Shufang Wang,Shanshan Chen,Guoying Yan,Fuqiang Liu,Shouyu Dai,Jianglong Wang,Wei Yu,Guangsheng Fu
c-axis oriented nanocrystalline Bi 2 Sr 2 Co 2 O y thin films with the average grain size of 25 nm have been achieved by chemical solution deposition combined with a rapid annealing process in oxygen. The resistivity and Seebeck coefficient of the nanostructured films are about 7.0 mΩ·cm and 171 μV/K at 873 K, resulting in a power factor 2–3 times larger than that of the best reported value in the coarse-grained Bi 2 Sr 2 Co 2 O y polycrystalline bulks. Since the thermal conductivity can be greatly reduced due to the increased phonon scattering at the grain boundaries of nanocrystalline films as well as at film surface and at film/substrate interface, great improvements in the ZT are expected in the nanocrystalline Bi 2 Sr 2 Co 2 O y thin films .
Two-dimensional materials have garnered significant attention in recent years due to their remarkable electron-hole transfer capability. However, the advancement of convenient and rapid synthesis techniques remains crucial for further research in this field. In this study, lamellar anatase/rutile-TiO 2 phase heterojunctions with a favorable phase interface was synthesized through a fast annealing route using glucose as the template and titanium tetrachloride. The sample synthesized at 600 °C with a holding time of 20 min exhibited the most significant levels of H 2 evolution activity (53.22 mmol g −1 h −1 ) with a low loading of 0.05 wt% Pt co-catalyst, which is significantly higher than the commercial P25 sample. The characterization reveals that the anatase/rutile-TiO 2 phase heterojunction in the two-dimensional sheet exhibits excellent phase interface contact and possesses a large specific surface area with an appropriate pore size. These characteristics are advantageous for facilitating the separation and migration of carriers, thereby enhancing the efficiency of the H 2 production reaction through hydrolysis. This study presents a novel approach towards the advancement of highly effective two-dimensional photocatalysts.
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