Two novel Pb(II) coordination polymers (CPs) based on 4-(4-oxopyridin1(4H)-y1) and 3-(4-oxopyridin-1(4H)-y1) phthalic acid: Band gaps, structures, and their photoelectrocatalytic properties in CO2-saturated

摘要

Based on 4-(4-oxopyridin-1(4H)-y1) phthalic acid (H2L1) and 3-(4-oxopyridin-1(4H)-yl) phthalic acid (H2L2),two novel Pb(II) coordination polymers (CPs) formulated as [Pb4Cl4 center dot(L-1)(2 center dot)H2O] (CP 1), [Pb3Cl4 center dot L-2 center dot H2O](n) (CP 2) were solvothermally synthesized and characterized by single-crystal X-ray diffraction. The two novel Pb(II) CPs (CPs 1 and 2) possessed different structures. Density functional theory (DFT) calculations revealed the two CPs had different band structures yet the characteristic of semiconductors in common. Their valence band (VB) and conduction band (CB) positions were determined by Mott-Schottky and UV-visible diffuse reflectance analyses. The photoelectrocatalytic performance of the two CPs towards CO2 reduction were tested by photocurrent responses at various applied potentials. And the E =-1.4 V vs SCE (-0.74 V vs NHE) was selected as the required potential according to the regulation of photocurrent responses at various tested potentials in CO2-saturated system. The photoelectrocatalytic performance of CP 2 was superior to that of CP 1 owing to the well-matched CB position of CP 2 and CO2 reduction potentials at the required potential of -1.4 V vs SCE (-0.74 V vs NHE). In addition, the photoelectrolytic experiment were performed 1 h in the CO2-saturated 0.2 M Na2SO4 solution at the required potential of -1.4 V vs SCE (-0.74 V vs NHE) with and without illumination, and we initially demonstrated the influence of visible light in the CO2-saturated photoelectrocatalytic measurement system and the reason of stability in 1 h chronoamperometry.