This study aims to develop highly efficient ammonia (NH₃) adsorbents to address odor issues in pet care. Porous organic polymers (POPs) were modified through dual-agent co-impregnation method with citric acid and nickel chloride to enhance their NH₃ adsorption capacity. Performance was evaluated through static and dynamic adsorption tests, with systematic characterization of physicochemical properties. Results indicate that compared to pristine POPs, the modified POPs exhibit a 340% increase in NH₃ adsorption capacity at ambient temperature and pressure. The breakthrough time and saturation time are extended by 9 min and 33 min, respectively. Adsorption performance shows only slight decay over extended storage periods, remaining superior to pristine POPs. The modification caused micropore blockage, reducing the specific surface area and total pore volume while increasing the average pore diameter. The density of surface acidic functional groups, primarily carboxyl groups, significantly increases, and nickel chloride becomes more uniformly dispersed on the adsorbent surface, which is key to the enhanced adsorption performance. This study provides a new approach for designing and preparing high-performance NH₃ adsorbents based on POPs.