Recently large electrocaloric effects (ECE) (ΔT = 12 K and ΔS = 8 JK-1 kg-1 at 776 kVcm-1) in antiferroelectric sol-gel PbZr 0.95 Ti 0.05 O 3 thin film and (ΔT = 12.6 K and ΔS = 60 JK-1 kg-1 at 2090 kVcm-1) in ferroelectric polymer P(VDF-TrFE)55/45 thin film were observed near their ferroelectric Curie temperatures 495 K and 353 K, respectively. Here authors demonstrate a giant EC effect (ΔT = 45.3 K and ΔS = 46.9 JK-1 kg-1 at 598 kVcm-1) in relaxor ferroelectric Pb 0.8 Ba 0.2 ZrO 3 (PBZ) thin film fabricated on Pt(111)/TiO x /SiO 2 /Si substrate by a sol-gel method, in which nano-scaled antiferroelectric (AFE) and ferroelectric (FE) phases coexist, at room temperature (290 K) rather than at its Curie temperature (408 K). The giant ECE in such a system is attributed to the coexistence of AFE and FE phases and field-induced nano-scaled AFE to FE phase transition. The giant ECE of PBZ thin film makes it a promising material for the application in cooling systems near room temperature.

Nitrogen self-doped graphitic carbon nitride was successfully synthesized by the co-thermal condensation of the precursor with a nitrogen-rich additive.

Zinc oxide (ZnO) and zeolitic imidazolate framework-8 (ZIF–8) core–shell heterostructures were obtained by using the self-template strategy where ZnO nanorods not only act as the template, but also provide Zn2+ ions for the formation of ZIF–8 shell. The ZIF–8 shell was uniformly deposited to form ZnO@ZIF–8 nanorods with core–shell heterostructures at 70 °C for 24 h as the optimum reaction time by the hydrothermal synthesis. Transmission electron microscopy (TEM) images revealed that the ZnO@ZIF–8 heterostructures are composed of ZnO as core and ZIF–8 as shell. Nitrogen (N2) sorption isotherms demonstrated that the as-prepared ZnO@ZIF–8 nanorods are a typical microporous material. Additionally, the ZnO@ZIF–8 nanorods sensor exhibited distinct gas response for reducing gases with different molecule sizes. The selectivity of the ZnO@ZIF–8 nanorods sensor was obviously improved for the detection of formaldehyde owing to the limitation effect of the aperture of ZIF–8 shell. This study demonstrated that semiconductor@MOF core–shell heterostructures may be a novel way to enhance the selectivity of the gas sensing materials.