Molten-salt-mediated synthesis of Na+ doped Bi4TaO8Cl nanosheets with exposed {001} facets for enhanced photocatalytic degradation

Regulating the exposed surfaces of semiconductors is believe to be a versatile strategy to boost their photoactivity. Herein, the Na + doped Bi 4 TaO 8 Cl (BTOC) nanosheets with the exposed {001} active faces were synthesized via a facile molten salt method. The size of BTOC nanosheets could be readily tuned by controlling the feeding content of the molten salts (NaCl and KCl). Benefited from the cooperative effect of the Na + doping and the exposed active {001} facets, the optimal BTOC-24 nanosheets exhibited high photoactivity. Under 5 W white LED light irradiation, the degradation rates of BTOC-24 nanosheets for ofloxacin (OFL) and Rhodamine B (RhB) were 84.1% and 97.3%, which were drastically enhanced by 2 and 6-folds than that of bulk BTOC, respectively. The mechanism for the improved photoactivity was also investigated. This work demonstrates the synergetic effect of engineering the thickness and exposed crystal face towards the enhanced photoactivity of 2D BTOC, which also shows significant implications for designing other 2D semiconductor nanosheet with efficient environmental remediation performance. • Size and exposed facets of BTOC nanosheets were controlled by molten salt method. • Ultrathin BTOC-24 nanosheets exhibited superior photocatalytic activity. • The high proportion of {001} exposed facets expedited electron transport. • The main reactive species for the photocatalytic mechanism were discussed.