The severe recombination of photoinduced carriers is one of the major problems encountered in C 3 N 4 -based photocatalyst for hydrogen generation. Herein, PtPd/C 3 N 4 composites by in situ growth of cubic PtPd bimetallic co-catalyst on the surface of C 3 N 4 were constructed for photocatalytic hydrogen generation under visible light irradiation. The phase structure, microstructure, and optical property were characterized by X-ray diffraction, transmission electron microscopy, and UV-Vis diffuse reflectance spectroscopy. Photocatalytic hydrogen generation results showed that the growth of a moderate amount of cubic PtPd bimetallic co-catalyst on C 3 N 4 is excellent beneficial for enhancing hydrogen generation activity. By optimizing the loading content of cubic PtPd bimetallic co-catalyst, the PtPd/C 3 N 4 composite provided a maximum hydrogen generation rate of 54.31 μmol h −1 . The enhancement of the photocatalytic activity can be attributed to the efficient separation and transfer of photoinduced carriers. On one hand, PtPd bimetal can extract electrons from C 3 N 4 , which promotes the separation efficiency of the carriers. On the other hand, the face-to-face interface formed between PtPd cubes and C 3 N 4 nanosheets has a large contact area, resulting in lots of unique high-speed carrier transfer channels in PtPd/C 3 N 4 composite, which promotes the transfer efficiency of the carriers. The work highlights the construction of less expensive and suitable shape of co-catalyst for enhanced photocatalytic activity.
The shape-dependent performance of metal co-catalysts in photocatalysis has been one of the research focal points in recent years. In this study, PtPd/C 3 N 4 hybrid structures were constructed to reveal the effect of the shape of the PtPd bimetallic co-catalyst on the performance of photocatalytic hydrogen generation. PtPd nanocubes (NCs) and nanotetrahedrons (NTs) were sequentially deposited in situ on the surface of C 3 N 4 nanosheets, establishing a strong contact interface to ensure the smooth transfer of photoinduced electrons. Ultraviolet–visible (UV–Vis) diffuse reflectance spectroscopy and photoelectrochemical experiments revealed that the PtPd NCs/C 3 N 4 photocatalyst had comparable light absorption ability and equivalent carrier separation and transfer efficiency in comparison with the PtPd NTs/C 3 N 4 photocatalyst, which excluded the influence of these factors on shape-dependent performance. The photocatalytic hydrogen generation results indicate that the hydrogen generation rate of the PtPd NCs/C 3 N 4 photocatalyst is 1.33 times higher than that of the PtPd NTs/C 3 N 4 photocatalyst, demonstrating that the cubic PtPd bimetallic co-catalyst is more conducive to hydrogen generation compared to the tetrahedral PtPd bimetallic co-catalyst. Graphical abstract
Ziyue Sun,Hongli Zhao,Kaicha Chen,Fangfang Zhou,Minbo Lan
In this work, the carbon fiber microelectrode (CFME) coated by ERGO-CNT network was used as a substrate to support dendrite PtPd nanoclusters. An enzyme-free O 2 − electrochemical sensor (PtPd@ERGO-CNT-CFME) was prepared based on this strategy. Due to the brilliant loading and dispersing abilities of the substrate and the excellent electrochemical activity of the dendrite PtPd alloy, PtPd@ERGO-CNT-CFME demonstrated outstanding detection ability towards O 2 − . The as-constructed sensor showed a wide-linear range of 16–744 μM and 744–3064 μM with high sensitivity of 6967.3 μA mM −1 cm −2 and 4124.3 μA mM −1 cm −2 , and the detection limit was 5.07 μM. Furthermore, PtPd@ERGO-CNT-CFME was successfully applied to monitor O 2 − released from living cells. This phenomenon indicated the application potential for O 2 − detection in biological samples.
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