Understanding the role of Ce sites for boosting PEC-NIRR without externally applied potentials†
Abstract
Photoelectrochemical nitrate reduction reaction (PEC-NIRR) is a promising technology of nitrogen fixation, which has the advantages of mild conditions and small carbon footprint. However, due to the low selectivity and competitive hydrogen evolution reaction (HER), PEC-NIRR still faces a critical challenge to achieve the efficient production of NH3. For the first time, in this study, Ce-doped p-BiVO4 was fabricated and applied to PEC-NIRR. Ce3+ mainly replaced the Bi3+ sites in the p-BiVO4 matrix, and the reversible redox ability of Ce effectively promoted internal carrier migration and surface catalytic kinetics. Without the externally applied potentials (0 V vs. RHE), 1.5% Ce–BiVO4 showed desirable activity, and the NH3 yield of 1.5% Ce–BiVO4 reached 31.54 μg h−1 cm−2, which is 3.9 times that of p-BiVO4. The selectivity of NH3 (relative to NO2−) was enhanced to 24.5 times, compared with that of pristine p-BiVO4. In addition, 1H nuclear magnetic resonance (1H NMR) spectroscopy verified that the source of N was entirely NO3−. Therefore, this work identifies the critical role of Ce sites for tailoring the nature of p-BiVO4 for efficient PEC-NIRR.
- This article is part of the themed collection: FOCUS: Photocatalysis
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