Retorting Photocorrosion and Enhanced Charge Carrier Separation at CdSe Nanocapsules by Chemically Synthesized TiO₂ Shell for Photocatalytic Hydrogen Fuel Generation

Abstract

Metal chalcogenide‐based semiconductor nanostructures are promising candidates for photocatalytic or photoelectrocatalytic hydrogen generation. In order to protect CdSe from photocorrosion, a layer of TiO2 wrapped (shell) onto CdSe (core) nanocapsule via the post‐synthesis process. The morphology studies confirm that a thin crystalline TiO2 shell (3–8 nm) wrapped in all the three directions onto CdSe core and thickness of the shell can be controlled through modulating the titania precursor concentration. The feasibility of pristine CdSe nanocapsules and CdSe@TiO2 in transforming visible light to hydrogen conversion was tested through photocatalysis reaction. The CdSe@TiO2 nanocapsules generated a four‐fold high rate of hydrogen gas (21 mmol.h−1.g−1cat) than pristine CdSe. In order to understand the role of shell@core, we have studied the photoelectrochemical and impedance analysis. The CdSe@TiO2 nanocapsules showed higher photoelectric current generation and lower charge transfer resistance at electrode/electrolyte interfaces compared to pristine CdSe. These studies endorse that chemically synthesized crystalline TiO2 shell played a multifunctional role in (a) surface passivation from photocorrosion, (b) promoting photocharge carrier separation via tunneling process between CdSe and TiO2 interface. As a result, CdSe@TiO2 nanocapsules showed a high conversion efficiency of 12.9 % under visible light irradiation (328 mW.cm−2) and a TOF of 0.05018 s−1.

Solar hydrogen generation from organic substance using earth abundant CuS–NiO heterojunction semiconductor photocatalyst

“…[34]. The similar type of functional nature of CuS/NiO heterostructures has been previously reported [35][36][37]. In general, the binding energy values obtained from XPS bands in this work are in good agreement with standard XPS binding energy values of Cu, S, Ni and O found in the previous reports [38].…”

Temperature-Driven Morphology Control on CdSe Nanofractals and Its Influence over the Augmented Rate of H2 Evolution: Charge Separation via the S-Scheme Mechanism with Incorporated Cu3P

“…Meanwhile, the core peak at 133.2 eV of P 2p spectrum (Figure 7f) could be assigned to the binding energy of P 2p 3/2 , which is in good agreement with the earlier reports. 56,57 From the existing results, it is clearly seen that before and after incorporation of Cu 3 P, the peak positions of Cd and Se in the deconvoluted spectrum were not altered. This clearly implies that there is no peak shift.…”

Hierarchical Co0.85Se‐CdSe/MoSe2/CdSe Sandwich‐Like Heterostructured Cages for Efficient Photocatalytic CO2 Reduction

“…The results showed that the formed sandwich‐like tandem heterostructure further inhibited their photocorrosion. [ 32 ] Owing to their intimate interfacial contact and matched band position, the photogenerated electrons of CdSe can transfer quickly to MoSe 2 nanosheets. On the other hand, the holes transfer to the other side to oxidize H 2 O to form O 2 , thus suppressing the backward reaction and photocorrosion.…”