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We have fabricated K0.5Na0.5NbO3 (KNN) thin films on Pt substrates by a chemical solution deposition method and investigated the effect of K and Na excess (0–30 mol%) on ferroelectric and piezoelectric properties of KNN thin film. It was found that with increasing K and Na excess in a precursor solution from 0 to 30 mol%, the leakage current and ferroelectric properties were strongly affected. KNN thin film synthesized by using 20 mol% K and Na excess precursor solution exhibited a low leakage current density and well saturated ferroelectric P–E hysteresis loops. Moreover, the optimized KNN thin film had good fatigue resistance and a piezoelectric constant of 40 pm V−1, which is comparable to that of polycrystalline PZT thin films.

A bulk heterojunction photocatalyst of interfacing CaFe(2)O(4) and MgFe(2)O(4) nanoparticles is highly active for oxidative degradation of isopropyl alcohol and hydrogen production from water under visible light, because the exciton easily reaches the interface and dissociates to minimize recombination.

The Pb substitution effect was investigated experimentally and theoretically on the crystal structure of BaSnO3 and on the photo-oxidation activity of H2O. The chemically doped Pb in BaSnO3 induced a concentration-dependent redshift of the experimental band gap (BG). The BaPb0.8Sn0.2O3 system produced 32μmol∕h of O2 under λ⩾420nm photons, but no O2 for BaSnO3. The DFT calculations of BaPbxSn1−xO3 (x=0,0.5,1) by using generalized approximation, implying the BG alteration and the photocatalytic activity of BaPbxSn1−xO3, are due to the induced Pb 6s orbital in the BG of BaSnO3. Thus Pb modified the insulating nature of BaSnO3 to semiconducting and semimetallic.

A uniform array of Aurivillius phase perovskite PbBi2Nb2O9 photocatalyst in a nanorod configuration is fabricated on a conducting glass as a photoelectrode for a photo‐electrochemical water oxidation. Dramatically improved photoactivity is demonstrated for the nanorod electrode compared to a PbBi2Nb2O9 particulate electrode. Directional electron transport in crystalline nanorods is faster than percolation through a random polycrystalline particle network.