Driving nitrogen conversion through piezoelectric and ferroelectric enhanced biohybrid systems.

Environmental nitrogen pollution resulting from various sources (e.g., industrial/municipal wastewater and agricultural runoff) poses a tough global challenge. Traditional approaches for transforming nitrogenous contaminants to inert N2 are often restricted by large operational costs, high energy dependence, and severe reaction bottlenecks. Recently, the discovery of direct mechanobiological activation has inspired a new frontier emerged, highlighting the potential to promote nitrogen conversion via an unprecedented abiotic-biotic synergy enabled by ferroelectric and piezoelectric materials. While previous reviews have focused on either bioelectrochemical nitrogen transformation or piezocatalytic nitrogen conversion, there is no comprehensive discussion that integrates these two domains and elucidates their interfacial coupling mechanisms. This review is aimed to fill this gap by critically examining this synergistic paradigm. We dissect how these materials function dually: they act as abiotic catalysts that form localized electric fields and reactive species, directly activating nitrogen molecules, and simultaneously as biotic stimulators that electronically interface with microbes, enhancing their metabolic denitrification pathways. How this synergy breaks conventional limitations is elaborated. The abiotic pathway can generate favorable microenvironments or intermediates used by the biotic pathway, while microbial activity in turn prevents catalyst fouling. However, practical application requires addressing the critical challenge of energy mismatch with ambient environments. Thus, key emerging strategies are assessed, including photo-mechanical synergy using sunlight as the primary power source while weak mechanical forces restrict charge recombination, and flexoelectric effects that harvest energy from low-frequency non-uniform strains. Harnessing this abiotic-biotic synergy through next-generation concepts can offer a transformative method for sustainable nitrogen remediation.