Construction of CdS/MoS₂ heterojunction from core–shell MoS₂@Cd-MOF for efficient photocatalytic hydrogen evolution

Abstract

A CdS/MoS2 heterojunction with uniform loading of CdS nanoparticles, porous structure, and controllable heterojunction surface was synthesized from a core–shell MoS2@Cd-MOF precursor and exhibited a high photocatalytic H2 evolution rate.

An Efficient and Stable MoS2/Zn0.5Cd0.5S Nanocatalyst for Photocatalytic Hydrogen Evolution

“…[32,41] The characteristic peak for S2 sa t2 26.1 eV corresponds to at ypical feature of MoS 2 . [47] Twop eaks at 161.5 and 162.7 eV divided from S2 p peak can be attributed to S2 p 3/2 and S2 p 1/2 ,r espectively, which correspond to the S 2À oxidation state (FigureS7e in the Supporting Information). [32,33,47] The photocatalytic activities of Zn x Cd 1Àx Sf or HER under visible-lighti rradiationw ere studied for optimizationo ft he Zn/Cd ratios with sodium sulfide and sodium sulfite as sacrificial agents withouta ny noble-metalc ocatalysts ( Figure S8 in the Supporting Information).…”

“…[47] Twop eaks at 161.5 and 162.7 eV divided from S2 p peak can be attributed to S2 p 3/2 and S2 p 1/2 ,r espectively, which correspond to the S 2À oxidation state (FigureS7e in the Supporting Information). [32,33,47] The photocatalytic activities of Zn x Cd 1Àx Sf or HER under visible-lighti rradiationw ere studied for optimizationo ft he Zn/Cd ratios with sodium sulfide and sodium sulfite as sacrificial agents withouta ny noble-metalc ocatalysts ( Figure S8 in the Supporting Information). The photocatalytic HER rate of CdS derived from apure Cd-ZIF-8 is only 0.60 mmol h À1 g À1 .W ith in-creasingZ nc ontent, the HER rate of Zn x Cd 1Àx Sg radually increasesa nd reaches am aximum 8.16 mmol h À1 g À1 for Zn 0.5 Cd 0.5 S, which is 13.6 times greater than that of CdS.…”

“…[52] With the above equations, we determinedt he CB and VB positions of Zn x Cd 1Àx S( Ta ble S3 in the Supporting Information).A ni ncreased Zn content in Zn x Cd 1Àx Ss olid solution results in widened bandgaps and raised CB edges in comparison to pure CdS, which has low photocatalytic activity due to fast recombination of the photogenerated carriers. Zn 0.5 Cd 0.5 S showedo ptimized photocatalytic performanceb ecause it balances the light absorptionc apacity and CB edgep osition, which is beneficialt oe ffectively separate the photogenerated electrons and holes.A st he bandgapo fM oS 2 has been determined to be 1.8 eV, [47] the CB edge and VB edge of MoS 2 are À0.08 and 1.72 eV at the zero point, respectively,w hich indicates that the CB edge potential is more positivet han that of Zn 0.5 Cd 0.5 S. Under visible light, both Zn 0.5 Cd 0.5 Sa nd MoS 2 could be exciteda nd generate electrons and holes. MoS 2 in the heterojunction acts as the active site for HER, because photogenerated electrons couldb et ransferred from the CB of Zn 0.5 Cd 0.5 S to MoS 2 with favorable band alignment.…”

“…Figure S7 d in the Supporting Information shows Mo 3d 5/2 and Mo 3d 3/2 peaks at 228.6 and 232.1 eV, respectively, which are typical for Mo 4+ . The characteristic peak for S 2s at 226.1 eV corresponds to a typical feature of MoS 2 . Two peaks at 161.5 and 162.7 eV divided from S 2p peak can be attributed to S 2p 3/2 and S 2p 1/2 , respectively, which correspond to the S 2− oxidation state (Figure S7 e in the Supporting Information) …”

Novel Architecture Titanium Carbide (Ti3C2Tx) MXene Cocatalysts toward Photocatalytic Hydrogen Production: A Mini-Review

“…Transition metal surface such as CdS [69][70][71], CdSe [72], MoS 2 [73][74][75], and WS 2 [76][77][78] has been demonstrated as potential catalysts for electrocatalytic and photocatalytic HER. Therefore, the coupling of these materials with Ti 3 C 2 T x might produce the composite with unprecedented performance in photocatalytic HER.…”