Mesoporous Co3O4/In2O3 nanocomposites for formaldehyde gas sensors: Synthesis from ZIF-67 and gas-sensing behavior

Hollow Co3O4/CdS Nanoparticles for Photocatalytic Hydrogen Evolution and Photodegradation

“…Herein, the peaks at 19.04, 31.37, 37.00, 38.73, 44.94, 55.70, 59.42, and 65.30° are ascribed to the (111), (220), (311), (222), (400), (422), (511), and (440) planes of Co 3 O 4 (PDF No. 42-1467), − and demonstrate consistent diffraction peaks at all formed nano pn junctions (Figure ), indicating that the Co 3 O 4 core can maintain good stability during the secondary chemical deposition. Further, a series of new peaks appear at 25.25, 26.82, 28.39, 44.12, and 52.30° of formed nano pn junction, which correspond to the (100), (002), (101), (110), and (112) planes of single CdS (PDF No.…”

“…Herein, the peaks at 19.04, 31.37, 37.00, 38.73, 44.94, 55.70, 59.42, and 65.30°are ascribed to the (111), ( 220), ( 311), ( 222), ( 400), ( 422 20,21,51 Moreover, no apparent FT-IR absorption (Figure S2) manifests that the organic precursor of ZIF-67 has been removed thoroughly. 56,57 As shown, the prepared ZIF-67 precursor with a diameter of ∼300 nm exhibits good dispersibility (Figure 2a). After annealing, a typical Co 3 O 4 ultrathin hollow nanostructure with a diameter of ∼300 nm is composed of many smaller nanoparticles (Figure 2b).…”

“…Corresponding to SEM, the Co 3 O 4 /CdS nano pn junction (Figure a) exhibits a typical ultrathin hollow core–shell nanostructure, especially the thin shell of CdS and the nanoparticle core of Co 3 O 4 can be observed. There, the lattice spacings (Figure b,c) of 0.337 and 0.244 nm are ascribed to the (002) plane of CdS and (311) plane of Co 3 O 4 . − ,− In addition, the corresponding EDX spectra (energy dispersive X-ray, Figure S4) and mappings (Figure d–f) are provided, manifesting the presence of Co, Cd, and S elements, and the hollow core–shell nanostructure of the as-prepared Co 3 O 4 /CdS nano pn junction, owing to the distribution of Co and other components, is symmetrical/hollow.…”

“…77-2306), and indicate the deposition of the CdS shell. − Additionally, due to the thin shell nanostructure, the observed diffraction peaks exhibit apparent broadening. No other obvious peaks indicate the presence of Co mainly as Co 3 O 4 , instead of other mixed Co-based compounds. ,, Moreover, no apparent FT-IR absorption (Figure S2) manifests that the organic precursor of ZIF-67 has been removed thoroughly. , …”

“…Besides adjusting the diameter quantificationally via the ZIF-67 precursor, it can also provide a sufficient Co source for formation of Co-based semiconductor metallic oxide, , while constructing a hollow nanostructure via the simple calcination to decompose organic ligands thoroughly. Guo et al used the ZIF-67 template to construct a Co 3 O 4 /In 2 O 3 mesoporous nanostructure and obtained decent gas-sensing performance, Ding et al prepared the Co 3 O 4 /TiO 2 nano-heterojunction via the ZIF-67 template auxiliary and achieved good water splitting activities . In addition, the Co 2+ /Co 3+ ratio of such a Co-based metallic oxide core can be regulated by the calcination atmosphere so that the carrier dynamic equilibrium can be meet to improve the photocatalytic performance. , Moreover, such ultrathin core–shell nanostructure can shorten the carrier transportation route to accelerate carrier diffusion, which can improve the photocatalytic performance further and inhibit the photocorrosion effectively …”