Modification of large area Cu2O/CuO photocathode with CuS non-noble catalyst for improved photocurrent and stability

In this work, a three-layered heterostructure Cu2O/CuO/CuS was obtained through a low-cost and large-area fabrication route comprising electrodeposition, thermal oxidation, and reactive annealing in a sulfur atmosphere. Morphological, microstructural, and compositional analysis (AFM, SEM, XRD, EDS, XPS) were carried out to highlight the surface modification of cuprous oxide film after oxidation and subsequent sulfurization. Impedance, voltammetric, and amperometric photoelectrochemical tests were performed on Cu2O, Cu2O/CuO, and Cu2O/CuO/CuS photocathodes in a sodium sulfate solution (pH 5), under 100 mW cm−2 AM 1.5 G illumination. A progressive improvement in terms of photocurrent and stability was observed after oxidation and sulfurization treatments, reaching a maximum of − 1.38 mA cm−2 at 0 V versus RHE for the CuS-modified Cu2O/CuO electrode, corresponding to a ~ 30% improvement. The feasibility of the proposed method was demonstrated through the fabrication of a large area photoelectrode of 10 cm2, showing no significant differences in characteristics if compared to a small area photoelectrode of 1 cm2.

Liquid phase assisted grain growth in Cu2ZnSnS4 nanoparticle thin films by alkali element incorporation

We present a route where organic ligand-free, KCl-functionalized Cu2ZnSnS4 nanoparticles grow into large, dense grains during annealing in nitrogen/sulfur atmosphere.

Synthesis of Europium Sulfides by CS2 Sulfurization and Heat Treatment

ABSTRACTThe formation of europium sulfides (Eu3S4 and EuS) via CS2 gas sulfurization of Eu2O3 powder was investigated. Single-phase Eu3S4 was obtained via CS2 gas sulfurization of Eu2O3 at 773 K for periods longer than 0.5 hr and EuS was generated by sulfurization at 1073 K for 8 hr. The higher sulfurization temperature and shorter sulfurization time accelerated the formation of high purity EuS. Synthetic pure Eu3S4 was treated under vacuum, rich-sulfur atmosphere and inert atmosphere, respectively. EuS was obtained when heat treatment was performed at 873 K under vacuum, at 973 K under CS2/Ar atmosphere, and at 1073 K under Ar atmosphere. Heat treatment of Eu3S4 generated a small amount of Eu2O2S due to impurity oxygen. Formation of Eu2O2S could be inhibited by heat treatment under CS2/Ar atmosphere.