Piezoelectric Catalysis Development for Nitrate Reduction Reaction (NO3RR)

Nitrate (NO3-) is widely regarded as one of the most persistent and pervasive contaminants in natural water systems, primarily originating from agricultural runoff, excessive fertilizer use, and industrial effluents. Its accumulation significantly disturbs the global nitrogen (N2) cycle, leading to various environmental and health challenges. Elevated nitrate levels accelerate eutrophication, stimulate harmful algal blooms, and deplete dissolved oxygen in aquatic environments, ultimately degrading water quality and threatening aquatic biodiversity. Furthermore, long-term consumption of nitrate-contaminated water has been epidemiologically associated with methemoglobinemia and certain cancers, highlighting its serious implications for public health. Therefore, nitrate contamination has emerged as a pressing environmental concern that demands sustainable remediation approaches and efficient treatment technologies. Ammonia (NH3), an essential industrial and agricultural feedstock, has recently drawn increasing attention as a hydrogen storage medium and promising clean energy carrier. Among the sustainable pathways for ammonia synthesis, electrocatalytic and photocatalytic reduction reactions have been explored for converting nitrogen-containing compounds-such as nitrogen (N2), nitrite (NO2-) and nitrate (NO3-) - into ammonia. Notably, the nitrate reduction reaction (NO3RR) offers a particularly attractive route, as nitrate is a common pollutant with relatively low bond dissociation energy compared to molecular nitrogen, enabling more energy-efficient conversion processes. Piezocatalysis is an emerging catalytic technology that exploits the intrinsic piezoelectric properties of certain materials to enable the conversion from the mechanical energy into the chemical energy. When a piezoelectric material experiences mechanical deformation, it induces an internal potential difference - known as a piezopotential - which effectively modulates the band structure and facilitates charge carriers’ separation. Recently, the applications of piezocatalysis have increased beyond conventional areas such as organic dye degradation and hydrogen evolution to encompass emerging fields like greenhouse gas mitigation. Ongoing research increasingly focuses on its potential in environmental purification, renewable energy production and storage, and biotechnological processes, highlighting the versatility and growing significance of this innovative catalytic approach. This research focuses on the piezoelectric catalysis development for nitrate reduction reaction (NO3RR). The first two phases of the study focus on exploring optimal transition metal dopants to enhance both the nitrate reduction efficiency and ammonia production rate, as well as fine-tuning reaction parameters to achieve the highest performance. The third phase emphasizes improving catalytic performance through material coupling, where constructing heterojunction structures is considered a promising strategy for boosting activity and overall production rate. Building upon these findings, subsequent experiments are designed to further validate and refine this approach. Overall, this work highlights the rational design and modification of piezocatalysts for achieving efficient nitrate to ammonia conversion, contributing to the advancement of piezoelectric catalysis for nitrate reduction reaction (NO3RR).