Silver-loaded InS-CdInS@X(X=Ag, AgPO, AgI) ternary heterostructure nanotubes treated by electron beam irradiation with enhanced photocatalytic activity.

Ternary heterostructure nanotubes of InS-CdInS@X(X = Ag, AgPO, AgI) were synthesized with enhanced photocatalytic activity for efficiently degrading pollutants. Electron beam irradiation was employed to artificially introduce interface defects to the heterostructure nanotubes. The experimental results for degrading carmine and Cr under visible light irradiation showed that the photocatalytic efficiency of InS-CdInS was improved to some extent by the introduction of silver compounds. DRS results confirmed that the band gaps of InS-CdInS were reduced to 1.62 eV and 1.58 eV by introducing AgPO and AgI, respectively. Interestingly, the band gap of InS-CdInS@AgI after electron beam irradiation was further reduced to 1.56 eV, resulting in that the degradation time of both Cr and carmine by InS-CdInS@AgI after high-energy electron beam irradiation was shortened to only 5 min. The XRD spectra of the photocatalysts after five cycles could maintain the original crystal form to a large extent. The OH stretching vibration peaks of InS-CdInS@AgI after electron beam irradiation at 3387 cm became wider and sharper, thus indicating that the number of free hydroxyl groups on the heterostructure surface significantly increased. PL results showed that electron beam irradiation could significantly reduce the PL emission peak and enhance the utilization of photogenerated charge carriers. EIS results further confirmed that InS-CdInS@AgI processed by electron beam irradiation had higher photogenerated electron-hole separation efficiency. Based on the experimental results, a feasible reaction pathway and photocatalytic mechanism for the degradation of carmine was investigated. ESR results showed that the main active groups in the whole photocatalytic system were •O and h.