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[Display omitted] • We develop a multifunctional p-n heterostructure material for SERS substrate. • Low concentrations of pollutants can be rapidly detected within 1 min. • The substrate exhibited excellent practicality in SERS detection. • CMS x has great potential to be cost-efficient wastewater purification materials. Monitoring toxic organic pollutants from water to protect the ecology of water resources is an important and challenging task. For this purpose, snowflake-like n-MoS 2 /p-Cu 2 S heterostructures with sensitivity and stability were synthesized by a simple method. The enhancement factor (EF) of 0.02MoS 2 /Cu 2 S substrate can reach 1.27 × 109 and limit of detection (LOD) is 10−12 M for methylene blue (MB) in lake water. Moreover, the 0.02MoS 2 /Cu 2 S showed excellent photocatalytic activity for degradation of organic pollutants (MB, CV, MG, R6G) which were removed with efficiencies of at least 70–99% within 24 min. This significant EF and photocatalytic performance are mainly attributed to the more "hot spots" offered by the distinctive morphology of Cu 2 S (confirmed by finite-difference time-domain (FDTD) simulation) and the increased charge-separation efficacy of p-n heterojunction owing to the 0.02MoS 2 /Cu 2 S. This study opens up new frontiers for the high-sensitivity detection and complete degradation of organic pollutants. The application of 0.02MoS 2 /Cu 2 S heterostructures to pollution problems provides a cost-effective solution for wastewater treatment. [ABSTRACT FROM AUTHOR]

Semiconducting stoichiometric copper sulphide (Cu2S) thin films were deposited using modified chemical deposition method. The preparative conditions such as concentration, pH of cationic and anionic precursors, adsorption, reaction and rinsing time durations, complextant, etc. were optimized to get stoichiometric Cu2S thin films. The structural, surface morphological, compositional, optical and electrical characterization were carried out with the help of X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Rutherford back scattering (RBS), optical absorbance/transmittance, electrical resistivity and thermoemf studies. The films were found to be nanocrystalline. Absorbance of the film was high (104 cm−1) with optical band gap of 2.35 eV. The electrical resistivity was of the order of 10−2 Ω cm with p-type electrical conductivity. [Copyright &y& Elsevier]

[Display omitted] • A high-performance Cu 2 S/Cu pre-catalytic electrode was presented. • The loaded Cu 2 S particles in situ transferred into CuO nanowires in OER process. • The Cu 2 S/Cu pre-catalytic electrode shows 373 mV of overpotential for 50 mA cm−2. • Great stability with 60 h oxygen evolution operation was demonstrated. Synthesizing low-cost and efficient materials to catalyze oxygen evolution reaction (OER) is urgently needed but remains challenging so far. In this study, Cu 2 S nanoparticles were prepared on Cu foam, forming a high-efficiency Cu 2 S/Cu foam robust pre-electrocatalysts. The Cu 2 S/Cu foam, as a new precatalyst for OER, presents an excellent efficiency with 373 mV of overpotential for 50 mA cm−2, which is superior to RuO 2 (400 mV). The Cu 2 S/Cu foam pre-electrocatalyst also demonstrates an impressive durability with a current retention of 86% after catalyzing OER for 60 h with a current density 60 mA cm−2. Moreover, the structure, morphology and phase transformation of the pre-electrocatalyst during the OER operation were revealed. It was found that the Cu 2 S nanoparticles will evolve into sulfate ions embedded CuO nanowires that catalyze oxygen evolution reaction. It is believed that the evolution of Cu 2 S nanoparticles to sulfate ions embedded CuO involve the oxidation reaction under the high overpotential and the disproportionate reaction of Cu(I) species. The result suggests that hybridized cuprous sulfide/copper materials are attractive noble-metal-free pre-catalysts for water splitting. Our study may offer a new way to develop metal sulfide catalysts for high-performance water oxidation reaction. [ABSTRACT FROM AUTHOR]

• Controlled etching of selected metal oxide and sulfide underlayers during ALD of Cu 2 S was observed. • The etch exhibited self-limiting characteristics dependent on the Cu precursor and H 2 S times. • As proof of concept, Cu 2 S nanowires were fabricated using ALD of Cu 2 S and the observed etching phenomenon. Herein, we report the simultaneous etching of selected metal oxide and sulfide underlayers during the atomic layer deposition (ALD) of Cu 2 S. The unexpected etch was observed to be prompted by the infiltration of highly mobile Cu+ ions from a top ALD Cu 2 S layer into underlying films, followed by fragmentation of the underlayers and subsequent outward diffusion of both cations and anions from the underlayers to the Cu 2 S surface. A strong correlation was observed between the susceptibility to etching, etch rates and the bond dissociation energies of the underlayers. ZnS, ZnO, SnS, and SnO thin films were etched at different rates, while SnO 2 exhibited high resistance to etching. Interestingly, the etch process exhibited self-limiting characteristics dependent on the Cu precursor and H 2 S gas dose times, thus indicating simultaneous Cu 2 S ALD and controlled sublayer etching reactions. Based on the findings, we proposed a possible mechanism by which the etching proceeds. We further explored, the synthesis of 3-dimensional Cu 2 S/ZnO and Cu 2 S nanowires using ALD Cu 2 S and the observed ZnO etching phenomenon. [ABSTRACT FROM AUTHOR]