This work proposes a NOx recycling approach through nitrite hydrogenation into ammonia (NH3/NH4OH), and the screened out Pd0/Pd2+-loaded heterogeneous catalyst achieves excellent ammonia yield. Initially, the DFT calculation of nitrite hydrogenation was conducted to study the determining step for N2/ammonia generation and guide the catalyst design. Consequently, the designed Pd2+/0/ Covalent Triazine Framework (CTF) presented 100% nitrite conversion with 100% ammonia selectivity. The XPS and H2-TPR results demonstrated the Pd2+/Pd0 ratios and Pd2+ reducibility greatly affected the nitrite conversion and ammonia selectivity. DRIFTs examined the reaction intermediates and the impact of Pd distribution behind ammonia generation. Under ambient conditions, a model test from NOx adsorption to ammonia release has been completed, and it exhibited an overall conversion of 70% NOx into ammonia in a single cycle with TOF of 3.9 h−1, which proposes a direction of NOx recycling and utilization with less energy consumption and free of CO2 emissions. 

Hydrogenation of NO into ammonia under ambient conditions: from mechanistic investigation to multiphase catalysis

Synthesis of 3,4-dihydro-1,3,5-triazin-2(1H)-one derivatives by recycling 2H-1,3,5-oxadiazine-2,4(3H)-diimines: their spectral characteristics and molecular structure

Covalent triazine frameworks (CTFs) with structure designability and multifunctionalities have aroused increasing attention in conventional thermocatalysis and modern photocatalysis/electrocatalysis. However, many obstacles still exist on the road to simultaneously achieving...

Qin Sun

Papers

Metallic active-site engineering: a bridge of covalent triazine framework and high-performance catalysts