In situ fabrication of CdMoO4/g-C3N4 composites with improved charge separation and photocatalytic activity under visible light irradiation

To further improve the charge separation and photocatalytic activities of g-C3N4 and CdMoO4 under visible light irradiation,CdMoO4/g-C3N4 composites were rationally synthesized by a facile precipitation-calcination procedure.The crystal phases,morphologies,chemical compositions,textural structures,and optical properties of the as-prepared composites were characterized by the corresponding analytical techniques.The photocatalytic activities toward degradation of rhodamine B solution were evaluated under visible light irradiation.The results revealed that integrating CdMoO4 with g-C3N4 could remarkably improve the charge separation and photocatalytic activity,compared with those of pristine g-C3N4 and CdMoO4.This would be because the CdMoO4/g-C3N4 composites could facilitate the transfer and separation of the photoexcited electron-hole pairs,which was confirmed by electrochemical impedance spectroscopy,transient photocurrent responses,and photoluminescence measurements.Moreover,active species trapping experiments demonstrated that holes(h+)and superoxide radicals(?O2?)were the main active species during the photocatalytic reaction.A possible photocatalytic mechanism was proposed on the basis of the energy band structures determined by Mott-Schottky tests.This work would provide further insights into the rational fabrication of composites for organic contaminant removal.

Liquid exfoliating CdS and MoS_(2) to construct 2D/2D MoS_(2)/CdS heterojunctions with significantly boosted photocatalytic H2 evolution activity

Fabrication of 2D/2D heterojunction photocatalysts have attracted more attentions due to their inherent merits involving the large contact interface,short charge migration distance and plentiful active sites,which are beneficial for the enhancement of photocatalytic activity.Herein,a series of 2D/2D MoS_(2)/Cd S type-I heterojunctions were prepared by incorporation the exfoliating of bulk CdS and MoS_(2) with postsintering procedure.Multiple characteristic techniques were employed to corroborate the formation of heterojunctions.By optimizing the 2D MoS_(2) amounts in the heterojunction,the 7 wt.%2D/2D MoS_(2)/CdS heterojunction displayed the maximal photocatalytic H2 evolution rate of 18.43 mmol h^(-1) g^(-1) under visible light irradiation in the presence of lactic acid as the sacrificial reagent,which was 6 times higher than that of pristine 2D CdS.Based on the photoelectrochemical and photoluminescence spectra tests,it could be deduced that the charge separation and transfer of 2D/2D MoS_(2)/CdS heterojunction was tremendously improved,and the recombination of photoinduced electron-hole pairs was effectively impeded.Moreover,the 2D MoS_(2) was used as a cocatalyst to provide the abundant active sites and lower the overpotential for H_(2) generation reaction.The current work would offer an insight to fabricate the 2D/2D heterojunction photocatalysts for splitting H_(2)O into H_(2).