To investigate the effect of Gd doping on photocatalytic activity of BiFeO3 (BFO), Gd-doped BFO nanoparticles containing different Gd doping contents (Bi(1−x)GdxFeO3, x = 0.00, 0.01, 0.03, 0.05) were synthesized using a facile sol-gel route. The obtained products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectra, and ultraviolet-visible diffuse reflectance spectroscopy, and their photocatalytic activities were evaluated by photocatalytic decomposition of Rhodamine B in aqueous solution under visible light irradiation. It was found that the Gd doping content could significantly affect the photocatalytic activity of as-prepared Gd-doped BFO, and the photocatalytic activity increased with increasing the Gd doping content up to the optimal value and then decreased with further enhancing Gd doping content. To elucidate the enhanced photocatalytic mechanism of Gd-doped BFO, the trapping experiments, photoluminescence, photocurrent and electrochemical impedance measurements were performed. On the basis of these experimental results, the enhanced photocatalytic activities of Gd-doped BFO could be ascribed to the increased optical absorption, the efficient separation and migration of photogenerated charge carriers as well as the decreased recombination probability of electron-hole pairs derived from the Gd doping effect. Meanwhile, the possible photocatalytic mechanism of Gd-doped BFO was critically discussed.

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A novel heterostructured CuO/BiFeO3 composite photocatalyst was successfully prepared through a simple combination of hydrothermal and impregnation process. CuO was uniformly deposited on the surface of BiFeO3 particles with a p–n heterojunction formed at the interface between CuO and BiFeO3. CuO/BiFeO3 heterostructured photocatalysts improved the UV/Vis spectral absorption ability, and exhibited enhanced photocatalytic activities for photodegradation of methylorange or a colorless compound (i.e., phenol) under visible light. In addition, after five recycles for the photodegradation of methylorange, CuO/BiFeO3 did not exhibit significant loss of photocatalytic activity, confirming its stability and long‐time reusability. The enhanced photocatalytic activity could be mainly ascribed to the p–n heterojunction structure between CuO and BiFeO3, which could significantly facilitate the separation and transfer of photogenerated electron–hole pairs. On the basis of the calculated energy bands, the photocatalytic mechanism was also proposed.

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Selective synthesis of valuable primary amines is an important target in modern industry. Amination of alcohols with ammonia is an economically efficient and environmentally friendly process for primary amine synthesis. This consecutive reaction yields a mixture of primary, secondary, and tertiary amines. High selectivity to primary amines is an important challenge of alcohol amination. Carbon deposition on the catalyst surface is conventionally considered an undesirable process, which leads to poor catalytic performance. In this paper, carbon deposition produced by catalyst pretreatment with alcohols under the optimized conditions has been employed for major enhancement of the selectivity of alcohol amination to primary amines (from 30 to 50 to 80–90%). This extremely positive effect of carbon deposition on the amination selectivity arises from steric hindrance in hydrogenation of bulky secondary imines as intermediate products over partially carbon-decorated cobalt nanoparticles.

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