Interfacial elaborating In2O3-decorated ZnO/reduced graphene oxide/ZnS heterostructure with robust internal electric field for efficient solar-driven hydrogen evolution

Coupling Reliable Interfacial Carrier Migration Channels with Visible-Light Response Antennas in ZnO-Based Heterostructure for Ameliorated Photocatalytic Hydrogen Generation

“…To this end, X-ray photoelectron spectroscopy (XPS) was conducted to decipher the origin behind the superior photocatalytic performance of the Cd@C-ZGS. The Zn 2p orbital binding energy spectra of ZnO, ZnS, and Cd@C-ZGS are displayed in Figure a, where the two peaks in the spectra correspond to the binding energies of Zn 2p 1/2 and Zn 2p 3/2 for Zn 2+ . Comparatively, the binding energies of the heterostructure exhibit a slight shift toward higher energies, indicating the successful construction of the ZnO-ZnS heterostructures after the sulfur reaction .…”

“…Based on collected M-S data for ZnO, ZnS, and CdS at different frequencies (Figure c–e), it is clear that ZnO, ZnS, and CdS are n-type semiconductors with flat-band potentials of −0.38, −1.27, and −0.91 V vs Ag/AgCl, respectively. Conventionally, this value for n-type semiconductor is approximately estimated as its conduct band (CB) potential. , As a result, ZnO, ZnS, and CdS exhibit CB potentials of −0.38, −1.27, and −0.91 V, respectively, which are converted to −0.18, −1,07, and −0.71 V vs NHE, respectively, according to E NHE = E Ag/AgCl + 0.197 . Incorporating the bandgap data obtained from K-M transformation, their corresponding valence band (VB) potentials are 3.04, 2.29, and 1.43 V, respectively.…”

“…15,16 As a result, ZnO, ZnS, and CdS exhibit CB potentials of −0.38, −1.27, and −0.91 V, respectively, which are converted to −0.18, −1,07, and −0.71 V vs NHE, respectively, according to E NHE = E Ag/AgCl + 0.197. 15 Incorporating the bandgap data obtained from K-M transformation, their corresponding valence band (VB) potentials are 3.04, 2.29, and 1.43 V, respectively. Referring to the catalyst preparation process, CdS and ZnS are derived from Cd clusters anchored on ZnO as well as the ion-exchange growth of ZnO.…”

“…As depicted in Figure 3a, the distinctive diffraction peaks of the pristine sample are assigned to the (002), (100), (101), ( 102), ( 103), ( 110), (112), and (201) facets of metallic Cd (JCPDS: 05−0674) and the (100), (002), ( 101), ( 102), ( 110), ( 103), (112), and (201) facets of ZnO (JCPDS: 36− 1451). 15,28 No distinctive characteristic peaks of metallic Zn (JCPDS:04−0831) are found, suggesting that the Cd-induced electrochemical nanoreactors accomplish the growth of Cd clusters during the conversion of Zn powder. 29 Slight peaks centered at 18.86°, 29.49°, 35.22°, 38.17°, 48.96°, 52.31°, 56.09°, 61.17°, 64.62°, 66.57°, 67.10°, and 74.44°related to the (001), ( 100), ( 101), ( 002), ( 102), ( 110), ( 111), (200), The coarse surface of Zn dust is due to slight oxidation.…”

“…The migration of carriers is governed by the carrier transfer kinetics, which directly affects the smooth occurrence of the redox reaction and the STH efficiency . As a result, the carrier behavior at the interfaces of heterostructures attracts a great deal of attention, specifically in artificial photosynthesis systems based on the Z-scheme pathway, where spatial separation of reduction and oxidation reactions can be achieved. − The spatial dissociation of the oxidation and reduction sites is achieved by rational nanospace assembly of materials with staggered band structures, in which low potential electrons in the conduct band of component ‘A’ cross the phase boundary and recombine with the holes in the valence band of component ‘B’ (Figure a). However, during long-range migration, the photogenerated carriers can readily undergo bulk recombination within the components, thus breaking the carrier migration based on the Z-scheme.…”