Fig 1

(a) Schematic showing the synthesis processes of modulation of PCN framework structures via molten salt polarization. (b) LiCl/KCl phase diagram, the positions marked with asterisks in the diagram indicate the molten salt system conditions (specifically referring to the temperature and component ratio of the LiCl/KCl system) for modulation of PCN framework structures. (c) XRD spectra of PCN and LKCN0.95 and LKCN-0.2. (d) C 1s XPS spectra, and (e) N 1s XPS spectra of PCN and PCN with distinct framework structures tailored via molten salt polarization."

Fig 2

(a) FT-IR spectra of PCN, LKCN-0.95 and LKCN-0.2. (b) 13C solid-state NMR spectra of PCN, LKCN-0.95 and LKCN-0.2. (c) SAED and (d) HR-TEM image and (e) lengths of 10 lattice spacings of LKCN-0.95. (f) SAED and (g) HR-TEM image and (h) lengths of 10 lattice spacings of LKCN-0.2. (i) Structure diagram of LKCN-0.95. (j) Structure diagram of LKCN-0.2."

Fig 3

(a) Photocatalytic H2O2 production rates of PCN, LKCN-0.95 and LKCN-0.2. (b) A performance comparison of artificial H2O2 photosynthesis from various sacrificial agent content (v/v, Table S4). 5 recycles stability test of LKCN-0.95 (c) and LKCN-0.2 (d). Apparent quantum efficiency (AQE) of H2O2 production as a function of irradiation wavelength for LKCN-0.95 (e) and LKCN-0.2 (f)."

Fig 4

(a) UV-visible diffuse reflection spectra for PCN, LKCN-0.95 and LKCN-0.2. (b) Tauc plots of PCN, LKCN-0.95 and LKCN-0.2 determined by the Kubelka-Munk formula from the original UV-visible diffuse reflection spectra. (c) VB-XPS and (d) band structure alignments of PCN, LKCN-0.95 and LKCN-0.2. (e) PL emission spectra of PCN, LKCN-0.95 and LKCN-0.2. (f) Transient photocurrent curves of PCN, LKCN-0.95 and LKCN-0.2 that were measured in 0.1 mol L−1 Na2SO4 aqueous solution."

Fig 5

Surface potential images in the absence of light for PCN (a), LKCN-0.95 (d) and LKCN-0.2 (g). Surface potential images in the presence light for PCN (b), LKCN-0.95 (e) and LKCN-0.2 (h). CPD profiles across PCN (c), LKCN-0.95 (f) and LKCN-0.2 (i) before and after irradiation."

Fig 6

2D contour plots of fs-TAS recorded at indicated delay times measured with 400 nm excitation: PCN (a) and LKCN-0.2 (d). Femtosecond transient absorption spectra of PCN (b) and LKCN-0.2 (e). Corresponding transient absorption kinetic traces of PCN (c) and LKCN-0.2 (f) within 1000 ps and (inside) parameters derived from fitted kinetics."

Fig 7

In situ FT-IR spectra of PCN (a), LKCN-0.95 (b) and LKCN-0.2 (c) exposed to water vapor and O2 then recorded under visible light irradiation for 30 min. (d) O2-TPD of PCN, LKCN-0.95 and LKCN-0.2. (e) DMPO–•O2- EPR for PCN, LKCN-0.95 and LKCN-0.2. (f) Koutecky-Levich plots of PCN, LKCN-0.95 and LKCN-0.2."

Fig 8

The calculated structure model of PCN (a), LKCN-0.95 (b) and LKCN-0.2 (c). Calculated charge density difference of PCN (d), LKCN-0.95 (e) and LKCN-0.2 (f). (g) Energy profiles for the oxygen activation reaction over different framework structures (melon, heptazine and heptazine-triazine). (Inset) Schematic illustrations of the reaction processes (side view): A1–A3 for PCN, B1–B3 for LKCN-0.95, and C1–C3 for LKCN-0.2, respectively."

Fig 9

Photocatalysis mechanism scheme for H2O2 photosynthesis on LKCN-0.2."