N-isopropylacrylamide polymer brushes alter the micro-solvation environment during aqueous nitrite hydrogenation on Pd/Al2O3 catalyst

Nitrite contaminants in freshwater streams, resulting from run-off of fertilizers and livestock farming, are a major ecological challenge. Here, we have developed new family catalysts based on Pd/Al2O3 coated with N-isopropylacrylamide polymer (p-NIPAM) brushes that increase N-N bond formation over N-H formation, promoting nitrogen selectivity by 3-fold, reaching >99% for the containing 20 wt% carbon form p-NIPAM, without significant drops catalytic activity (TOF c.a. 6.8 ± 1.1 min?1). Strikingly, rigorous mass transport studies revealed presence p-NIPAM does not limit transfer molecules during hydrogenation nitrites aqueous phase. These observations were corroborated detailed reaction kinetics which similar activation barriers disappearance 30–34 kJ mol?1 obtained regardless content. The observed orders un-coated catalysts, indicating rate determining step, most likely NOX-H remained unaltered. apparent ammonia however, drastically increased 41 3 to 63 4 76 5 7 C counterparts, respectively. Contrary widely accepted operation mode thermo-responsive brushes, demonstrated these polymers modify chemical environment near active site as shown in-situ ATR data, tunning catalyst altering molecular transport. results will facilitate development more selective liquid phase reactions relevant drinking water purification.