroscopy characterization, and DFT calculation, the mechanism of Cu2O@BiOCl[100] for pNRR was discussed. When Cu2O directionally loaded on the [100] facet of BiOCl, electrons generated by Cu2O will be transmitted to the [100] facet of BiOCl through Z-scheme electron transmission. Due to the directional separation characteristics of charge in BiOCl, the electrons transmitted from Cu2O are enriched on the [001] facet of BiOCl, which will together with the original electrons generated by pristine BiOCl act on pNRR, thus greatly improving the activity of photocatalytic ammonia synthesis. Thus, a new construction scheme of biphasic semiconductor heterojunction was proposed, which provides a reference research idea for designing and synthesizing high-performance photocatalysts for nitrogen reduction.