The high interfacial charge transfer barrier has been a primary thermodynamic obstacle in enhancing the catalytic performance of heterojunction materials. Optimizing the interfacial environment is a promising strategy to attain superior catalytic efficiency. Hence, a Bi/Bi2MoO6/Bi24O31Br10 (Bi/BMO/BOB) composite photocatalyst was constructed by introducing a Bi–O–Mo bridge bond between the BMO and BOB interfaces and modifying metal active sites on the surface of the complex. Bi/BMO/BOB has a good capacity for CO2 photoreduction to CO. The CO yield of the Bi/BMO/BOB photocatalyst is 68.29 μmol g−1 h−1, which is obviously higher than those of the pristine BMO and BOB. As proved by density functional theory (DFT) calculations and experimental characterization, the Bi–O–Mo interface bridge bond adjusts the electronic structure of the contact interface and enhances the interface charge separation and transport rate. Moreover, the metal Bi nanoparticles synthesized through in situ reduction not only realize electron transfer and storage as electron collectors, but also strengthen the adsorption of CO2 molecules. The synergistic action of the two can allow the effective transfer of photogenerated electrons from BMO to BOB, which then accumulate on Bi. Such stepwise transfer of electrons increases the speed of photocatalytic reduction processes that involve multiple electrons, and effectively reduces the reaction energy barrier in the process of CO2 reduction. This mode of interatomic electron transfer bridges combined with the metal active sites not only solves the stability issues in bismuth-based semiconductors, but also aids in the development of more efficient photocatalytic systems for reduction of CO2.
Wangman Yin,Xinman Tu,Xinding Lv,Li Zhang,Tingting Li,Xiaojun Wang,Jianping Zou
The photocatalytic fuel cell (PFC) can treat the increasingly severe pollution from flotation wastewater in the mining industry by simultaneously converting the chemical energy of pollutants into electricity. The inherent thermodynamic and kinetic differences in degradation pathways are crucial for governing pollutant mineralization and electricity generation in the PFC system. However, achieving simultaneous contaminant elimination and maximum energy recovery through rational pathway modulation remains challenging. Herein, oxygen vacancy-enriched heterostructured BiPO 4 /Bi 2 MoO 6 photoanode by B/P co-doping, denoted as BPO/BP-BMO, is constructed via a one-step acid-mediated solvothermal method. The in-situ heterojunction and oxygen vacancies induced by heteroatom doping effectively modulate electronic/band structures, optimize interfacial charge transfer, and enhance electron-hole pair separation efficiency. The optimal BPO/BP-BMO photoanode exhibits enhanced production of singlet oxygen ( 1 O 2 ) under visible-light irradiation, which is critical for regulating the degradation pathways of sodium isopropyl xanthate (SIPX). Experimental and theoretical studies have shown that 1 O 2 preferentially targets the -O-CSS- bond in SIPX, leading to the rapid formation of isopropanol, a compound that mineralizes quickly, while minimizing the buildup of unreactive intermediates such as ROCS₂O − . The isopropanol-oriented degradation pathway endows the BPO/BP-BMO-PFC system with 92 % degradation efficiency within 90 min and a power density of 9.7 μW cm −2 , with the latter being 1.8 times that of the Bi 2 MoO 6 -PFC system. This study demonstrates an advanced photoanode, progressing from rational defect/heterojunction design to degradation pathways regulation, thereby establishing a more effective PFC system for sustainable wastewater-to-energy conversion processes.
Novel Bismuth molybdate@polydopamine-Au nanocomposites (Bi2MoO6@PDA-Au) were synthesized and used to construct a sensor for enhanced electrochemical determination of nitrite (NO2−). Bi2MoO6@PDA-Au was investigated with scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectroscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and the results showed a large number of Au nanoparticles were uniformly distributed on 3D Flowerlike Bi2MoO6 microspheres coated with PDA. Electrochemical techniques were employed to study electrochemical performance, and the results revealed that the sensor has an excellent response to NO2− with a comprehensive linear range of 0.3 μM to 4.4 mM, which is an order of magnitude wider than that obtained by the CQD-PEDOT/GCE and two orders of magnitude wider than that obtained by the Au-MoS2/GCE. In addition, the sensor also displayed good reproducibility, reusability, long-termstability, fast response time, and anti-interference performance. It is expected that Bi2MoO6@PDA-Au nanocomposites could be a promising material in the practical efficient detection of NO2−.
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