Frustrated Lewis pairs boosting photoelectrochemical nitrate reduction over ZnIn2S4/BiVO4 heterostructure

Photoelectrochemical nitrate reduction reaction (PEC-NIRR) is a green approach to ammonia (NH3) production. However, PEC system still suffers from the unsatisfactory chemisorption and NIRR kinetics. Here, we firstly designed a ZnIn2S4/BiVO4 heterostructure with zinc vacancies (VZn), and the steric hindrance further induces the formation of “frustrated Lewis pairs (FLPs)”, which simultaneously achieve the efficient chemisorption and kinetics of nitrate (NO3−). Furthermore, electron-density isosurface revealed the structure and energy distribution in FLPs. The accuracy of the NO3−→NH3 conversion was further valued by 15N isotope tracking. The selectivity of NH3 was 34.1 times that of nitrite (NO2−), and the NH3 yield rate reached as high as 29.95 μg h−1 cm−2. Therefore, this work identifies the critical role of FLPs for enhancing the selective chemisorption and catalytic kinetics, expanding the prospect of FLPs active site in the field of PEC-NIRR.