The electrocatalytic nitrate reduction reaction (NO 3 − RR) has immense potential to alleviate the problem of groundwater pollution and may also become a key route for the environmentally benign production of ammonia (NH 3 ) products. Here, the unique effects of interfacial electric fields arising from asymmetric chemical potentials and local defects were integrated into the binary Bi 2 S 3 -Bi 2 O 3 sublattices for enhancing electrocatalytic nitrate reduction reactions. The obtained binary system showed a superior Faraday efficiency (FE) for ammonia production of 94 % and an NH 3 yield rate of 89.83 mg g cat -1 h −1 at −0.4 V vs. RHE. Systematic experimental and computational results confirmed that the concerted interplay between interfacial electric fields and local defects not only promoted the accumulation and adsorption of NO 3 – , but also contributed to the destabilization of *NO and the subsequent deoxygenation hydrogenation reaction. This work will stimulate future designs of heterostructured catalysts for efficient electrocatalytic nitrate reduction reactions.
Jun Feng,Tao Jiang,Yingchun Han,Otieno Kevin Okoth,Ling Cheng,Jingdong Zhang
A dual Z-scheme Bi 2 S 3 /Bi 2 O 3 /WO 3 ternary film was constructed via a controllable reduction of peroxotungstate by ethanol, calcination of Bi (NO 3 ) 3 and in situ anion exchange of Bi 2 O 3 with sulfide. The as-prepared composite film was characterized by scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The UV–visible diffuse reflectance spectroscopic and photoluminescence studies indicated that the introduction of Bi 2 S 3 in Bi 2 O 3 /WO 3 film effectively improved the absorption of the film in the visible region and suppressed the recombination of photogenerated carriers. The photoelectrocatalytic activity of the Bi 2 S 3 /Bi 2 O 3 /WO 3 film was evaluated by decoloration of Rhodamine B under visible light illumination. Compared with WO 3 and Bi 2 O 3 /WO 3 films, the Bi 2 S 3 /Bi 2 O 3 /WO 3 film exhibited much higher degradation efficiency. Moreover, the enhanced visible light photoelectrocatalytic activity of the Bi 2 S 3 /Bi 2 O 3 /WO 3 film was also demonstrated by efficient degradation of diclofenac. According to the reactive oxygen species detected by electron spin resonance, a dual Z-scheme system formed in the Bi 2 S 3 /Bi 2 O 3 /WO 3 film was proposed, which offered a new approach to the construction of semiconducting composite film with high photoelectrocatalytic performance for pollutant removal.
Photoelectrochemical devices have garnered extensive research attention in the field of smart and multifunctional photoelectronics, owing to their lightweight nature, eco-friendliness, and cost-effective manufacturing processes. In this work, Bi2S3/Bi2O3/TiO2heterojunction film was successfully fabricated and functioned as the photoelectrode of photoelectrochemical devices. The designed Bi2S3/Bi2O3/TiO2photoelectrochemical photodetector possesses a broad light detection spectrum ranging from 400 to 900 nm and impressive self-powered characteristics. At 0 V bias, the device exhibits an on/off current ratio of approximately 1.3 × 106. It achieves a commendable detectivity of 5.7 × 1013Jones as subjected to a 0.8 V bias potential, outperforming both bare TiO2and Bi2O3/TiO2photoelectrochemical devices. Moreover, the Bi2S3/Bi2O3/TiO2photoelectrode film shows great promise in pollutant decomposition, achieving nearly 97.7% degradation efficiency within 60 min. The appropriate band energy alignment and the presence of an internal electric field at the interface of the Bi2S3/Bi2O3/TiO2film serve as a potent driving force for the separation and transport of photogenerated carriers. These findings suggest that the Bi2S3/Bi2O3/TiO2heterojunction film could be a viable candidate as a photoelectrode material for the development of high-performance photoelectrochemical optoelectronic devices.
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