A main object of the present disclosure is to provide a cathode active material used for a fluoride ion battery, the cathode active material comprising: a first active material having a composition represented by Pb.sub.2xCu.sub.1+xF.sub.6, wherein 0x<2; and a second active material containing a Bi element and a F element.

A main object of the present disclosure is to provide a cathode active material used for a fluoride ion battery, the cathode active material comprising: a first active material having a composition represented by Pb.sub.2xCu.sub.1+xF.sub.6, wherein 0x<2; and a second active material containing a Bi element and a F element.

A photocatalyst made of cuprous bromide, wherein the cuprous bromide expresses a photocatalytic property of decomposing a substance brought into contact with the cuprous bromide by irradiation with light.

A photocatalyst made of cuprous bromide, wherein the cuprous bromide expresses a photocatalytic property of decomposing a substance brought into contact with the cuprous bromide by irradiation with light.

Disclosed are a method for preparing a hydrophobic copper nanoclusters-containing colloidal solution and use of the hydrophobic copper nanoclusters-containing colloidal solution in detecting Fe.sup.3+. The hydrophobic copper nanoclusters-containing colloidal solution is prepared by dissolving Cu.sub.4I.sub.4 in dimethyl sulfoxide to obtain a solution of Cu.sub.4I.sub.4 in DMSO, and then performing self-assembly of the solution of Cu.sub.4I.sub.4 in DMSO with a EuW.sub.10 solution.

Disclosed are a method for preparing a hydrophobic copper nanoclusters-containing colloidal solution and use of the hydrophobic copper nanoclusters-containing colloidal solution in detecting Fe.sup.3+. The hydrophobic copper nanoclusters-containing colloidal solution is prepared by dissolving Cu.sub.4I.sub.4 in dimethyl sulfoxide to obtain a solution of Cu.sub.4I.sub.4 in DMSO, and then performing self-assembly of the solution of Cu.sub.4I.sub.4 in DMSO with a EuW.sub.10 solution.

A gas sensor device has a crystalline film of copper(I) bromide, wherein a crystal surface of the copper(I) bromide is formed of a stepped terrace having a flat face and a steep slope.

A gas sensor device has a crystalline film of copper(I) bromide, wherein a crystal surface of the copper(I) bromide is formed of a stepped terrace having a flat face and a steep slope.

Compositions suitable for reversibly storing heat in thermal energy systems (TES) include a salt hydrate represented by the formula: MX.sub.q.Math.nH.sub.2O. M is a cation selected from Groups 1 to 14 of the IUPAC Periodic Table, X is a halide of Group 17, q ranges from 1 to 4, and n ranges from 1 to 12. The cation (M) may have an electronegativity of about 1.8 and a molar mass about 28 g/mol. The anion (X) may have an electronegativity of about 2.9 to about 3.2. A distance between a cation (M) and coordinating water molecules (H.sub.2O) is about 2.1 . Thermal energy systems (TES) incorporating such compositions are also provided that are configured to reversibly store heat in the thermal energy system (TES) via an endothermic dehydration reaction and to release heat in in the thermal energy system (TES) via an exothermic hydration reaction.

Compositions suitable for reversibly storing heat in thermal energy systems (TES) include a salt hydrate represented by the formula: MX.sub.q.Math.nH.sub.2O. M is a cation selected from Groups 1 to 14 of the IUPAC Periodic Table, X is a halide of Group 17, q ranges from 1 to 4, and n ranges from 1 to 12. The cation (M) may have an electronegativity of about 1.8 and a molar mass about 28 g/mol. The anion (X) may have an electronegativity of about 2.9 to about 3.2. A distance between a cation (M) and coordinating water molecules (H.sub.2O) is about 2.1 . Thermal energy systems (TES) incorporating such compositions are also provided that are configured to reversibly store heat in the thermal energy system (TES) via an endothermic dehydration reaction and to release heat in in the thermal energy system (TES) via an exothermic hydration reaction.