Indium vacancy modulated BiVO4/ZnIn2S4 for photoelectrochemical production of ammonia

Abstract

Background

Photoelectrochemical (PEC) reduction of nitrate to produce ammonia (NIRR) is a green strategy for converting waste NO₃⁻ into high-value chemicals. However, a lack of active sites and low selectivity still plague the single catalyst used to establish the PEC-NIRR system.

Methods

Here, we construct a BiVO₄/V_In-ZnIn₂S₄ (BVO/V_In-ZIS) heterostructure with indium vacancies. The introduction of indium vacancy significantly enhances the conversion of NO₃⁻ to NH₃ by augmenting active sites and fostering carrier separation via the creation of a built-in electric field.

Significant findings

NH₃ yield of BVO/V_In-ZIS heterostructure with moderate indium vacancy (BVO/V_In-ZIS-m) has been promoted to 15.26 μg h⁻¹ cm⁻² (BVO/V_In-ZIS-m), and NH₃ selectivity reaches 21.3 times that of NO₂⁻. The results of cyclic experiments further demonstrate that NH₃ yield of BVO/V_In-ZIS-m has remained 98.4% after five cycles, due to its excellent durability. Therefore, this work demonstrates that indium vacancy could significantly modulate the PEC performance of BiVO₄ to achieve an efficient NH₃ production.