Search

van der Waals (vdW) heterostructures have received tremendous attention in low dimensional semiconductors due to interfacial surface reconstruction and electronic coupling effects. Here, we report mixed-dimensional 2D/1D In2S3@Bi2S3 heterostructures synthesized via a two-step solvothermal in situ growth. Theoretical calculations demonstrate that In2S3 nanosheets and Bi2S3 nanorods are integrated together through the vdW interaction. Through theoretical calculations and experiments, the results confirm that the surface potential of Bi2S3 is higher than that of In2S3, implying that the free electrons will flow from Bi2S3 to In2S3 when the two semiconductors come into contact, leading to electron and hole accumulation at the In2S3 and Bi2S3 surface. This redistribution of charges will induce an outward vector of a built-in electric field at the In2S3@Bi2S3 interface (from Bi2S3 to In2S3), thereby improving hole transfer to In2S3 and electron transfer to Bi2S3. The advanced heterostructure aids in shortening the photogenerated electrons' transport time (14 μs), promoting the electron–hole separation, and presents a 13.3-fold enhancement in photocurrent density when compared to In2S3. [ABSTRACT FROM AUTHOR]

Shape-controlled synthesis of non-noble metal nanocrystals (NCs) is vital to their catalysis applications due to their different exposed surfaces and atomic coordination environments. Here, we report a facile synthesis of Ni nanocubes and cuboctahedra with controlled shapes and high yields via a wet-chemistry strategy. The key to success relies on the use of cetyltrimethyl ammonium bromide (CTAB), formaldehyde (HCHO) and a specific reaction temperature, which could effectively cap the desired surface and tune their growth rate. Specifically, nanocubes switched to cuboctahedra and octahedra with an increased reaction temperature due to gradual CO desorption from the surfaces of NCs. Meanwhile, it should be worth noting that CTAB and the generated CO molecules through HCHO decomposition would co-adsorb on the {100} facets of Ni NCs. As a proof-of-application, the obtained Ni NCs exhibited high activity in the oxygen evolution reaction (OER) with over-potentials of 383 mV and 402 mV for nanocubes and cuboctahedra at a current density of 10 mA cm−2, respectively, demonstrating that the {100} facets are more favorable toward OER. These results suggested that their performance is strongly shape dependent and is derived from different surface energies and active sites. [ABSTRACT FROM AUTHOR]