Chi Cao,Jinshuo Li,Linfeng Zhang,Yang Hu,Lin Zhang,Wensheng Yang
Herein, a new type of two-dimensional (2D)/2D Ti 3 C 2 /TiO 2 heterojunction was developed for efficient photocatalytic nitrogen reduction reaction (NRR), in which TiO 2 nanosheets (TiO 2 Ns) were designed as the main catalyst, while Ti 3 C 2 MXene served as the co-catalyst. Experimental and theoretical results revealed that Ti 3 C 2 MXene introduced electron-rich unsaturated Ti sites, serving as highly active sites for both the adsorption and activation of N 2 on the Ti 3 C 2 /TiO 2 heterojunction. Furthermore, the 2D/2D Ti 3 C 2 /TiO 2 heterostructure greatly promoted the directional separation and transfer of charge carriers, facilitated by the internal electric field. This structural feature enabled the spatial separation of the N 2 reduction and H 2 O oxidation half-reactions on the distinct surfaces of Ti 3 C 2 (001) and TiO 2 (001), consequently reducing the reaction energy barrier for each respective process. The synergistic effects arising from the interface and surface interactions within the heterojunction conspicuously improved the photocatalytic NRR activity. As a result, the optimized Ti 3 C 2 /TiO 2 heterojunction exhibited a high NH 3 production rate of 24.4 μmol g -1 h -1 in the absence of sacrificial agents, representing a remarkable 12.8-fold increase compared to individual TiO 2 Ns. This work provides new insights into rational design of high-performance heterogeneous photocatalysts and offers a deeper understanding of the mechanism underlying surface active sites in the photocatalytic NRR process.
Herein, a novel, recognition-molecule-free electrode based on Ti3C2/TiO2composites was synthesized using Ti3C2as the Ti source and TiO2in situ formed by oxidation on the Ti3C2surface for the selective detection of dopamine (DA). The TiO2in situ formed by oxidation on the Ti3C2surface not only increased the catalytically active surface for DA binding but also accelerated the carrier transfer due to the coupling between TiO2and Ti3C2, resulting in a better photoelectric response than pure TiO2. Through a series of experimental conditions optimization, the photocurrent signals obtained by the MT100 electrode were proportional to the DA concentration from 0.125 to 400 µM, with a detection limit estimated at 0.045 µM. We also monitored DA in human blood serum samples using the MT100 electrode. The results showed good recovery, demonstrating the promising use of the sensor for the analysis of DA in real samples.Keywords:photoelectrochemical;MXene;dopamine sensor
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