•Copper glycinate monohydrate microrods were obtained by a simple solution method.•Porous CuO microrods were achieved via calcining the precursors.•The porous CuO microrods exhibit superior photocatalysis property.Porous copper oxide microrods have been synthesized via calcining copper glycinate monohydrate microrod precursor which was prepared in mild conditions without any template or additive. Several techniques, such as X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and Brunauer–Emmett–Teller (BET) N2 adsorption–desorption analyses, were used to characterize the structure and morphology of the products. Scanning electron microscopy (SEM) analyses show that the precursor consists of a large quantity of uniform rod-like micro/nanostructures with typical lengths in the range of 25–40 µm and diameters in the range of 0.1–0.35 µm. The microrod-like precursors transformed into porous microrod products after calcination at 450 °C in flow air for 2 h. The BET surface area of the porous CuO microrods was calculated to be 8.5 m² g−1. In addition, the obtained porous CuO microrods were used as catalysts to photodegrade rhodamine B (RhB), methyl orange, methylene blue, eosin B, and p-nitrophenol. Compared with commercial CuO powders, the as-prepared porous CuO microrods exhibit superior properties on photocatalytic decomposition of RhB due to their porous hierarchical structures.

•Zinc glycinate monohydrate microwires were obtained by a chemical solution method.•Porous ZnO microbelts were achieved after calcinations.•The porous ZnO microbelts exhibit superior gas-sensing property.Porous ZnO microbelts were achieved using a facile chemical solution method combined with subsequent calcination. The micro-nanostructures were characterized through X-ray diffraction, field emission scanning electron microscopy, thermogravimetric-differential thermal analysis, and Brunauer–Emmett–Teller N2 adsorption-desorption analyses, among others. The BET surface area of the porous ZnO microbelts was calculated at 23.0 m² g−1. Furthermore, the gas sensing properties of the as-prepared porous ZnO microbelts were investigated using volatile organic compounds. Compared with ZnO microflowers, the porous ZnO microbelts exhibited higher response with certain organic vapors, such as formaldehyde, acetone, and ethanol. The responses to 100 ppm formaldehyde, acetone, and ethanol were 45.7, 40.6, and 38.4, respectively, at a working temperature of 300 °C. The results showed that the porous ZnO microbelts are highly promising candidates for gas sensing applications.

Hollow porous Co-doped SnO2 microcubes were achieved by a template-free chemical solution route combined with subsequent alkali-washing, calcination and acid-washing process. Spontaneous phase segregation yields such a special hollow porous structure. Several techniques, such as X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric-differential thermal analysis, and Brunauer–Emmett–Teller N2 adsorption–desorption analyses, were used to characterize the structure and morphology of the products. During the process, alkali-washing in the first step is critical to the formation of the hollow structure. The process of inducing porosity starts with a crystalline single-phase hydroxide precursor CoSn(OH)6 formed by co-precipitation of the metal ions from aqueous solution. Thermal decomposition of the precursors leads to an intimate mixture of Co3O4 and porous tetragonal SnO2. The hollow porous Co-doped SnO2 microcubes are obtained after the Co3O4 phase has been removed by acid-washing. A decomposition–aggregation–dissolution process is proposed to demonstrate the formation of such a special structure. Furthermore, the gas sensing properties of the as-prepared hollow, porous, Co-doped SnO2 microcubes for some volatile organic vapors were tested, which exhibited a much better sensing performance than that of the porous Co-doped SnO2 microcubes, indicating that the special hollow porous Co-doped SnO2 structures are highly promising for applications as gas sensors.

Nanoflake-based flower-like CuO nanostructures have been synthesized through thermal decomposition of [Cu(NH3)4]2+ solution without any surfactants and catalysts at low temperature. The products are characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM). The possible formation process based on the aggregation-recrystallization mechanism is proposed. Finally, the obtained flowerlike CuO hierarchical nanostructures have been used as the photocatalyst in the experiments. It is found that the asprepared flower-like CuO hierarchical nanostructures exhibit superior photocatalytic property on photocatalytic decomposition of Rhodamine B due to their hierarchical structures.