Fig 1

(a) Synthetic process of g-C3N4/ZnIn2S4 (CN/ZIS); (b) SEM image of the In-MOF; (c) SEM image of ZIS; (d) TEM image of CN/ZIS-0.1; (e) HRTEM image of CN/ZIS-0.1; (f) EDX mapping images of CN/ZIS-0.1."

Fig 2

(a) Nitrogen adsorption-desorption curve and (b) corresponding pore size distribution curve of CN, CN/ZIS-0.1 and ZIS; (c) XRD patterns of CN, ZIS and CN/ZIS-0.1; XPS analysis of CN/ZIS-0.1: (d) survey; (e) C 1s, (f) N 1s, (g) Zn 2p, (h) In 3d, (i) S 2p."

Fig 3

(a) Photocatalytic NO removal performance of CN/ZIS-X and ZIS and (b) NO2 concentration vs. irradiation time curve; (c) NO removal rates of different samples; Relative product conversion over a 30 min photocatalytic NO removal reaction for (d) CN and (e) CN/ZIS-0.1; (f) five-cycle stability test of CN/ZIS-0.1 sample; (g) Comparison with the NO oxidation rates of other photocatalysts in recent work [43–59]."

Fig 4

(a) UV-Vis diffuse reflectance spectra of CN, ZIS and CN/ZIS-0.1; (b) band gap calculation maps of CN and ZIS. Mott-Schottky plots of (c) CN and (d) ZIS; Projected density of states of (e) S orbitals in ZIS and CN/ZIS, and (f) C orbitals in CN and CN/ZIS; (g) Photoluminescence spectra of CN and CN/ZIS-0.1; (h) Transient photocurrent response and (i) Electrochemical impedance spectroscopy of CN, ZIS, and CN/ZIS-0.1."

Fig 5

The DFT calculated EWF of (a) CN; (b) ZIS and (c) CN/ZIS; (d) Side projection of the differential charge density along with the planar-averaged differential charge density for CN/ZIS; (e) Schematic representation of the CN/ZIS photocatalytic NO oxidation process; In situ XPS spectra including (f) N 1s; (g) In 3d; (h) S 2p for CN/ZIS-0.1."

Fig 6

(a, b) Effects of various scavengers on NO removal over CN/ZIS-0.1 sample; (c) Charge density difference diagrams, adsorption energies, and Bader charge transfer for the adsorption of *O2 intermediates at the CN and CN/ZIS heterojunctions; (d) Charge density difference diagrams, adsorption energies, and Bader charge transfer for the adsorption of *NO intermediates at the CN and CN/ZIS heterojunctions (The values of equipotential surfaces are all set to 3 × 10−3 electrons per cubic nanometer); The COHP of the bond formed between (e) N in CN/ZIS and O2; (f) C in CN/ZIS and NO; (g) S in CN/ZIS and NO."