Single Pd atoms supported on ultra-thin bismuth tungstate nanosheets with oxygen vacancies as an efficient photocatalyst

Abstract

Efficient and highly selective photocatalysts for NO oxidation remain a great challenge. In this work, single Pd atoms are deposited onto ultrathin bismuth tungstate (UBWO) nanosheets with O vacancies (Pd-V_O-UBWO) by an impregnation combined with calcination method for the first time. The Pd-V_O-UBWO catalysts exhibit efficient and highly selective photocatalytic activity for the degradation of NO. At a NO inlet concentration of 48 ppm, the NO conversion rate using the Pd-V_O-UBWO catalyst is 89.5% within 1 h of visible light irradiation, which is much higher than that of V_O-UBWO (45.7%). Its selectivity for NO conversion to NO_3⁻ ions is 78.5%. Moreover, experimental results show that the introduction of single Pd atoms promotes the generation of O₂˙⁻ and OH˙. Density functional theory calculations indicate that single Pd atoms favor the adsorption and activation of NO on the Pd-V_O-UBWO surface, thus boosting the effective conversion of NO. Furthermore, the Pd-V_O-UBWO catalyst can achieve higher degradation efficiency of Rhodamine B (86.9%) in liquid solution than V_O-UBWO (68.8%).